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1.
J Clin Oncol ; 18(4): 860-7, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10673529

RESUMEN

PURPOSE: A recent multicenter study of preoperative chemoradiation and pancreaticoduodenectomy for localized pancreatic adenocarcinoma suggested that biliary stent-related complications are frequent and severe and may prevent the delivery of all components of multimodality therapy in many patients. The present study was designed to evaluate the rates of hepatic toxicity and biliary stent-related complications and to evaluate the impact of this morbidity on the delivery of preoperative chemoradiation for pancreatic cancer at a tertiary care cancer center. PATIENTS AND METHODS: Preoperative chemoradiation was used in 154 patients with resectable pancreatic adenocarcinoma (142 patients, 92%) or other periampullary tumors (12 patients, 8%). Patients were treated with preoperative fluorouracil (115 patients), paclitaxel (37 patients), or gemcitabine (two patients) plus concurrent rapid-fractionation (30 Gy; 123 patients) or standard-fractionation (50.4 Gy; 31 patients) radiation therapy. The incidences of hepatic toxicity and biliary stent-related complications were evaluated during chemoradiation and the immediate 3- to 4-week postchemoradiation preoperative period. RESULTS: Nonoperative biliary decompression was performed in 101 (66%) of 154 patients (endobiliary stent placement in 77 patients and percutaneous transhepatic catheter placement in 24 patients). Stent-related complications (occlusion or migration) occurred in 15 patients. Inpatient hospitalization for antibiotics and stent exchange was necessary in seven of 15 patients (median hospital stay, 3 days). No patient experienced uncontrolled biliary sepsis, hepatic abscess, or stent-related death. CONCLUSION: Preoperative chemoradiation for pancreatic cancer is associated with low rates of hepatic toxicity and biliary stent-related complications. The need for biliary decompression is not a clinically significant concern in the delivery of preoperative therapy to patients with localized pancreatic cancer.


Asunto(s)
Adenocarcinoma/cirugía , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Conductos Biliares/patología , Terapia Neoadyuvante , Neoplasias Pancreáticas/cirugía , Pancreaticoduodenectomía , Stents/efectos adversos , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Ampolla Hepatopancreática , Antimetabolitos Antineoplásicos/administración & dosificación , Antineoplásicos Fitogénicos/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Neoplasias del Conducto Colédoco/tratamiento farmacológico , Neoplasias del Conducto Colédoco/radioterapia , Neoplasias del Conducto Colédoco/cirugía , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Femenino , Fluorouracilo/administración & dosificación , Estudios de Seguimiento , Hospitalización , Humanos , Incidencia , Hígado/efectos de los fármacos , Hígado/efectos de la radiación , Masculino , Persona de Mediana Edad , Paclitaxel/administración & dosificación , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/radioterapia , Dosificación Radioterapéutica , Estudios Retrospectivos , Gemcitabina
2.
J Clin Oncol ; 15(3): 928-37, 1997 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9060530

RESUMEN

PURPOSE: The effects of preoperative versus postoperative fluorouracil (5-FU)-based chemotherapy and irradiation on treatment toxicity, duration of treatment, tumor recurrence, and survival were compared in patients who underwent potentially curative therapy for adenocarcinoma of the pancreatic head during a 5-year period. METHODS: From July 1990 to July 1995, 142 patients with localized adenocarcinoma of the pancreatic head deemed resectable on the basis of radiographic images were treated with curative intent using a multimodality approach involving either preoperative or postoperative chemoradiation. Patients with biopsy confirmation of adenocarcinoma and a low-density mass in the pancreatic head identified by computed tomography (CT) received preoperative chemoradiation. Patients without a mass on CT or in whom the preoperative biopsy was negative underwent pancreaticoduodenectomy with planned postoperative chemoradiation. Protocol-based preoperative chemoradiation consisted of external-beam irradiation at a dose of 50.4 Gy (standard fractionation; 1.8 Gy/d, 5 d/wk) or 30 Gy (rapid fractionation; 3 Gy/d, 5 d/wk) combined with continuous infusion 5-FU (300 mg/m2/d, 5 d/wk). Postoperative chemoradiation combined 50.4 Gy of external-beam irradiation (standard fractionation) with continuous-infusion 5-FU. RESULTS: No patient who received preoperative chemoradiation experienced a delay in surgery because of chemoradiation toxicity, but six of 25 eligible patients (24%) did not receive postoperative chemoradiation because of delayed recovery after pancreaticoduodenectomy. No significant differences in toxicities from chemoradiation were observed between groups. Patients treated with rapid-fractionation preoperative chemoradiation had a significantly (P < .01) shorter duration of treatment (median, 62.5 days) compared with patients who received postoperative chemoradiation (median, 98.5 days) or standard-fractionation preoperative chemoradiation (median, 91.0 days). At a median followup of 19 months, no significant differences in survival were observed between treatment groups. No patient who received preoperative chemoradiation and pancreaticoduodenectomy experienced a local recurrence; peritoneal (regional) recurrence occurred in 10% of these patients. Local or regional recurrence occurred in 21% of patients who received pancreaticoduodenectomy and postoperative chemoradiation. CONCLUSION: Delivery of preoperative and postoperative chemoradiation in patients who underwent potentially curative pancreaticoduodenectomy for adenocarcinoma of the pancreatic head resulted in similar treatment toxicity, patterns of tumor recurrence, and survival. Rapid-fractionation preoperative chemoradiation ensured the delivery of all components of therapy to all eligible patients with a significantly shorter duration of treatment than with standard-fractionation chemoradiation given either before or after pancreaticoduodenectomy. Prolonged recovery after pancreaticoduodenectomy prevents the delivery of postoperative adjuvant chemoradiation in up to one fourth of eligible patients.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/radioterapia , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/radioterapia , Pancreaticoduodenectomía , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Protocolos Clínicos , Terapia Combinada , Estudios de Seguimiento , Humanos , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/cirugía , Estudios Prospectivos , Análisis de Supervivencia
3.
J Clin Oncol ; 16(12): 3843-50, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9850029

