RESUMO
Differential cross sections for electromagnetic fission of 238U projectiles (500 MeV/u) in C, Sn, and Pb targets are measured and analyzed in terms of single- and multiphonon giant resonance excitations as doorway states to fission. A novel experimental method exploits the linear relationship between neutron multiplicity and the primary 238U excitation energy. Multiphonon states contribute up to 20% of the cross section; a component at high excitation energies is indicated that may arise from three-phonon dipole and two-phonon GDR x GQRiv giant resonance excitations.
RESUMO
The role of radiation in endometrial cancer, especially in the adjuvant setting, is controversial. Factors that influence radiotherapy recommendations include surgical considerations, pathological findings, potential sites of disease recurrence and the practice philosophies of the individual physician. It has been demonstrated that adjuvant radiotherapy following primary surgery significantly improves pelvic tumour control, but has no measurable impact on overall survival in an unselected patient population. Studies to date have been hampered by the inclusion of patients with a wide spectrum of prognostic features; this may decrease the likelihood of observing greater benefit in discriminate subsets at higher risk of relapse. Further trials are required to define clinical prognosis more precisely and to investigate the role of radiation in higher-risk patients. In the meantime, we propose guidelines for radiotherapy in endometrial cancer which serve as bases for discussion and collaboration among physicians and as platforms for future study and progress.
Assuntos
Neoplasias do Endométrio/radioterapia , Braquiterapia/métodos , Neoplasias do Endométrio/patologia , Feminino , Humanos , Excisão de Linfonodo/métodos , Metástase Linfática/patologia , Metástase Linfática/radioterapia , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/radioterapia , Estadiamento de Neoplasias , Pelve , Prognóstico , Radioterapia Adjuvante , Ensaios Clínicos Controlados Aleatórios como Assunto , Terapia de Salvação/métodos , Neoplasias Vaginais/radioterapia , Neoplasias Vaginais/secundárioRESUMO
Although external beam radiation therapy is effective in the treatment of many pediatric brain neoplasms its use in this patient population has been associated with the development of significant cognitive and endocrine dysfunction and is severely limited as an option in previously irradiated patients. Therefore, we have adopted a strategy for management of residual microscopic disease by implantation of low-activity (125)I seeds in the tumor bed at the time of surgery. Six patients aged 2-14 years with recurrent tumors including two supratentorial primitive neuroectodermal tumors (n = 2), one medulloblastoma, one malignant ependymoma (n = 1), glioblastoma (n = 1) and one pleomorphic xanthoastrocytoma were implanted at the time of reoperation. A total of 11-126 seeds were implanted resulting in total doses of 16-21.8 Gy (after theoretical infinite time) at a depth of 5 mm from the implanted resection bed. Five patients had prior external beam radiation while the other patient (2 years old at initial diagnosis) progressed after surgery and chemotherapy. Two patients had lasting local tumor control. One patient is alive at 390 weeks of follow-up and another who died of distant failure at 366 weeks had no recurrence on MRI at 333 weeks' follow-up. Only 2 patients had first local failures. These results suggest that the use of permanent low-activity (125)I seeds as an adjunct to surgery can provide good local tumor control and is a suitable treatment option for pediatric patients.
