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1.
Curr Treat Options Oncol ; 23(12): 1761-1774, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36333623

RESUMO

OPINION STATEMENT: Patients with hepatocellular carcinoma (HCC) with underlying Child-Pugh B-7 cirrhosis benefit from management from an experienced, multidisciplinary team. In patients with localized disease who meet criteria for liver transplant, establishing care at a liver transplant center is crucial. For those awaiting transplant, local bridge therapies have emerged as a strategy to maintain priority status and eligibility. Multiple liver-directed therapies exist to provide locoregional tumor control. The careful selection of locoregional therapy is a multidisciplinary endeavor that takes into account patient factors including tumor resectability, underlying liver function, performance status, previous treatment, tumor location/size, and vascular anatomy to determine the optimal management strategy. Technological advances in external beam radiation therapy have allowed stereotactic body radiation therapy (SBRT) to emerge in recent years as a versatile and highly effective bridge therapy consisting of typically between 3 and 5 high dose, highly focused, and non-invasive radiation treatments. When treating cirrhotic patients with HCC, preserving liver function is of utmost importance to prevent clinical decline and decompensation. SBRT has been shown to be both safe and effective in carefully selected patients with Child-Pugh B cirrhosis; however, care must be taken to prevent radiation-induced liver disease. This review summarizes the evolving role of SBRT in the treatment of HCC in patients with Child-Pugh B-7 cirrhosis.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Lesões por Radiação , Radiocirurgia , Humanos , Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/radioterapia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/patologia , Radiocirurgia/efeitos adversos , Estudos Retrospectivos , Cirrose Hepática/complicações , Lesões por Radiação/etiologia , Resultado do Tratamento
3.
Adv Radiat Oncol ; 6(1): 100559, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33665482

RESUMO

PURPOSE: For patients with hepatocellular carcinoma awaiting liver transplantation (LT), stereotactic body radiation therapy (SBRT) has emerged as a bridging treatment to ensure patients maintain priority status and eligibility per Milan criteria. In this study, we aimed to determine the efficacy and safety of SBRT in such situations. METHODS AND MATERIALS: A retrospective analysis was conducted of the outcomes of 27 patients treated with SBRT who were listed for LT at 1 institution. Among these, 20 patients with 26 tumors went on to LT and were the focus of this study. Operative reports and postoperative charts were evaluated for potential radiation-related complications. The explant pathology findings were correlated with equivalent dose in 2 Gy fractions and tumor size. RESULTS: Median pretreatment tumor size was 3.05 cm. Median total dose of radiation was 50 Gy delivered in 5 fractions. Pathologic complete response (pCR) was achieved in 16 tumors (62%). Median interval from end of SBRT to transplant was 287 days. Of the 21 tumors imaged before transplant, 16 or 76% demonstrated a clinical complete response based on modified Response Evaluation Criteria in Solid Tumors criteria. There was no significant correlation between pCR rate and increasing tumor size (odds ratio [OR], 0.95; 95% confidence interval, 0.595-1.53) or pCR rate and equivalent dose in 2 Gy fractions (OR, 1.03; 95% confidence interval, 0.984-1.07.) No patients experienced radiation-related operative or postoperative complications. Of the 27 patients who were listed for transplant, the dropout rate was 22%. Two of the 5 patients with Child-Pugh score 10 died of liver failure. CONCLUSIONS: These data demonstrate that SBRT as a bridging modality is a feasible option, with a pCR rate comparable to that of other bridging modalities and no additional radiation-related operative or postoperative complications. There was no dose dependence nor size dependence for pCR rate, which may indicate that for the tumor sizes in this study, the radiation doses delivered were sufficiently high.