RESUMEN

PURPOSE: To evaluate the toxicities, radiographic and pathologic responses, and event-free outcomes with combined modality treatment that involves preoperative rapid-fractionation chemoradiation, pancreaticoduodenectomy, and electron-beam intraoperative radiation therapy (EB-IORT) for patients with resectable pancreatic adenocarcinoma. PATIENTS AND METHODS: Patients with radiographically resectable localized adenocarcinoma of the pancreatic head were entered onto a preoperative protocol that consisted of a 2-week course of fluorouracil (5-FU) 300 mg/m2 daily 5 days per week and concomitant rapid-fractionation radiation 30 Gy, 3 Gy daily 5 days per week. Radiographic restaging was performed 4 weeks after chemoradiation, and patients with localized disease underwent pancreaticoduodenectomy with EB-IORT 10 to 15 Gy. RESULTS: Thirty-five patients were entered onto the study and completed chemoradiation, 34 (97%) as outpatients. Three patients (9%) experienced grade 3 nausea and vomiting; no other grade 3 or 4 toxicities were observed. Of the 27 patients taken to surgery, 20 patients (74%) underwent pancreaticoduodenectomy with EB-IORT. All patients had a less than grade III pathologic response to preoperative chemoradiation. At a median follow-up of 37 months, the 3-year survival rate in patients who underwent combined modality therapy was 23%. CONCLUSION: Combined modality treatment with preoperative rapid-fractionation chemoradiation, pancreaticoduodenectomy, and EB-IORT is associated with minimal toxicity and excellent locoregional control. This represents one approach to maximize the proportion of patients who receive all components of combined modality therapy and avoids the toxicity of pancreaticoduodenectomy in patients found to have metastatic disease at the time of restaging.


Asunto(s)
Adenocarcinoma/terapia , Antimetabolitos Antineoplásicos/uso terapéutico , Fluorouracilo/uso terapéutico , Neoplasias Pancreáticas/terapia , Pancreaticoduodenectomía , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/radioterapia , Adenocarcinoma/cirugía , Adulto , Antimetabolitos Antineoplásicos/administración & dosificación , Antimetabolitos Antineoplásicos/efectos adversos , Terapia Combinada , Fraccionamiento de la Dosis de Radiación , Electrones/uso terapéutico , Femenino , Fluorouracilo/administración & dosificación , Fluorouracilo/efectos adversos , Humanos , Masculino , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/radioterapia , Neoplasias Pancreáticas/cirugía , Radioterapia Adyuvante/efectos adversos , Radioterapia Adyuvante/métodos , Análisis de Supervivencia , Resultado del Tratamiento
4.
J Clin Oncol ; 18(6): 1378-91, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10715310

RESUMEN

PURPOSE: To determine clinical practice guidelines for the use of bisphosphonates in the prevention and treatment of bone metastases in breast cancer and their role relative to other therapies for this condition. METHODS: An expert multidisciplinary panel reviewed pertinent information from the published literature and meeting abstracts through May 1999. Additional data collected as part of randomized trials and submitted to the United States Food and Drug Administration were also reviewed, and investigators were contacted for more recent information. Values for levels of evidence and grade of recommendation were assigned by expert reviewers and approved by the panel. Expert consensus was used if there were insufficient published data. The panel addressed which patients to treat and when in their course of disease, specific drug delivery issues, duration of therapy, management of bony metastases with other therapies, and the public policy implications. The guideline underwent external review by selected physicians, members of the American Society of Clinical Oncology (ASCO) Health Services Research Committee, and the ASCO Board of Directors. RESULTS: Bisphosphonates have not had an impact on the most reliable cancer end point: overall survival. The benefits have been reductions in skeletal complications, ie, pathologic fractures, surgery for fracture or impending fracture, radiation, spinal cord compression, and hypercalcemia. Intravenous (IV) pamidronate 90 mg delivered over 1 to 2 hours every 3 to 4 weeks is recommended in patients with metastatic breast cancer who have imaging evidence of lytic destruction of bone and who are concurrently receiving systemic therapy with hormonal therapy or chemotherapy. For women with only an abnormal bone scan but without bony destruction by imaging studies or localized pain, there is insufficient evidence to suggest starting bisphosphonates. Starting bisphosphonates in patients without evidence of bony metastasis, even in the presence of other extraskeletal metastases, is not recommended. Studies of bisphosphonates in the adjuvant setting have yielded inconsistent results. Starting bisphosphonates in patients at any stage of their nonosseous disease, outside of clinical trials, despite a high risk for future bone metastasis, is currently not recommended. Oral bisphosphonates are one of several options which can be used for preservation of bone density in premenopausal patients with treatment-induced menopause. The panel suggests that, once initiated, IV bisphosphonates be continued until evidence of substantial decline in a patient's general performance status. The panel stresses that clinical judgment must guide what is a substantial decline. There is no evidence addressing the consequences of stopping bisphosphonates after one or more adverse skeletal events. Symptoms in the spine, pelvis, or femur require careful evaluation for spinal cord compression and pathologic fracture before bisphosphonate use and if symptoms recur, persist, or worsen during therapy. The panel recommends that current standards of care for cancer pain, analgesics and local radiation therapy, not be displaced by bisphosphonates. IV pamidronate is recommended in women with pain caused by osteolytic metastasis to relieve pain when used concurrently with systemic chemotherapy and/or hormonal therapy, since it was associated with a modest pain control benefit in controlled trials. CONCLUSION: Bisphosphonates provide a meaningful supportive but not life-prolonging benefit to many patients with bone metastases from cancer. Further research is warranted to identify clinical predictors of when to start and stop therapy, to integrate their use with other treatments for bone metastases, to identify their role in the adjuvant setting in preventing bone metastases, and to better determine their cost-benefit consequences.