Assuntos
Braquiterapia/efeitos adversos , Neoplasias Encefálicas/radioterapia , Radioisótopos do Iodo/farmacocinética , Radioisótopos do Iodo/uso terapêutico , Adolescente , Encéfalo/metabolismo , Encéfalo/patologia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/mortalidade , Criança , Pré-Escolar , Implantes de Medicamento , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Recidiva Local de Neoplasia , Dosagem Radioterapêutica , Resultado do TratamentoRESUMO
PURPOSE: The purpose of this study was to determine if radiotherapy is a beneficial adjuvant treatment after desmoid tumor resection. METHODS AND MATERIALS: A retrospective analysis was performed on 54 patients who underwent surgery without prior radiation at our institution between 1982 and 1998 to remove a desmoid tumor. Thirty-five patients had adjuvant radiation therapy after surgery, and 19 patients had surgery alone without immediate postoperative radiation. Sixteen of the 35 patients who underwent immediate postoperative radiation treatment had at least one prior resection before reoperation at our institution. Recurrence was defined as radiographic increase in tumor size after treatment. Follow-up interval (mean 39 months) and duration of local control were measured from the date of surgery at our institution. Potential prognostic factors for time to tumor progression were analyzed. RESULTS: Adjuvant treatment with radiation was the only significant prognostic factor for local control. The five-year actuarial local control rate was 81% for the 35 patients who underwent radiation in addition to surgery, compared to 53% for the 19 patients who underwent surgery alone (p = 0.018). For the patients who did not receive adjuvant radiation, only younger age at the time of surgery was associated with increased risk of failure (p = 0.035). Gross or microscopic margin status and number of prior operations were not detected as prognostic for local failure. For patients who did receive postoperative radiation, only abdominal location was associated with increased risk of failure (p = 0.0097). CONCLUSION: Radiation treatment as an adjuvant to surgery improved local control over surgery alone. Multiple operations before adjuvant radiation did not decrease the probability of subsequent tumor control. Radiation should be considered as adjuvant therapy to surgery if repeated surgery for a recurrent tumor would be complicated by a significant risk of morbidity.
Assuntos
Fibromatose Abdominal/radioterapia , Fibromatose Abdominal/cirurgia , Adulto , Análise de Variância , Feminino , Humanos , Masculino , Recidiva Local de Neoplasia , Radioterapia/efeitos adversos , Radioterapia Adjuvante , Estudos RetrospectivosRESUMO
Acute toxicity from radiation of skull base tumors typically resolves spontaneously within days to weeks after completion of therapy. Long-term complications have a latency of months to years after radiation and are usually irreversible. The need to keep the probability of chronic toxicity at an acceptable level has determined the upper limits of radiation doses for the treatment of tumors. The threat of chronic toxicity thus affects the ability to control skull base tumors with radiation. Use of conformal radiation techniques with image guidance, allowing minimization of normal tissue volume receiving significant radiation doses and close regulation of doses to specific structures, provides a low probability of long-term complications. Such conformal techniques may result in improved tumor control by allowing delivery of higher radiation doses to the tumor while maintaining an acceptable level of risk for chronic toxicity. Symptoms resulting from chronic radiation toxicity are indistinguishable from those due to tumor progression. In most cases in which radiation is used to treat tumors throughout the body, symptoms developing months after radiation are secondary to tumor recurrence and not due to toxicity from radiation. Notable exceptions are pituitary hormonal dysfunction after radiation for pituitary adenoma and cranial neuropathy after radiosurgery for vestibular schwannoma. With the recent evolution in radiosurgery techniques involving MR imaging guidance, decreased single doses in SRS, and fractionation of radiation dose in SRT, the probabilities of vestibular schwannoma progression and cranial nerve toxicity are approximately equal. Even in the case of visual field deficit after radiation therapy for a pituitary macroadenoma (for which the probability of tumor mass progression is only 5%-10%), the cause of the deficit is more likely to be progressive tumor than radiation-induced neuropathy. Consequently, diagnosis of a late-term radiation complication must be made only after verifying that the tumor has not progressed.