4.
Adv Radiat Oncol ; 5(5): 889-896, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33083650

RESUMO

PURPOSE: Our purpose was to report outcomes in patients with Child-Pugh B or C (CP B/C) hepatocellular carcinoma (HCC) treated with stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: Patients with HCC suitable for SBRT were prospectively enrolled in the study from 2012 to 2018. Outcomes in patients with CP B/C were analyzed. Cox proportional hazard models were used to compare survival outcomes between baseline CP score and post-SBRT CP score. RESULTS: Twenty-three patients with CP B/C with a total of 29 HCC tumors were treated with SBRT. Eighty-seven percent of patients were CP B8-C10. Median tumor size was 3.1 cm (range, 1-10 cm). Median dose delivered was 40 Gy in a median of 5 fractions. Eighteen of 23 patients (78.3%) had been previously treated with transarterial chemoembolization. Median follow-up was 14.5 months. Rates of 6- and 12-month local control were 100% and 92.3%, respectively. Six- and 12-month survival rates were 73.9% and 56.5%, respectively. Median survival was 14.5 months overall and 9.2, 22.5, 14.5, and 14.4 months for patients with CP B7, B8, B9, and C10, respectively. No patients exhibited symptoms of classic radiation-induced liver disease. However, 10 patients had CP score progression, with 4 patients (17%) having a ≥2-point increase in CP score by 6 months (or time of censor). There were 7 liver-related deaths, and based on independent review by a hepatologist, 1 of these deaths may have been attributable to SBRT-related liver injury. Fifteen of 23 patients were listed for liver transplant (LT) at the time of SBRT and 9 went on to receive LT with a pathologic complete response rate of 63.6%. Median survival, excluding patients who received LT, was 7.3 months. CONCLUSIONS: SBRT is a reasonable treatment option for carefully selected patients with CP B7-C10. In our small cohort, there was no detectable difference between local control or overall survival and baseline CP score.

5.
Pract Radiat Oncol ; 10(5): e348-e356, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31866576

RESUMO

PURPOSE: The role of surgical clips as markers of the tumor bed cavity for radiation therapy boost targeting after oncoplastic surgery is not well understood. Therefore, we sought to evaluate whether the placement of surgical clips can reduce interobserver variability in the delineation of the tumor bed cavities of oncoplastic surgery patients and ultimately determine an optimal number of clips to place. METHODS AND MATERIALS: We reviewed records of 39 women with breast cancer who underwent oncoplastic breast surgery and adjuvant radiation therapy at our institution. Three radiation oncologists contoured tumor bed cavity volumes on planning computed tomography simulation images. Interobserver variability was measured both by a coefficient of variation of radiation oncologists contour volume and a concordance index defined as the quotient of the intersecting and aggregated volume of the contours. Patients were stratified by the number of surgical clips placed and compared by 1-way analysis of variance. Simple linear regression was used to evaluate the relationship of total excised volume and interobserver variability in patients with a sufficient quantity of surgical clips. RESULTS: Interobserver variability in the delineation of the tumor bed cavity as measured by concordance index was significantly reduced in patients who received intraoperative surgical clips (F = 5.755; P = .001). A similar trend was seen in contour volume (F = 2.616; P = .052). Results of 1-way analysis of variance and post hoc analysis showed that 4 clips are effective and sufficient for reproducible delineation of the tumor bed cavity for the radiation therapy boost. Increasing excision volume does not result in an increase in interobserver variability (r2 = 0.00003). CONCLUSIONS: In oncoplastic surgery patients, intraoperative placement of surgical clips is beneficial and effective in improving the delineation of the tumor bed cavity for the radiation therapy boost. Four clips are necessary and sufficient for accurate boost targeting after lumpectomy with oncoplastic reconstruction.


Assuntos
Neoplasias da Mama , Instrumentos Cirúrgicos , Mama , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/radioterapia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Mastectomia Segmentar , Radioterapia Adjuvante , Carga Tumoral
6.
Clin Transl Radiat Oncol ; 4: 15-23, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29594203

RESUMO

INTRODUCTION: Radiation therapy is crucial to effective cancer treatment. Modern treatment strategies have reduced possible skin injury, but few clinical studies have addressed the dose relationship between radiation exposure and skin reaction. This prospective clinical study analyzes skin oxygenation/perfusion in patients undergoing fractionated breast conserving therapy via hyperspectral imaging (HSI). METHODS: Forty-three women undergoing breast conserving therapy were enrolled in this study. Optically stimulated luminescent dosimeters (OSLDs) measured radiation exposure in four sites: treatment breast, lumpectomy scar, medial tattoo and the control breast. The oxygenation/perfusion states of these sites were prospectively imaged before and after each treatment fraction with HSI. Visual skin reactions were classified according to the RTOG system. RESULTS: 2753 observations were obtained and indicated a dose-response relationship between radiation exposure and oxygenated hemoglobin (OxyHb) after a 600 cGy cumulative dose threshold. There was a relatively weak association between DeoxyHb and radiation exposure. Results suggest strong correlations between changes in mean OxyHb and skin reaction as well as between radiation exposure and changes in skin reaction. CONCLUSION: HSI demonstrates promise in the assessment of skin dose as well as an objective measure of skin reaction. The ability to easily identify adverse skin reactions and to modify the treatment plan may circumvent the need for detrimental treatment breaks.