Asunto(s)
Neoplasias Óseas/prevención & control , Neoplasias Óseas/secundario , Neoplasias de la Mama/patología , Difosfonatos/uso terapéutico , Femenino , Humanos
5.
Clin Cancer Res ; 7(8): 2246-53, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11489798

RESUMEN

Gemcitabine has modest activity in the treatment of advanced pancreatic cancer and is a potent radiosensitizer. We conducted a Phase I trial to determine the maximum tolerated dose of weekly gemcitabine delivered concurrently with radiation therapy for the treatment of locally advanced adenocarcinoma of the pancreatic head and to assess the treatment-related toxic effects associated with such a regimen. Eighteen patients with pathologically proven, locally advanced adenocarcinoma of the pancreatic head were enrolled in this study. Patients received seven weekly doses of gemcitabine with 3000 cGy of external beam radiation therapy delivered during the first 2 weeks of therapy. Six patients received gemcitabine at 350 mg/m(2)/week, nine at 400 mg/m(2)/week, and three at 500 mg/m(2)/week. Grade 3-4 hematological toxicity was observed in over half the patients treated. Nonhematological toxicities were significant and included fatigue, anorexia, nausea, vomiting, and dehydration. Forty-four % of the patients required admission to the hospital for management of nausea/vomiting and dehydration. The risk of hospitalization appeared to be dose-related; all of the three patients treated at 500 mg/m(2)/week required hospital admission during treatment. Seventeen patients were evaluated for response, and eight patients (47%) had evidence of a local anticancer effect. Four of these eight patients (24%) had a partial response to therapy. The median survival for the entire group was 6 months. The 1-year survival rate for patients with an objective response to therapy was 66%. The clinical responses observed in this group of patients suggest gemcitabine is a clinically relevant radiosensitizer in patients with pancreatic adenocarcinoma. However, the toxic effects are significant, suggesting that until dose and scheduling issues are explored further, concomitant administration of gemcitabine and radiation therapy should still be considered investigational.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Antimetabolitos Antineoplásicos/uso terapéutico , Desoxicitidina/uso terapéutico , Neoplasias Pancreáticas/tratamiento farmacológico , Adenocarcinoma/radioterapia , Adulto , Anciano , Anorexia/etiología , Antimetabolitos Antineoplásicos/efectos adversos , Terapia Combinada/efectos adversos , Desoxicitidina/efectos adversos , Desoxicitidina/análogos & derivados , Relación Dosis-Respuesta a Droga , Fatiga/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Náusea/etiología , Neoplasias Pancreáticas/radioterapia , Resultado del Tratamiento , Vómitos/etiología , Gemcitabina
6.
Front Biosci ; 3: E193-203, 1998 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-9792895

RESUMEN

Adjuvant 5-fluorouracil and concurrent radiation may improve survival following complete surgical resection in patients with pancreatic adenocarcinoma. However, the morbidity and prolonged recovery associated with pancreaticoduodenectomy frequently prevents the timely delivery of postoperative chemoradiation. Therefore, the University of Texas M.D. Anderson Cancer Center (MDACC) has investigated the use of neoadjuvant chemoradiation in potentially resectable pancreatic cancer. We have incorporated a standardized approach to pretreatment staging, operative technique and pathologic evaluation. Our initial experience suggests that preoperative chemoradiation is well tolerated and may reduce loco-regional recurrence. Patients treated with rapid-fractionation preoperative chemoradiation had a significantly shorter duration of treatment compared with patients who received postoperative chemoradiation or standard-fractionation preoperative chemoradiation. New and more potent radiation-sensitizing agents such as gemcitabine may further enhance local control. Novel therapies directed at specific molecular events involved in pancreatic tumorigenesis may be incorporated into preoperative and postoperative regimens to attempt to reduce systemic relapse.


Asunto(s)
Adenocarcinoma/terapia , Terapia Combinada , Neoplasias Pancreáticas/terapia , Adenocarcinoma/mortalidad , Adenocarcinoma/patología , Quimioterapia Adyuvante , Humanos , Terapia Neoadyuvante , Estadificación de Neoplasias , Neoplasias Pancreáticas/mortalidad , Neoplasias Pancreáticas/patología , Pancreaticoduodenectomía/métodos , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Radioterapia Adyuvante , Tasa de Supervivencia , Tomografía Computarizada por Rayos X
7.
Semin Oncol ; 28(3 Suppl 10): 25-33, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11510031

RESUMEN

We compared and evaluated available laboratory and clinical data on the use of concurrent gemcitabine (Gemzar; Eli Lilly and Company, Indianapolis, IN) and radiation in pancreatic cancer to provide guidance for subsequent prospective research initiatives. Preclinical data suggest that the timing of administration of gemcitabine with respect to radiotherapy is important, but this issue has not yet been confirmed by clinical data. Phase I clinical data indicate that the amount of acute toxicity from the combination of gemcitabine and radiotherapy is strongly related to the dose and schedule of administration of gemcitabine, as well as to the radiation field size. There also appears to be an inverse linear relationship between the maximum tolerated gemcitabine dose and radiation dose. Also important, but less clear, is the infusion rate of gemcitabine as it relates to the systemic efficacy of the drug. The combination of additional agents with gemcitabine and radiation appears to be feasible. Finally, the addition of radioprotectors may enable chemotherapy dose escalation, but safe escalation of the radiotherapy dose with newer techniques has not been established. Semin Oncol 28 (suppl 10):25-33.