Assuntos
Irradiação Craniana/efeitos adversos , Lesões por Radiação/etiologia , Neoplasias da Base do Crânio/radioterapia , Encéfalo/efeitos da radiação , Nervos Cranianos/efeitos da radiação , Diagnóstico Diferencial , Progressão da Doença , Humanos , Hipotálamo/efeitos da radiação , Hipófise/efeitos da radiação , Lesões por Radiação/diagnóstico , Neoplasias da Base do Crânio/diagnósticoRESUMO
PURPOSE: To describe the design and commissioning of a system for the treatment of classes of tumors that require highly accurate target localization during a course of fractionated external-beam therapy. This system uses image-guided localization techniques in the linac vault to position patients being treated for cranial tumors using stereotactic radiotherapy, conformal radiotherapy, and intensity-modulated radiation therapy techniques. Design constraints included flexibility in the use of treatment-planning software, accuracy and precision of repeat localization, limits on the time and human resources needed to use the system, and ease of use. METHODS AND MATERIALS: A commercially marketed, stereotactic radiotherapy system, based on a system designed at the University of Florida, Gainesville, was adapted for use at the University of Washington Medical Center. A stereo pair of cameras in the linac vault were used to detect the position and orientation of an array of fiducial markers that are attached to a patient's biteblock. The system was modified to allow the use of either a treatment-planning system designed for stereotactic treatments, or a general, three-dimensional radiation therapy planning program. Measurements of the precision and accuracy of the target localization, dose delivery, and patient positioning were made using a number of different jigs and devices. Procedures were developed for the safe and accurate clinical use of the system. RESULTS: The accuracy of the target localization is comparable to that of other treatment-planning systems. Gantry sag, which cannot be improved, was measured to be 1.7 mm, which had the effect of broadening the dose distribution, as confirmed by a comparison of measurement and calculation. The accuracy of positioning a target point in the radiation field was 1.0 +/- 0.2 mm. The calibration procedure using the room-based lasers had an accuracy of 0.76 mm, and using a floor-based radiosurgery system it was 0.73 mm. Target localization error in a phantom was 0.64 +/- 0.77 mm. Errors in positioning due to couch rotation error were reduced using the system. CONCLUSION: The system described has proven to have acceptable accuracy and precision for the clinical goals for which it was designed. It is robust in detecting errors, and it requires only a nominal increase in setup time and effort. Future work will focus on evaluating its suitability for use in the treatment of head-and-neck cancers not contained within the cranial vault.
Assuntos
Neoplasias Encefálicas/radioterapia , Radiocirurgia/instrumentação , Planejamento da Radioterapia Assistida por Computador/instrumentação , Radioterapia Conformacional/instrumentação , Calibragem , Desenho de Equipamento , Estudos de Avaliação como Assunto , Humanos , Aceleradores de Partículas , Imagens de Fantasmas , Fenômenos Físicos , FísicaRESUMO
PURPOSE: To examine the efficacy of fast neutron radiotherapy for the treatment of locally advanced and/or recurrent adenoid cystic carcinoma of the head and neck and to identify prognostic variables associated with local-regional control and survival. METHODS AND MATERIALS: One hundred fifty-nine patients with nonmetastatic, previously unirradiated, locally advanced, and/or recurrent adenoid cystic carcinoma (ACC) of the head and neck region were treated with fast neutron radiotherapy during the years 1985-1997. One hundred fifty-one patients had either unresectable disease, or gross residual disease (GRD) after an attempted surgical extirpation. Eight patients had microscopic residual disease and were analyzed separately. Sixty-two percent of patients had tumors arising in minor salivary glands, 29% in major salivary glands, and 9% in other sites such as the lacrimal glands, tracheal-bronchial tree, etc. Fifty-five percent of patients were treated for postsurgical recurrent disease and 13% of patients had lymph node involvement at the time of treatment. The median duration of follow-up was 32 months (range 3-142 months). Actuarial curves for survival, cause-specific survival, local-regional control, and the development of distant metastases are presented for times out to 11 years. RESULTS: The 5-year actuarial local-regional tumor control rate for the 151 patients with GRD was 57%; the 5-year actuarial overall survival rate was 72%; and the 5-year actuarial cause-specific survival rate was 77%. Variables associated with decreased local-regional control in the patients with GRD as determined by multivariate analysis included base of skull involvement (p < 0.01) and biopsy only versus an attempted surgical resection prior to treatment (p = 0.03). Patients without these negative factors had an actuarial local-regional control rate of 80% at 5 years. Patients with microscopic residual disease (n = 8) had a 5-year actuarial local-regional control rate of 100%. Base of skull involvement (p < 0.001), lymph node metastases at the time of treatment (p < 0.01), biopsy only prior to neutron radiotherapy (p = 0.03), and recurrent tumors (p = 0.04) were found to be associated with a diminished cause-specific survival as ascertained by multivariate analysis. Patients with base of skull involvement and positive lymph nodes at presentation had an increased rate of the development of distant metastases at 5 years, (p < 0.01 and p < 0.001, respectively). No statistical difference in outcome was observed between major and minor salivary gland sites. CONCLUSIONS: Fast neutron radiotherapy is an effective treatment for locally advanced ACC of the head and neck region with acceptable toxicity. Further improvements in local-regional control are not likely to impact survival until more effective systemic agents are developed to prevent and/or treat distant metastatic disease.