7.
Clin Imaging ; 40(6): 1131-1134, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27474913

RESUMO

PURPOSE: This study aims to evaluate the recurrence pattern of hepatocellular carcinoma (HCC) following liver transplantation. MATERIALS AND METHODS: A total of 54 patients underwent liver transplantation for HCC; 9 patients developed biopsy-proven recurrent HCC (16.6%). The site of HCC recurrence along with other factors was analyzed. RESULTS: Seven patients were diagnosed with HCC prior to liver transplantation and 2 patients had incidental HCC in the explanted liver. Two patients had locoregional recurrence, 4 patients had distant metastasis, and 3 patients had synchronous locoregional recurrence and distant metastasis. CONCLUSION: A significant proportion of HCC recurrence following liver transplantation is extrahepatic.


Assuntos
Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/cirurgia , Transplante de Fígado , Recidiva Local de Neoplasia/diagnóstico , Complicações Pós-Operatórias/diagnóstico , Adulto , Idoso , Algoritmos , Carcinoma Hepatocelular/diagnóstico , Feminino , Humanos , Achados Incidentais , Neoplasias Hepáticas/diagnóstico , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
8.
Adv Radiat Oncol ; 1(3): 141-147, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28740883

RESUMO

OBJECTIVE: Our objective was to report safety and efficacy of stereotactic radiosurgery (SRS) to the surgical bed following resection of brain metastases. METHODS: Eighty-seven consecutive patients who underwent cavity-directed SRS to the operative bed for the treatment of brain metastases between 2002 and 2010 were evaluated. SRS required a gadolinium-enhanced, high-resolution, T1-weighted magnetic resonance imaging for tumor targeting and delivered a median dose of 18 Gy (14-22 Gy) prescribed to encompass the entire resection cavity. Whole brain irradiation was reserved for salvage. Patients were followed every 3 months with clinical examination and magnetic resonance imaging. Overall survival, local and regional recurrence, and factors affecting these outcomes were evaluated using Kaplan-Meier and log-rank analyses. RESULTS: The median imaging follow-up was 7.1 months, with >40% of patients having imaging for ≥1 year. Local control at 1 and 2 years was 82% and 75%, respectively. Cavity recurrence was more common with a tumor diameter >3 cm (P < .020) or resection cavity volume >14 mL (P < .050). One-year local control for tumors <2 cm, 2 cm to 3 cm, and >3 cm were 100%, 86%, and 72%, respectively. Neither subtotal resection nor target margins >2 mm to 3 mm affected local control. The median overall survival was 14.3 months with actuarial 5-year survival of 20%. Actuarial regional central nervous system recurrence was 44% at 1 year. On univariate analysis, only the presence of extracranial disease was associated with survival (P < .001) and central nervous system failure (P < .030). CONCLUSIONS: Excellent local control is achievable with cavity-directed SRS in well-selected patients, particularly for lesions with diameter <3 cm and resection cavity volumes <14 mL. Long-term survival is possible for select patients.

9.
Brachytherapy ; 14(4): 496-501, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25900392

RESUMO

PURPOSE: Noninvasive image-guided breast brachytherapy (NIBB) is an attractive novel approach to deliver accelerated partial breast irradiation (APBI). Calculations of equivalent uniform dose (EUD) were performed to identify the appropriate APBI dose for this technique. METHODS AND MATERIALS: APBI plans were developed for 15 patients: five with three-dimensional conformal APBI (3D-CRT), five with multi-lumen intracavitary balloons (m-IBB), and five simulating NIBB treatment. Prescription doses of 34.0 and 38.5 Gy were delivered in 10 fractions for m-IBB and 3D-CRT, respectively. Prescription doses ranging from 34.0 to 38.5 Gy were considered for NIBB. Dose-volume histogram data from all 3D-CRT, m-IBB, and NIBB plans were used to calculate the biologically effective EUD and corresponding EUD to the PTV_eval using the following equation: EUD = EUBED/(n [1 + EUD/α/ß]). An α/ß value of 4.6 Gy was assumed for breast tumor. EUD for varying NIBB prescription doses were compared with EUD values for the other APBI techniques. RESULTS: Mean PTV_eval volume was largest for 3D-CRT (372.9 cm(3)) and was similar for NIBB and m-IBB (88.7 and 87.2 cm(3), respectively). The EUD value obtained by prescribing 38.5 Gy with 3D-CRT APBI was 38.6 Gy. The EUD value of 34.0 Gy prescribed with m-IBB was 34.4 Gy. EUD values for NIBB ranged from 33.9 to 38.2 Gy for prescription doses ranging from 34.0 to 38.5 Gy. CONCLUSIONS: Using EUD calculations to compare APBI techniques and treatment doses, a prescription dose of 36.0 Gy in 10 fractions using NIBB has a comparable biologic equivalent dose to other established brachytherapy techniques.