Asunto(s)
Antimetabolitos Antineoplásicos/uso terapéutico , Desoxicitidina/uso terapéutico , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/radioterapia , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Antimetabolitos Antineoplásicos/administración & dosificación , Ensayos Clínicos como Asunto , Terapia Combinada , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Relación Dosis-Respuesta a Droga , Relación Dosis-Respuesta en la Radiación , Esquema de Medicación , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Fármacos Sensibilizantes a Radiaciones/administración & dosificación , Dosificación Radioterapéutica , Gemcitabina
8.
Int J Radiat Oncol Biol Phys ; 23(3): 647-52, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1612966

RESUMEN

This study evaluated the response to a defined mouth care and analgesic treatment protocol for oropharyngeal mucositis in patients undergoing radiation therapy for head and neck carcinoma. Nineteen patients completed a 15 question pain survey before each radiation treatment. Patients were given instructions on the use of mouthwashes and a three-step analgesic protocol: acetaminophen, acetaminophen with codeine suspension, and oral morphine (20 mg/mL) for mild, moderate, and severe pain, respectively. Patients were seen daily by a radiation therapy nurse who reviewed the survey and prompt changes in the prescribed analgesic regimen were then made by a physician. Marked differences in control of pain related to radiation mucositis were observed when compared to patients from our prior study who used the same daily survey but had only sporadic nursing intervention and no analgesic protocol. Patients having daily nursing intervention reported fewer days of moderate/severe pain, had less pain throughout the day, and noted less disturbance in sleep, eating, and energy level. Weight loss of greater than 5 kg was noted in only three patients. Analgesics were used on 77% of treatment days and relieved all or most of the pain in 94% of these days. Daily review of a symptom survey by a radiation therapy nurse, combined with a well-defined strategy for mouth care, and analgesics results in improved pain management of radiation induced oropharyngeal mucositis because of prompt attention to patient needs. Future trials should incorporate defined strategies for oral care and analgesic use to control for possible bias in assessing efficacy.


Asunto(s)
Neoplasias de Cabeza y Cuello/radioterapia , Manejo del Dolor , Dimensión del Dolor/métodos , Adulto , Anciano , Femenino , Neoplasias de Cabeza y Cuello/enfermería , Humanos , Masculino , Persona de Mediana Edad , Radioterapia/efectos adversos , Radioterapia/enfermería
9.
Int J Radiat Oncol Biol Phys ; 28(3): 773-5, 1994 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-7726877

RESUMEN

Radiotherapy in Vietnam represents a stark contrast to the level of care available in the United States. The issue of efficient administration of cancer care with available resources is common to both nations. The challenge for each country is to develop treatment strategies and political policies for effective and accessible care within budgetary constraints. Results of therapy, defined as the restoration of function, must be the measure of efficacy and efficiency. This demands a balance between control of tumor-related symptoms and treatment-related morbidity. The most inefficient use of resources is an ineffective treatment that results in complications, as we observed in Vietnam. As health care policies continue to develop in the United States, we must not fail to focus upon therapeutic outcome as the single most important parameter for measuring success relative to the personal and public investment in medicine.


Asunto(s)
Instituciones Oncológicas , Países en Desarrollo , Neoplasias/radioterapia , Humanos , Vietnam
10.
Int J Radiat Oncol Biol Phys ; 21(5): 1343-51, 1991 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-1938534

RESUMEN

Development of secondary malignancies following treatment of Hodgkin's disease with radiation (central axis midline dose of 3600-4500 cGy) is a recognized risk, and the incidence in breast cancer has been reported to increase by a factor of 4.3 (95% confidence level 2.0 to 8.4) for patients treated with mantle irradiation. Increased incidence of breast cancer has also been shown in atomic bomb survivors, women who underwent multiple fluoroscopic examinations, and women treated for postpartum mastitis. The dose response, however, for radiation dose above 1000 cGy is virtually unknown. Quantitative analysis of carcinogenesis after radiation is exacerbated by the large dose gradient across the breast (300-4200 cGy for midline doses of 4000 cGy), large individual variation in breast size and treatment field position. We have developed differential dose volume histograms calculated using a 3-dimensional (Eg TAR) algorithm as a potential tool for retrospective and prospective epidemiological evaluation. The breast volume forms a bimodal distribution with respect to dose and with further analysis other quantities, such as mean dose and integral dose, can be calculated from the histograms. Using the mean dose, the linear model for carcinogenesis predicts an increased incidence of secondary breast cancer by a factor of 11.6 and 9.6 for the left and right breast, respectively. The dose calculations has been corrected for inhomonogenities 3-dimensionally and test of the accuracy has been included.


Asunto(s)
Neoplasias de la Mama/etiología , Neoplasias Inducidas por Radiación/etiología , Neoplasias Primarias Secundarias/etiología , Dosificación Radioterapéutica , Radioterapia/efectos adversos , Computadores , Femenino , Enfermedad de Hodgkin/radioterapia , Humanos , Riesgo
11.
Int J Radiat Oncol Biol Phys ; 34(4): 923-30, 1996 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-8598372

RESUMEN

PURPOSE: The objective of this work was to demonstrate the feasibility of using an artificial neural network to predict the clinical evaluation of radiotherapy treatment plans. METHODS AND MATERIALS: Approximately 150 treatment plans were developed for 16 patients who received external-beam radiotherapy for soft-tissue sarcomas of the lower extremity. Plans were assigned a figure of merit by a radiation oncologist using a five-point rating scale. Plan scoring was performed by a single physician to ensure consistency in rating. Dose-volume information extracted from a training set of 511 treatment plans on 14 patients was correlated to the physician-generated figure of merit using an artificial neural network. The neural network was tested with a test set of 19 treatment plans on two patients whose plans were not used in the training of the neural net. RESULTS: Physician scoring of treatment plans was consistent to within one point on the rating scale 88% of the time. The neural net reproduced the physician scores in the training set to within one point approximately 90% of the time. It reproduced the physician scores in the test set to within one point approximately 83% of the time. CONCLUSIONS: An artificial neural network can be trained to generate a score for a treatment plan that can be correlated to a clinically-based figure of merit. The accuracy of the neural net in scoring plans compares well with the reproducibility of the clinical scoring. The system of radiotherapy treatment plan evaluation using an artificial neural network demonstrates promise as a method for generating a clinically relevant figure of merit.