Assuntos
Carcinoma Adenoide Cístico/radioterapia , Nêutrons Rápidos/uso terapêutico , Neoplasias de Cabeça e Pescoço/radioterapia , Análise de Variância , Carcinoma Adenoide Cístico/mortalidade , Carcinoma Adenoide Cístico/secundário , Feminino , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Taxa de SobrevidaRESUMO
The Syed template (Alpha-Omega Services, Bellflower, CA) has been established as an advance in interstitial gynecologic brachytherapy. Unfortunately, enthusiasm for the technique is often tempered by certain tumor geometries which require blind insertion of the interstitial needles, potentially risking inaccurate placement of the radioactive sources and viscus perforation. These concerns arise particularly in the management of anterior vaginal tumors where difficulties in negotiating the pubic arch can prevent optimal needle placement. In answer to this problem, a technique utilizing an open retropubic approach for Syed template interstitial implants in anterior vaginal tumors under direct visualization is described. To date, six procedures have been performed. The disease entities include advanced cervical squamous cell carcinoma, clear cell carcinoma of the vagina, recurrent vaginal carcinoma, recurrent endometrial carcinoma, and urethral adenocarcinoma. Complete response was noted in five of six patients but persistent local control of disease was achieved in only one of five complete responses over a relatively short follow-up interval. Complications included paravaginal abscess (n = 1), postoperative deep venous thrombosis (n = 1), abdominal incision cellulitis (n = 1), and radiation enteritis (n = 1). An open retropubic approach allows direct visualization of the bladder and urethra during interstitial implantation of anterior vaginal malignancies and facilitates negotiation of the pubic arch. In our experience, this technique results in improved needle positioning and is thus intuitively likely to aid in avoiding injury to surrounding normal tissues. Additional accrual of a larger cohort will be necessary to arrive at any meaningful objective conclusions regarding the technique's benefit over current modalities.
Assuntos
Braquiterapia/instrumentação , Braquiterapia/métodos , Neoplasias Vaginais/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Desenho de Equipamento , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
We describe a prototype digital radiotherapy simulator which consists of a conventional simulator gantry, digital spot imager, and image correction and reconstruction software. The ability of the digital spot imager to acquire a diagnostic quality image directly in digital format during simulation offers unique possibilities in clinical practice. Applications include prescription of multileaf collimator, on-line patient setup verification, remote consultation and treatment planning. In addition, we discuss the possibility of using the digital simulator as a volume-CT scanner capable of obtaining three-dimensional anatomical information in a single scan.