Assuntos
Braquiterapia/métodos , Neoplasias da Mama/radioterapia , Adulto , Fracionamento da Dose de Radiação , Feminino , Humanos , Dosagem Radioterapêutica , Radioterapia Conformacional/métodos
10.
Pract Radiat Oncol ; 5(1): e37-44, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25413429

RESUMO

PURPOSE: Stereotactic radiosurgery (SRS) represents a treatment option for patients with brain metastases from small cell lung cancer (SCLC) following prior cranial radiation. Inferior local control has been described. We reviewed our failure patterns following SRS treatment to evaluate this concern. METHODS AND MATERIALS: Individuals with SCLC who received SRS for brain metastases from 2004 to 2011 were identified. Central nervous system (CNS) disease was detected and followed by gadolinium-enhanced, high-resolution magnetic resonance (MR) imaging. SRS dose was prescribed to the tumor periphery. Local recurrence was defined by increasing lesion size or enhancement, MR-spectroscopy, and perfusion changes consistent with recurrent disease or pathologic confirmation. Any new enhancing lesion not identified on the SRS planning scan was considered a regional failure. Overall survival (OS) and CNS control were evaluated using the Kaplan-Meier method. Factors predicted to influence outcome were tested by univariate log-rank analysis and Cox regression. RESULTS: Fifteen males and 25 females (median age of 61 years [range, 36-79]) of which 39 received prior brain irradiation were identified. In all, 132 lesions (3.3 per patient) between 0.4 and 4.7 cm received a median dose of 16 Gy (12-22 Gy). Thirteen metastases (10%) ultimately recurred locally with 6- and 12-month control rates of 81% and 69%, respectively. Only 1 of 110 metastases <2 cm recurred. Local failure was more likely for size >2 cm (P < .001) and dose <16 Gy (P < .001). The median OS was 6.5 months, and the time to regional CNS recurrence was 5.2 months. For patients with single brain metastases, both OS (P = .037) and regional CNS recurrence (P = .003) were improved. CNS control (P = .001), and survival (P = .057), were also longer for patients with controlled systemic disease. CONCLUSIONS: Local control following SRS for SCLC metastases is achievable for lesions <2 cm. For metastases >2 cm, local failure is more common than expected. Patients with controlled systemic disease and limited CNS involvement would benefit most from aggressive treatment.


Assuntos
Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/cirurgia , Neoplasias Pulmonares/patologia , Radiocirurgia/métodos , Carcinoma de Pequenas Células do Pulmão/secundário , Carcinoma de Pequenas Células do Pulmão/cirurgia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/diagnóstico , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
12.
J Neurosurg ; 119(2): 457-62, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23662828

RESUMO

OBJECT: The goal of this study was to evaluate outcomes in patients with ≥ 10 CNS metastases treated with Gamma Knife stereotactic radiosurgery (GK-SRS). METHODS: Patients with ≥ 10 brain metastases treated using GK-SRS during the period between 2004 and 2010 were identified. Overall survival and local and regional control as well as necrosis rates were determined. The influence of age, sex, histological type, extracranial metastases, whole-brain radiation therapy, and number of brain metastases was analyzed using the Kaplan-Meier method. Univariate (log-rank) analyses were performed, with a p value of < 0.05 considered significant. RESULTS: Fifty-three patients with ≥ 10 brain metastases were treated between 2004 and 2010. All had a Karnofsky Performance Status score of ≥ 70. Seventy-two percent had either non-small cell lung cancer (38%) or breast cancer (34%); melanoma, small cell lung cancer, renal cell carcinoma, and testicular, colon, and ovarian cancer contributed the remaining 28%. On average, 10.9 lesions were treated in a single session. Sixty-four percent of patients received prior whole-brain radiation therapy. The median survival was 6.5 months. One-year overall survival was 42% versus 14% when comparing breast cancer and other histological types, respectively (p = 0.074). Age, extracranial metastases, number of brain metastases, and previous CNS radiation therapy were not significant prognostic factors. Although the median time to local failure was not reached, the median time to regional failure was 3 months. Female sex was associated with longer time to regional failure (p = 0.004), as was breast cancer histological type (p = 0.089). No patient experienced symptomatic necrosis. CONCLUSIONS: Patients with ≥ 10 brain metastases who received prior CNS radiation can safely undergo repeat treatment with GK-SRS. With median survival exceeding 6 months, aggressive local treatment remains an option; however, rapid CNS failure is to be expected. Although numbers are limited, patients with breast cancer represent one group of individuals who would benefit most, with prolonged survival and extended time to CNS recurrence.