Asunto(s)
Pierna , Redes Neurales de la Computación , Planificación de la Radioterapia Asistida por Computador , Sarcoma/radioterapia , Estudios de Factibilidad , Humanos , Dosificación Radioterapéutica
12.
Int J Radiat Oncol Biol Phys ; 20(4): 815-21, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2004960

RESUMEN

Dual energy photon irradiation (6 MV and 20 MV) was compared to conventional treatment planning with 6 MV photons in a lateralized intracranial malignancy. Dose volume analysis was performed of both the tumor plus a 2 cm margin (target volume, TV) and normal tissues (NT). Parallel opposed treatment using weightings of 1:1, 1.5:1, and 2:1 were compared for 6 MV photons alone or in combination with 20 MV photons. Uniform treatment of the TV was accomplished within the 60 Gy isodose. Significant differences were observed, however, in NT volumes receiving greater than or equal to 60 Gy and 45-59 Gy. Dual photon energy reduced treatment of NT volumes to greater than or equal to 60 Gy by 13% (177 cm3 vs 204 cm3 in 2:1 weighting) to 70% (147 cm3 vs 498 cm3 in 1:1 weighting) for comparable plans. Dose optimization was also performed for both 6 MV alone or in combination with 20 MV photons. Usual approaches to achieve dose lateralization with conventional isocentric techniques were applied including parallel opposed 6 MV photons ipsilaterally weighted 3.4:1 (POP), and a 110 degrees arc rotational field used to limit treatment to the eye (ARC). Dual energy photon optimized plans included a three beam parallel opposed plan (TOP) and a mixed photon ipsilateral (IPSI) approach. The technique using parallel opposed 20 MV photons and ipsilateral 6 MV photons (TOP) used beam weightings of 1.1 (contralateral 20 MVX): 1.6 (ipsilateral 6 MVX): 1 (ipsilateral 20 MVX) to achieve dose optimization. The ipsilateral approach with 6 MVX and 20 MVX (IPSI) used beam weightings of 1:1.4, respectively. All optimized plans demonstrated a 41% (120 cm3; POP) to 53% (95 cm3; TOP) improvement over parallel opposed 6 MV photons weighted 2:1 (204 cm3) in NT volume receiving greater than or equal to 60 Gy. Comparison of optimized treatment showed the IPSI plan to be superior, treating 12% of NT volume to greater than or equal to 60 Gy and 38% to 45-59 Gy; the 6 MV POP plan resulted in NT volumes of 15% and 51%, respectively, for those dose levels. Dual photon energy irradiation of lateralized intracranial malignancies allows reduction of dose to normal tissue volumes while achieving excellent coverage of the target volume. Treatment planning should be performed in all lateralized intracranial lesions to achieve dose optimization exploiting depth dose characteristics.


Asunto(s)
Neoplasias Encefálicas/radioterapia , Radioterapia/métodos , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Radiación , Dosificación Radioterapéutica , Tomografía Computarizada por Rayos X
13.
Int J Radiat Oncol Biol Phys ; 13(10): 1589-94, 1987 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3114184

RESUMEN

The image quality of portal films for megavoltage photon beams, when using the double-exposure technique, is poor compared to diagnostic quality, X ray images. A technique is described to record on a single film a megavoltage portal image superimposed upon a diagnostic X ray image, which provides the radiotherapist with "diagnostic quality" portal images. The technique uses a commercially available X ray tube mounted on the head of a 60Co unit. The alignment procedure, which uses a leveling device to ensure that the X ray focal spot and 60Co source are at the same location for each exposure, is confirmed by registering on film the image of an alignment marker. An evaluation of film-screen combination showed therapy verification film in a rare earth intensifying screen cassette to be best suited for this technique. The relationship between off-axis dose and the penumbral region of the portal image has been evaluated and should be useful in the interpretation of portal verification film relative to the treatment volume.


Asunto(s)
Radioterapia de Alta Energía/métodos , Radioisótopos de Cobalto/uso terapéutico , Humanos , Control de Calidad , Radioterapia de Alta Energía/instrumentación , Rayos X
14.
Int J Radiat Oncol Biol Phys ; 47(1): 203-8, 2000 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-10758325

RESUMEN

PURPOSE: Radiation Therapy Oncology Group (RTOG) physicians were surveyed to determine their approach to and attitudes toward cancer pain management. METHODS AND MATERIALS: Physicians completed a questionnaire assessing their estimates of the magnitude of pain as a specific problem for cancer patients, their perceptions of the adequacy of pain management, and their report of how they manage pain in their own practice setting. RESULTS: Eighty-three percent believed the majority of cancer patients with pain were undermedicated. Forty percent reported that pain relief in their own practice setting was poor or fair. Assessing a case scenario, 23% would wait until the patient's prognosis was 6 months or less before starting maximal analgesia. Adjuvants and prophylactic side effect management were underutilized in the treatment plan. Barriers to pain management included poor pain assessment (77%), patient reluctance to report pain (60%), patient reluctance to take analgesics (72%), and staff reluctance to prescribe opioids (41%). CONCLUSIONS: Physicians' perceptions of barriers to cancer pain management remain quite stable over time, and physicians continue to report inadequate pain treatment education. Future educational efforts should target radiation oncologists as an important resource for the treatment of cancer pain.