Assuntos
Simulação por Computador , Planejamento da Radioterapia Assistida por Computador/instrumentação , Sistemas Computacionais , Humanos , Processamento de Imagem Assistida por Computador , Sistemas On-Line , Imagens de Fantasmas , Radioterapia (Especialidade)/instrumentação , Intensificação de Imagem Radiográfica , Sistemas de Informação em Radiologia , Consulta Remota , Software , Tecnologia Radiológica/instrumentação , Tomografia Computadorizada por Raios X/métodosRESUMO
Primary tumor control remains a major problem in the treatment of locally advanced prostate carcinoma. Clinical local failure rates approach 30-40% and may be significantly higher when results of prostatic biopsy or prostate-specific antigen (PSA) levels are considered. The low growth rate and cycling fraction of prostate adenocarcinoma suggest potential therapeutic advantage for the high linear energy transfer (LET) of neutrons. The Radiation Therapy Oncology Group (RTOG) performed a multi-institutional randomized trial (RTOG 77-04) comparing mixed beam (neutron plus photon) irradiation to conventional photon irradiation for the treatment of locally advanced prostate cancer. A subsequent trial by the Neutron Therapy Collaborative Working Group (NTCWG 85-23) compared pure neutron irradiation to standard photon irradiation. Both randomized trials demonstrate significant improvement in locoregional control with neutron irradiation compared to conventional photon irradiation in the treatment of locally advanced prostate carcinoma. To date, only the mixed beam trial has shown a significant survival benefit. Future analysis of the larger NTCWG trial at the 10-year point should confirm whether or not improved locoregional control translates into a survival advantage. These findings have significant implications for all local treatment strategies including dose-escalated conformal photon irradiation, prostate implantation, and neutron radiation. Given the large numbers of patients afflicted with this disease, a positive survival advantage for neutrons or mixed beam therapy would provide a strong incentive for the development of economically feasible clinical neutron facilities.
Assuntos
Adenocarcinoma/radioterapia , Nêutrons Rápidos/uso terapêutico , Neoplasias da Próstata/radioterapia , Adenocarcinoma/mortalidade , Humanos , Masculino , Neoplasias da Próstata/mortalidade , Ensaios Clínicos Controlados Aleatórios como Assunto , Taxa de SobrevidaRESUMO
OBJECTIVE: Earlier studies have demonstrated that the uterine papillary serous carcinoma (UPSC) variant of endometrial carcinoma has a high recurrence rate, even when disease is apparently confined to the uterus. The current study evaluated survival in patients with surgically staged UPSC. METHODS: Patients with UPSC were identified from surgical pathology files and charts were retrospectively reviewed. Only patients who had undergone a TAH-BSO, lymph node dissection, and peritoneal cytology were included. RESULTS: The FIGO stages of the 36 patients were 12 Stage I (4 IA, 4 IB, 4 IC), 2 Stage IIB, 13 Stage III (5 IIIA, 8 IIIC), and 9 Stage IV. Of the 14 Stage I/II patients, 6 did not receive adjuvant therapy, 5 received whole pelvic radiation (WPXRT), and 3 received whole abdominal radiation therapy (WART); after a median follow-up interval of 50 months only 2 (14%) of these Stage I/II patients have developed a recurrence. Both of the recurrences were in Stage IC patients who received radiation; 1 recurred in the radiation field. Of the 5 Stage IIIA patients, 3 patients declined therapy and 2 were treated with WART; 3 patients, including the 2 who received radiation therapy, are alive without disease. Of the 8 Stage IIIC patients, 2 declined postoperative therapy, 2 received WART, and 4 received WPXRT with an extended field to include paraaortic nodes. Four of the 6 Stage IIIC patients treated with curative intent are without evidence of disease and 1 died of unrelated causes after a median follow-up interval of 48 months. Both of the Stage IIIC patients who declined treatment recurred. Of the 9 patients with Stage IV disease, 8 have died of disease. CONCLUSION: Women with UPSC have a good prognosis when surgical staging confirms that disease is confined to the uterus (Stage I/II). Surgical findings can also be used to tailor adjuvant radiation treatments. Further study is required to define the optimal treatment for women with metastatic UPSC.