Assuntos
Neoplasias Encefálicas/mortalidade , Encéfalo/cirurgia , Radiocirurgia/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/patologia , Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/cirurgia , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Prognóstico , Radiocirurgia/métodos , Taxa de Sobrevida , Resultado do Tratamento
13.
Cancer ; 118(16): 3893-8, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22864932

RESUMO

BACKGROUND: To assess the potential mechanisms that may underlie increased local failure in triple negative (TN) breast cancers, an analysis was performed of the risk of residual carcinoma after lumpectomy with correlation to pathologic factors, including molecular phenotype. METHODS: A review of pathologic specimens was performed for women with invasive breast cancer treated with lumpectomy followed by reexcision. Data were collected on age; tumor size, grade, and nodal stage; estrogen receptor, progesterone receptor, and human endothelial growth factor receptor 2 (Her2); extensive intraductal component; lymphovascular invasion; margins; and reexcision findings. Univariate and multivariate logistic regression analyses were performed to evaluate for associations between pathologic features of the lumpectomy specimen and reexcision findings. Molecular phenotypes were defined by conventionally used immunohistochemical pattern. RESULTS: Data were collected on 369 patients with breast cancer. The median age was 57 years, median tumor size was 1.5 cm, 36% had positive margins, 32% had positive lymph nodes, 73.5% had the luminal A subtype, 9.5% had the luminal B subtype, 4.5% were Her2-enriched, and 12.5% were TN. Overall, 32% of patients had invasive cancer in their reexcision specimens, and 51% of those with the TN subtype had residual invasive disease on reexcision compared with 30% to 31% for other subtypes. On univariate analysis, age, tumor size, margin status, lymphovascular invasion, nodal status, and TN subtype were associated with elevated risk of residual invasive cancer. On multivariate analysis using a forward stepwise model, TN subtype maintained significance, with an odds ratio of 3.28 (P = .002). CONCLUSION: TN subtype has a statistically significant association with an increased risk of residual tumor. This suggests the putative increase in the risk of local failure in TN patients may be related to increased residual tumor burden.


Assuntos
Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Neoplasia Residual/patologia , Adulto , Aminopirina , Neoplasias da Mama/metabolismo , Combinação de Medicamentos , Feminino , Humanos , Metástase Linfática , Mastectomia Segmentar , Pessoa de Meia-Idade , Invasividade Neoplásica , Recidiva Local de Neoplasia/patologia , Fenilbutazona , Risco
14.
Am J Clin Oncol ; 35(6): 587-92, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21926900

RESUMO

PURPOSE: : The purpose of the study was to identify patient characteristics that predict for increased cardiac exposure through dosimetric analysis of the anatomy of a cohort of women treated with left-sided tangential breast radiation. Statistical analyses estimations for the appropriate sample sizes required for detection of significant differences in cardiac mortality at 15 years were conducted, assuming a threshold V25 for radiation-induced coronary artery disease (CAD) beyond which women are at risk for radiation-induced coronary artery disease. METHODS AND MATERIALS: : Detailed heart dosimetry was recorded. Clinical factors (age, history of CAD, diabetes, receipt of cardiotoxic agents, weight/body mass index) and anatomic factors (heart volume, breast volume, cardiac contact distance) were recorded for each patient. RESULTS: : The average heart V25 was 3.57%. The median percentage of the heart included in the tangential beam was 4.02%. There were no clinical or anatomic factors that predict suboptimal heart anatomy (ie, V25 of ≥6%) on multivariate analysis. The sample size calculations using thresholds for induction of CAD of V25 ≥1%, 6%, and 10% yielded sample sizes of 1314, 9504, and 61,342, respectively; considering node-positive breast cancer mortality and 15% loss to follow-up, these change to 2237, 16,166, and 104,334, respectively. CONCLUSIONS: : Current studies with modern radiotherapy techniques would be underpowered to detect a difference in cardiac mortality where only some women are at risk. The heart, chest wall, and breast have a complex relationship to tangential breast radiation, and their interplay prevented this anatomic metric's success.