Asunto(s)
Encuestas de Atención de la Salud , Neoplasias/complicaciones , Dolor/tratamiento farmacológico , Pautas de la Práctica en Medicina , Oncología por Radiación/estadística & datos numéricos , Analgésicos/administración & dosificación , Analgésicos/uso terapéutico , Análisis de Varianza , Antiinflamatorios/administración & dosificación , Antiinflamatorios/uso terapéutico , Humanos , Narcóticos/administración & dosificación , Narcóticos/uso terapéutico , Neoplasias/radioterapia , Dolor/etiología , Dolor/radioterapia , Análisis de Regresión , Encuestas y Cuestionarios
15.
Int J Radiat Oncol Biol Phys ; 44(5): 1027-38, 1999 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-10421535

RESUMEN

PURPOSE: To evaluate the rates of tumor downstaging after preoperative chemoradiation for locally advanced rectal cancer. MATERIALS AND METHODS: Preoperative chemoradiotherapy (CTX/XRT) that delivered 45 Gy in 25 fractions over 5 weeks with continuous infusion 5-fluorouracil (300 mg/m2/day) was given to 117 patients. The pretreatment stage distribution, as determined by endorectal ultrasound (u), included uT2N0 in 2%, uT3N0 in 47%, uT3N1 in 49%, and uT4N0 in 2% of cases; endorectal ultrasound was not performed in 13% of cases (15 patients). Approximately 6 weeks after completion of CTX/XRT, surgery was performed. RESULTS: The pathological tumor stages were Tis-2N0 in 26%, T2N1 in 5%, T3N0 in 21%, T3N1 in 15%, T4N0 in 5%, and T4NI in 1%; a complete response (CR) to preoperative CTX/XRT was pathologically confirmed in 32 (27%) of patients. Tumor downstaging occurred in 72 (62%) cases. Only 3% of cases had pathologic evidence of progressive disease. Pretreatment tumor size (< 5 cm vs. > or = 5 cm) was the only factor predictive of tumor downstaging (p < 0.04). A decrease of > 1 T-stage level was accomplished in 45% of those downstaged. Overall, a sphincter-saving (SP) procedure was possible in 59% of patients and an abdominoperineal resection (APR) was required in 41 % of cases. Factors predictive of SP included downstaging (p < 0.03), age > 40 years (p < 0.007), pretreatment tumor distance, 3 to 6 cm from the anal verge (p < 0.00001), tumor size <6 cm (p < 0.02), mobility (p < 0.004), tumor stage 6 cm from the anal verge, SP was performed in 14 of the 15 (93%) patients with a CR and 32 of 33 (97%) of patients with residual disease (p < 0.00004). CONCLUSIONS: Significant tumor downstaging results from preoperative chemoradiation allowing sphincter sparing surgery in over 40% of patients whose tumors were located < 6 cm from the anal verge and who otherwise would have required colostomy.


Asunto(s)
Canal Anal , Estadificación de Neoplasias , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Antimetabolitos Antineoplásicos/uso terapéutico , Terapia Combinada , Supervivencia sin Enfermedad , Femenino , Fluorouracilo/uso terapéutico , Humanos , Metástasis Linfática/patología , Masculino , Persona de Mediana Edad , Neoplasia Residual , Dosificación Radioterapéutica , Neoplasias del Recto/mortalidad , Neoplasias del Recto/patología , Neoplasias del Recto/cirugía
16.
Int J Radiat Oncol Biol Phys ; 47(3): 713-8, 2000 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-10837955

RESUMEN

RATIONALE: To evaluate the response to a concomitant boost given during standard chemoradiation for locally advanced rectal cancer. METHODS AND MATERIALS: Concomitant boost radiotherapy was administered preoperatively to 45 patients with locally advanced rectal cancer in a prospective trial. Treatment consisted of 45 Gy to the pelvis with 18 mV photons at 1.8 Gy/fraction using a 3-field belly board technique with continuous infusion 5FU chemotherapy (300mg/m(2)) 5 days per week. The boost was given during the last week of therapy with a 6-hour inter-fraction interval to the tumor plus a 2-3 cm margin. The boost dose equaled 7.5 Gy/5 fractions (1.5 Gy/fraction); a total dose of 52.5 Gy/5 weeks was given to the primary tumor. Pretreatment tumor stage, determined by endorectal ultrasound and CT scan, included 29 with T3N0 [64%], 11 T3N1, 1 T3Nx, 2 T4N0, 1 T4N3, and 1 with TxN1 disease. Mean distance from the anal verge was 5 cm (range 0-13 cm). Median age was 55 years (range 33-77 years). The population consisted of 34 males and 11 females. Median time of follow-up is 8 months (range 1-24 months). RESULTS: Sphincter preservation (SP) has been accomplished in 33 of 42 (79%) patients resected to date. Three patients did not undergo resection because of the development of metastatic disease in the interim between the completion of chemoradiation (CTX/XRT) and preoperative evaluation. The surgical procedures included proctectomy and coloanal anastomosis (n = 16), low anterior resection (n = 13), transanal resection (n = 4). Tumor down-staging was pathologically confirmed in 36 of the 42 (86%) resected patients, and 13 (31%) achieved a pathologic CR. Among the 28 tumors (67%) located <6 cm from the anal verge, SP was accomplished in 21 cases (75%). Although perioperative morbidity was higher, toxicity rates during CTX/XRT were comparable to that seen with conventional fractionation. Compared to our contemporary experience with conventional CTX/XRT (45Gy; 1.8 Gy per fraction), improvements were seen in SP (79% vs. 59%; p = 0.02), SP for tumors <6 cm from the anal verge (75% vs. 42%; p = 0.003), and down-staging (86% vs. 62%; p = 0.003). CONCLUSION: The SP rate with concomitant boost radiation has been highly favorable with rates of response which are higher than those previously reported for chemoradiation without administration of a boost. Further evaluation of this radiotherapeutic strategy appears warranted.