Assuntos
Cistadenocarcinoma Papilar/patologia , Neoplasias Uterinas/patologia , Idoso , Idoso de 80 Anos ou mais , Cistadenocarcinoma Papilar/mortalidade , Cistadenocarcinoma Papilar/cirurgia , Feminino , Procedimentos Cirúrgicos em Ginecologia/métodos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida , Neoplasias Uterinas/mortalidade , Neoplasias Uterinas/cirurgiaRESUMO
PURPOSE: The primary objectives of the study were to evaluate the efficacy and safety of prolonged oral (PO) etoposide as part of cisplatin-based chemotherapy plus concurrent chest/brain irradiation induction, followed by CAV consolidation, in the treatment of patients with limited-stage small cell lung cancer (SCLC-LD) within a cooperative group setting. METHODS AND MATERIALS: Fifty-six eligible patients with SCLC-LD received three 28-day cycles of cisplatin 50 mg/m2 i.v. (days 1, 8; 29, 36; and 57, 64), PO etoposide 50 mg/m2 (days 1-14, 29-42, and 57-70), and vincristine 2 mg i.v. (days 1, 29, and 57). Thoracic irradiation (TRT) was administered at 1.8 Gy in 25 daily fractions to a total dose of 45 Gy via an AP:PA arrangement, to begin concomitantly with induction chemotherapy. Prophylactic cranial irradiation (PCI) was started on day 15 of induction therapy. Fifteen daily fractions of 2.0 Gy were administered to the entire brain to a total dose of 30 Gy to finish at approximately the same time as TRT. Two 21-day cycles of consolidation cyclophosphamide 750 mg/m2 i.v., doxorubicin 50 mg/m2 i.v., and vincristine 2 mg i.v. (all on days 1 and 22), were given beginning on day 106 or week 16, from the start of induction therapy. RESULTS: Among 56 eligible patients, 93% had SWOG performance status 0-1. All had adequate organ function and had not received prior therapy. The overall confirmed response rate was 46%, including 16% complete responders and 30% partial responders. After a minimum follow-up duration of 17 months, the Kaplan-Meier median progression-free (PFS) and overall survival (OS) were 10 and 15 months, respectively. Two-year survival is 28%. Only 28 of 56 patients (50%) completed chemotherapy per protocol, while 52 of 56 patients (93%) completed radiation per protocol. Eleven patients (20%) discontinued secondary to toxicity and two patients died from treatment. The major toxicity was hematologic. The two deaths were secondary to infection. Of the nonhematologic toxicities, there were 10 cases of pulmonary fibrosis (including one Grade 3) and six cases of pneumonitis (including one Grade 3). CONCLUSION: Concomitant chemoradiation with oral etoposide as part of a platinum-based chemotherapy and TRT induction regimen is toxic. The CR rate is not better than our prior best group-wide experience. The progression-free and overall survival are similar to published trials utilizing short-course i.v. etoposide. As in chemotherapy for extensive-stage SCLC, there is no apparent advantage to prolonged exposure to etoposide, and toxicity resulted in an inferior therapeutic index compared to programs with shortened exposure.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Pequenas/tratamento farmacológico , Carcinoma de Células Pequenas/radioterapia , Irradiação Craniana , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Administração Oral , Adulto , Idoso , Carcinoma de Células Pequenas/mortalidade , Cisplatino/administração & dosagem , Terapia Combinada , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Etoposídeo/administração & dosagem , Feminino , Seguimentos , Humanos , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Análise de Sobrevida , Vincristina/administração & dosagemRESUMO
Both fast neutron radiotherapy and boron neutron capture therapy have been investigated as new radiation treatment techniques for patients with malignant gliomas. While each of these techniques individually has shown the potential for pathological eradication of malignant glioma, to date neither has evolved into an accepted, improved method of treatment. We have recently begun a research program investigating the feasibility of combining the benefits of both types of therapy. As a fast neutron beam penetrates tissue some of the particles are degraded to thermal energies. These can be captured by 10B or other suitable isotopes resulting in a highly-localized release of additional energy during a course of fast neutron radiotherapy. In this article we will review the rationale for such an approach, and review the underlying physics as well as in vitro, in vivo, and early human studies testing its feasibility. If appropriate carrier agents can be found that preferentially-localize in tumor cells, this approach ena be applied to many different tumor systems.
Assuntos
Terapia por Captura de Nêutron de Boro , Neoplasias Encefálicas/radioterapia , Glioma/radioterapia , Animais , Boro , Linhagem Celular , Sobrevivência Celular/efeitos da radiação , Cricetinae , Cricetulus , Nêutrons Rápidos , Estudos de Viabilidade , Humanos , Isótopos , RatosRESUMO
A comparison was made of different treatment plans to determine the effect on the three-dimensional dose distributions of varying the allowed parameters in linac-based stereotactic radiosurgery with circular collimators; these parameters are arc position, length, and weighting, and collimator diameter. For the class of eccentrically shaped target volumes that are not so irregular as to require several separate isocenters, it was found that superior dose distributions could be achieved by varying arc length, arc position, arc weighting, and collimator diameter. An analysis of the results achieved with an automated planning program indicates that, in general, the variables of arc position and arc length are of greater importance than collimator size or beam weighting. However, there are cases where varying these latter two parameters does result in markedly better dose distributions. A deeper investigation into the effects of multiple collimators on the dose distribution in the area of steepest gradient demonstrated that multiple collimator sizes do not significantly degrade the dose falloff, which is in fact mostly determined by the effects of intersecting arcs.
Assuntos
Neoplasias Encefálicas/cirurgia , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador , Radioterapia Assistida por Computador , Neoplasias Encefálicas/secundário , Humanos , Estudos RetrospectivosRESUMO
Twenty-two adult patients with recurrent high grade astrocytomas [18 glioblastoma multiforme (GBM) and 4 anaplastic astrocytoma (AA) at time of implant] underwent therapy at the University of Washington from October 1991 through March 1995, with repeat craniotomy, maximal debulking of tumor, and placement of permanent low activity 125I seeds. Median age was 41 years and median Karnofsky performance status was 90. Median survival for the entire group was 65 weeks from the time of implant. For the subgroup of GBM patients, median survival was 64 weeks from the time of implant. One-year survival from the date of implant was 57% for the entire group and 59% for those with GBM. The site of first failure after implant was local (within 2 cm of the resection cavity) in 70%, distant (noncontiguous, beyond 2 cm) in 18% and concurrently local and distant in 12%. There was one case of symptomatic radiation injury that resolved with steroid therapy, and no patient required repeat craniotomy for parenchymal necrosis. For patients with recurrent GBM, treatment with resection and permanent low activity 125I brachytherapy yielded improved survival compared to an internal historical control group treated with resection and chemotherapy (p = 0.023). Craniotomy with maximal tumor debulking and placement of low activity 125I seeds yields encouraging results with minimal morbidity in patients with recurrent high-grade astrocytomas.
Assuntos
Braquiterapia , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/cirurgia , Glioblastoma/radioterapia , Glioblastoma/cirurgia , Radioisótopos do Iodo/uso terapêutico , Recidiva Local de Neoplasia/radioterapia , Recidiva Local de Neoplasia/cirurgia , Adolescente , Adulto , Idoso , Terapia Combinada , Humanos , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Estudos Retrospectivos , Análise de Sobrevida , Falha de TratamentoRESUMO
Hematuria is a common clinical problem. It may arise from benign diseases posing minimal risk to the patient to potentially life-threatening conditions. Due to its many causes, the evaluation of hematuria often requires various different diagnostic procedures. To prevent unnecessary diagnostic tests, the workup should begin with noninvasive techniques such as history, urinalysis, laboratory data and ultrasonography. This proceeding allows a simple and rapid differentiation in renal and non-renal causes of hematuria in most cases.