Asunto(s)
Antimetabolitos Antineoplásicos/uso terapéutico , Fluorouracilo/uso terapéutico , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/radioterapia , Adulto , Anciano , Canal Anal/cirugía , Terapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Metástasis Linfática , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Estudios Prospectivos , Dosificación Radioterapéutica , Neoplasias del Recto/cirugía
17.
Int J Radiat Oncol Biol Phys ; 49(1): 107-16, 2001 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-11163503

RESUMEN

PURPOSE: To assess pelvic chemoradiotherapy (CXRT) without colostomy as a component of the multidisciplinary management of patients presenting with metastatic rectal cancer. METHODS AND MATERIALS: Eighty patients with synchronous distant metastases from rectal cancer were treated with initial CXRT. Hypofractionated radiotherapy was administered usually with concurrent 5-FU (92%, 300 mg/m(2)/day, M-F). Three-field belly-board technique was used in 89%. Group 1 had CXRT alone (n = 55). Group 2 (n = 25) patients were selected for primary disease resection, and sometimes HAI chemotherapy (n = 10) or hepatic resection (n = 5). Subsequently, 78% received systemic chemotherapy. RESULTS: Symptoms from primary tumor resolved in 94%. Endoscopic complete clinical response rate was 36%. Two-year survival (11% vs. 46%, p < 0.0001) and symptomatic pelvic control (PC, 81% vs. 91%, p = 0.111) were higher in Group 2, but colostomy-free rate (CFR) was lower (79% vs. 51% p = 0.02). CFR was 87% in Group 1 patients managed initially without fecal diversion (n = 50). Examining all patients using multivariate analysis, pelvic pain at presentation (p < 0.00001), BED (biologic equivalent dose at 2 Gy/fraction) < 35 Gy (p = 0.077), and poor differentiation (0.079) predicted worse PC. Poor differentiation (p = 0.017) and selection for CXRT alone (p < 0.0001) predicted worse survival. There were 4 RTOG of Grade 3 or greater acute complications, 5 severe perioperative complications, and no significant late treatment-related complications. CONCLUSION: Durable PC can be safely achieved without colostomy in most patients presenting with primary rectal cancer and synchronous systemic metastases using hypofractionated pelvic chemoradiation. A BED greater than 35 Gy is recommended. Selected patients appear to benefit from resection of primary disease. Higher doses should be investigated in patients with pelvic pain.


Asunto(s)
Antimetabolitos Antineoplásicos/uso terapéutico , Fluorouracilo/uso terapéutico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/radioterapia , Neoplasias Pélvicas/tratamiento farmacológico , Neoplasias Pélvicas/radioterapia , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Estudios de Cohortes , Colostomía , Terapia Combinada , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Hemorragia Gastrointestinal/tratamiento farmacológico , Hemorragia Gastrointestinal/etiología , Hemorragia Gastrointestinal/radioterapia , Humanos , Infusiones Intravenosas , Obstrucción Intestinal/tratamiento farmacológico , Obstrucción Intestinal/etiología , Obstrucción Intestinal/radioterapia , Neoplasias Hepáticas/secundario , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias Pélvicas/secundario , Dosificación Radioterapéutica , Neoplasias del Recto/patología , Análisis de Supervivencia , Resultado del Tratamiento
18.
Int J Radiat Oncol Biol Phys ; 51(1): 176-83, 2001 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-11516868

RESUMEN

PURPOSE: To analyze the overall pattern of treatment failure and sites of pelvic disease recurrence relative to the radiation fields used in treating patients with clinically staged T4 rectal cancer with preoperative chemoradiation followed by multivisceral resection. METHODS AND MATERIALS: Between 1990 and 1998, 45 patients with T4 rectal cancer were treated with preoperative chemoradiation. Clinical staging was according to the system of the American Joint Cancer Committee and was based on endoscopic ultrasonography, chemotherapy (CT), and physical examination. A diagnosis of T4 disease required evidence of invasion of a contiguous structure on CT (n = 31) or endorectal ultrasonography (n = 6), vaginal mucosal involvement on pelvic examination (n = 6), or a combination of these findings (n = 2). Chemoradiation was delivered with 18 MV photons using a 3-field belly-board technique. The median total dose was 45 Gy in all patients (range 45-63). Nine patients received a boost with external beam radiotherapy (EBRT) (n = 5, 1.8-18 Gy), intraoperative RT (n = 3, 10-20 Gy), or interstitial brachytherapy (n = 1, 20 Gy). All patients received concurrent chemotherapy consisting of protracted venous infusion 5-fluorouracil (300 mg/m(2), 5 d/wk). Resection was not performed in 13 (29%) of the 45 patients because of metastases detected before resection or patient refusal. Multivisceral resection and pelvic exenteration was required in 21 (66%) and 11 (34%) of 32 patients, respectively. We compared the location of pelvic disease recurrence with the RT simulation films. The Kaplan-Meier method was used to calculate the 4-year actuarial pelvic and distant recurrent rates and the overall survival rate. RESULTS: The median length of follow-up was 31.0 months for all patients and 40.0 months for patients alive at last follow-up. When only the resected cases were considered, the local recurrence rate was 20%. Distant metastases occurred in 44% of cases; the overall survival rate was 69%. When all patients were considered, the local recurrence rate was similar (24%), but the rate of distant recurrence (51%) was higher and the overall survival rate lower (50%). Pelvic disease was controlled in all 8 patients whose disease responded well to chemoradiation (either a histologically complete response or microscopic residual disease). Three of 4 patients with close or positive margins had pelvic recurrences despite intraoperative RT and brachytherapy. Nine of the 10 pelvic recurrences occurred in the radiation field. Elective external iliac nodal irradiation was not used, and nodal metastases were not seen in that region. In 1 case, marginal recurrence occurred in a common iliac node at the superior edge of the treatment field. CONCLUSIONS: Despite aggressive multimodality therapy including multivisceral resection, a high rate of pelvic and distant disease recurrence occurred in patients with clinically staged T4 disease. Regional disease recurred almost exclusively in the radiation field. The intraoperative RT and interstitial brachytherapy doses used did not prevent pelvic disease recurrence in patients with close or positive margins. Novel strategies such as higher preoperative doses of RT with or without altered fractionation or more effective radiosensitizers are needed to improve locoregional control in patients with T4 disease. Future strategies must also include more effective systemic therapy.