Assuntos
Hematúria/etiologia , Acantócitos , Diagnóstico Diferencial , Glomerulonefrite/complicações , Glomerulonefrite/diagnóstico , Glomerulonefrite/terapia , Hematúria/diagnóstico , Hematúria/terapia , Humanos , Nefropatias/complicações , Nefropatias/diagnóstico , Nefropatias/terapiaRESUMO
OBJECTIVE: Recent anatomic and radiographic studies have indicated that standard external beam radiation portals may not adequately treat the volume at risk in patients with local-regionally advanced cervical cancer. A feasibility study was undertaken to evaluate toxicity, outcome, and patterns of failure in patients with advanced cervical cancer treated by expanded pelvic radiation fields. STUDY DESIGN: Thirty-eight women with stages IIB and III cancers of the cervix confined to the pelvis were irradiated with curative intent with expanded pelvic radiation portals. Anteriorly and posteriorly, the median field length and width were 20 and 17.5 cm, respectively. Lateral fields had a median width of 16.5 cm, and the posterior border encompassed the entire sacral silhouette. The median external beam whole-pelvis dose was 4140 cGy, with overall point A dose boosted by brachytherapy to 8315 cGy. RESULTS: Stage IIB patients (n = 22) had a 4-year actuarial local control rate of 70%, freedom from distant metastases rate of 62%, and disease-specific survival rate of 76%. In stage III disease (n = 16), the 4-year actuarial local control, freedom from distant metastases, and disease-specific survival rates were 80%, 48%, and 53%, respectively. Radiographically determined nodal status was an important predictor of disease-specific survival and distant metastases but not local control. The 4-year disease-specific survival rate was 40% in 11 patients with nodal disease compared with 71% in 27 node-negative patients (p < 0.01). The rate of freedom from distant metastases was 36% in node-positive patients versus 67% in node-negative cases (p < 0.01). The actuarial overall 4-year severe late complication rate was 14.8%. CONCLUSION: This study has demonstrated that expanded fields for pelvic radiotherapy is feasible, well tolerated, and therapeutic. The pelvic field design concepts presented should be integrated into radiation oncology practice.
Assuntos
Neoplasias do Colo do Útero/radioterapia , Antineoplásicos/uso terapêutico , Braquiterapia , Terapia Combinada , Feminino , Humanos , Linfonodos/diagnóstico por imagem , Metástase Linfática , Metástase Neoplásica/prevenção & controle , Estadiamento de Neoplasias , Pelve , Radiografia , Taxa de Sobrevida , Falha de Tratamento , Neoplasias do Colo do Útero/mortalidade , Neoplasias do Colo do Útero/patologiaRESUMO
The development of clinical neutron facilities in the 1980s, capable of delivering high energy neutrons spurred full scale phase III testing of neutron beam radiotherapy in a number of tumors including salivary gland, head and neck, prostate, and non small-cell lung cancer. The Radiation Therapy Oncology Group (RTOG) and the Medical Research Council (MRC) jointly sponsored a randomized trial for the treatment of advanced stage salivary gland tumors comparing neutron to conventional photon and/or electron radiotherapy. Although no improvement in survival was seen, the study demonstrated a striking and statistically significant difference in the local-regional control of unresectable salivary gland tumors (56 vs 17%), favoring neutron beam irradiation. Subsequent clinical trials of neutron beam irradiation were initiated by the Neutron Therapy Collaborative Working Group (NTCWG) sponsored by the National Cancer Institute (NCI). A phase III trial comparing neutron to photon radiotherapy for inoperable regional non-small cell lung cancer showed no overall improvement in survival. However, a statistically significant improvement in survival was observed in the subset of patients with squamous cell histology. The NTCWG trial comparing fast-neutron therapy versus conventional photon irradiation in the treatment of advanced squamous cell carcinomas of the head and neck showed a statistically significant improvement in initial complete response (70 vs 52%) favoring neutrons. However, subsequent failures erased any difference in ultimate local-regional control rates and survival curves were essentially the same in both arms. The randomized study of the NTCWG for locally advanced prostate cancer demonstrated a significant decrease in local-regional failure (11 vs 32%) at 5 years, favoring the neutron arm. Furthermore, biochemical measures of disease control also favored the neutron arm with prostate specific antigen (PSA) levels elevated in 17% of the neutron-treated patients compared to 45% of the photon-treated patients at 5 years. At the 5-year analysis, no significant difference in survival was observed between the two arms; however, longer follow-up is necessary to assess the ultimate impact of improved local-regional control on survival. An analysis of complications in this series revealed the importance of beam shaping and treatment planning capabilities in maintaining long-term sequelae following neutron irradiation at an acceptably low level.