Asunto(s)
Neoplasias del Recto/terapia , Adulto , Anciano , Anciano de 80 o más Años , Antimetabolitos Antineoplásicos/administración & dosificación , Quimioterapia Adyuvante , Terapia Combinada , Femenino , Fluorouracilo/administración & dosificación , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Complicaciones Posoperatorias/etiología , Radiodermatitis/patología , Dosificación Radioterapéutica , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/patología , Neoplasias del Recto/radioterapia , Neoplasias del Recto/cirugía , Análisis de Supervivencia , Insuficiencia del Tratamiento
19.
Int J Radiat Oncol Biol Phys ; 52(5): 1293-302, 2002 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-11955742

RESUMEN

PURPOSE: To retrospectively compare the toxicity and efficacy of concurrent gemcitabine-based chemoradiation with that of concurrent 5-fluorouracil (5-FU)-based chemoradiation in patients with unresectable pancreatic cancer. PATIENTS AND METHODS: Between September 1996 and May 2000, 114 patients with localized unresectable adenocarcinoma of the pancreas were treated with concurrent chemoradiation. Locally advanced unresectable disease was defined as low-density tumor in contact with the superior mesenteric artery (SMA) or celiac artery, or occlusion of the superior mesenteric-portal venous confluence. Fifty-three patients were selected to receive gemcitabine in 7 weekly cycles (250-500 mg/m(2)) with concurrent radiotherapy (median dose 30 Gy, range 30-33 Gy in 10-11 fractions). The remaining 61 patients received continuous-infusion 5-FU (200-300 mg/m(2)) with concurrent radiotherapy (30 Gy in 10 fractions). Radiotherapy was delivered to the primary tumor and regional lymphatics. Patients receiving gemcitabine and those receiving 5-FU had a similar mean Karnofsky performance status (KPS, 89% vs. 86%), distribution of tumor grade (43% vs. 33% poorly differentiated), and percent weight loss (all p = NS). However, patients treated with gemcitabine had a significantly larger median maximum cross-sectional tumor area (TA, 8.8 cm(2) vs. 5.7 cm(2), p = 0.046) and were significantly younger (median age 60 vs. 68 years, p <0.001). Severe acute toxicity (ST) was defined as toxicity requiring a hospital stay of more than 5 days, mucosal ulceration with bleeding, more than 3 dose deletions of gemcitabine or discontinuation of 5-FU, or toxicity resulting in surgical intervention or death. Kaplan-Meier analysis was used to calculate the actuarial rate of local progression on imaging (LP), the rate of distant metastasis (DM), and the overall survival (OS) rate. The imaging was reviewed in resected patients. RESULTS: Patients receiving gemcitabine developed significantly more ST during treatment (23% vs. 2%, p < 0.0001) than did those receiving 5-FU. Patients treated with gemcitabine had a similar 10-month LP rate (62% vs. 61%), 10-month DM rate (55% vs. 47%), 1-year OS rate (42% vs. 28%), and median OS duration (11 months vs. 9 months) to patients treated with 5 FU (all p = NS). Five patients who received gemcitabine and 1 patient who received 5-FU underwent margin-negative pancreaticoduodenectomy after chemoradiation. Three patients had a short segment (10 cm(2) (p = 0.03) and poor differentiation (p = 0.07) were associated with a worse survival duration; however, other factors, such as KPS and weight loss >10% and age did not influence OS. CONCLUSION: Despite the selection of healthier patients to receive gemcitabine, there was a significantly higher severe toxicity rate than with 5-FU. The median and 1-year survivals were not significantly different with the use of concurrent gemcitabine; however, the tumors treated were significantly larger. Additionally, a small number of patients with minimal arterial involvement whose disease met our radiographic definition of unresectable disease had margin-negative resections after treatment with gemcitabine-based chemoradiation. These possible benefits and the high rate of severe toxicity define a very narrow therapeutic index for concurrent gemcitabine-based chemoradiation given by this schedule of administration.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/radioterapia , Desoxicitidina/análogos & derivados , Desoxicitidina/uso terapéutico , Fluorouracilo/uso terapéutico , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/radioterapia , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Adenocarcinoma/cirugía , Adulto , Anciano , Terapia Combinada , Desoxicitidina/efectos adversos , Progresión de la Enfermedad , Femenino , Fluorouracilo/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Pancreáticas/cirugía , Pancreaticoduodenectomía , Fármacos Sensibilizantes a Radiaciones/efectos adversos , Estudios Retrospectivos , Análisis de Supervivencia , Gemcitabina
20.
Radiother Oncol ; 22(3): 195-200, 1991 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1771261

RESUMEN

Absence of a dose-response relationship has been reported for local control of Hodgkin's disease between 30 and 42 Gy delivered to the mantle field in definitive irradiation. These dose ranges were determined at the central ray using irregular field (IF) calculations without benefit of dosimetric correction for lung inhomogeneity. Detailed analysis was performed of dose delivered to hilar and mediastinal regions with mantle field irradiation incorporating lung inhomogeneity corrections for the indicated dose ranges using 60Co and 6 MV linear accelerator. Inclusion of lung inhomogeneity (LI) corrections revealed dose heterogeneity within the treatment volume, delivering higher total doses to hilar and lateral mediastinal regions. For a prescribed dose of 40 Gy to midline with 6 MV photons, the hila and mediastinum would receive 45 Gy with IF and LI corrections. Similar increases are observed with 60Co. Mantle field calculations should be performed with CT planning including lung inhomogeneity corrections to account for anatomic irregularity of the mediastinal contour and interposed lung. As lung inhomogeneity dosimetric data become available, conclusions drawn from clinical experience should be re-evaluated based upon location and extent of mediastinal disease involvement. Implications for treatment associated late toxicity using dose-volume histogram analysis should be considered.


Asunto(s)
Relación Dosis-Respuesta en la Radiación , Enfermedad de Hodgkin/radioterapia , Pulmón/efectos de la radiación , Traumatismos por Radiación/prevención & control , Dosificación Radioterapéutica , Radioisótopos de Cobalto/administración & dosificación , Radioisótopos de Cobalto/uso terapéutico , Humanos , Neoplasias Pulmonares/radioterapia , Neoplasias del Mediastino/radioterapia , Aceleradores de Partículas , Radiografía Torácica , Teleterapia por Radioisótopo , Tomografía Computarizada por Rayos X
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