Assuntos
Neoplasias da Mama/radioterapia , Mama/anatomia & histologia , Carcinoma/radioterapia , Doença da Artéria Coronariana/mortalidade , Coração/anatomia & histologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Doença da Artéria Coronariana/etiologia , Feminino , Coração/efeitos da radiação , Humanos , Pessoa de Meia-Idade , Análise Multivariada , Tamanho do Órgão , Lesões por Radiação/etiologia , Dosagem Radioterapêutica
15.
Med Phys ; 38(3): 1519-25, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21520863

RESUMO

PURPOSE: AccuBoost is a noninvasive image-guided technique for the delivery of partial breast irradiation to the tumor bed and currently serves as an alternate to conventional electron beam boost. To irradiate the target volume while providing dose sparing to the skin, the round applicator design was augmented through the addition of an internally truncated conical shield and the reduction of the source to skin distance. METHODS: Brachytherapy dose distributions for two types of conical applicators were simulated and estimated using Monte Carlo (MC) methods for radiation transport and a conventional treatment planning system (TPS). MC-derived and TPS-generated dose volume histograms (DVHs) and dose distribution data were compared for both the conical and round applicators for benchmarking purposes. RESULTS: Agreement using the gamma-index test was > or = 99.95% for distance to agreement and dose accuracy criteria of 2 mm and 2%, respectively. After observing good agreement, TPS DVHs and dose distributions for the conical and round applicators were obtained and compared. Brachytherapy dose distributions generated using Pinnacle for ten CT data sets showed that the parallel-opposed beams of the conical applicators provided similar PTV coverage to the round applicators and reduced the maximum dose to skin, chest wall, and lung by up to 27%, 42%, and 43%, respectively. CONCLUSIONS: Brachytherapy dose distributions for the conical applicators have been generated using MC methods and entered into the Pinnacle TPS via the Tufts technique. Treatment planning metrics for the conical AccuBoost applicators were significantly improved in comparison to those for conventional electron beam breast boost.


Assuntos
Braquiterapia/instrumentação , Neoplasias da Mama/radioterapia , Órgãos em Risco/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Pele/efeitos da radiação , Software , Benchmarking , Método de Monte Carlo , Dosagem Radioterapêutica
16.
Front Oncol ; 1: 12, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22649753

RESUMO

The identification of distinct molecular subtypes of breast cancer has advanced the understanding and treatment of breast cancer by providing insight into prognosis, patterns of recurrence, and effectiveness of therapy. The prognostic significance of molecular phenotype with regard to distant recurrences and overall survival are well established in the literature and has been readily incorporated into systemic therapy management decisions. However, despite the accumulating data suggesting similar prognostic significance for locoregional recurrence, integration of molecular phenotype into local management decision making has lagged. Although there are some conflicting reports, collectively the literature supports a low risk of local recurrence (LR) in the hormone receptor (HR) positive luminal subtypes compared to HR negative subtypes [triple negative (TN) and HER2-enriched]. The development of targeted therapies, such as trastuzumab for the treatment of HER2-enriched subtype, has been shown to mitigate the increased risk of LR. Unfortunately, no such remedy exists to address the increased risk of LR for patients with TN tumors, making it a clinical challenge for radiation oncologists. In this review we discuss the correlation between molecular subtype and LR following either breast conservation therapy or mastectomy. We also explore the possible mechanisms for increased LR in TN breast cancer and radiotherapeutic implications for this population, such as the safety of breast conservation, consideration of dose escalation, and the appropriateness of accelerated partial breast irradiation.

17.
Int J Radiat Oncol Biol Phys ; 80(2): 410-6, 2011 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20646854

RESUMO

PURPOSE: To perform dose modeling of a noninvasive image-guided breast brachytherapy (NIIGBB) for comparison to electrons and 3DCRT. METHODS AND MATERIALS: The novel technology used in this study is a mammography-based, noninvasive breast brachytherapy system whereby the treatment applicators are centered on the planning target volume (PTV) to direct (192)Ir emissions along orthogonal axes. To date, three-dimensional dose modeling of NIIGBB has not been possible because of the limitations of conventional treatment planning systems (TPS) to model variable tissue deformation associated with breast compression. In this study, the TPS was adapted such that the NIIGBB dose distributions were modeled as a virtual point source. This dose calculation technique was applied to CT data from 8 patients imaged with the breast compressed between parallel plates in the cranial-caudal and medial-lateral axes. A dose-volume comparison was performed to simulated electron boost and 3DCRT APBI. RESULTS: The NIIGBB PTV was significantly reduced as compared with both electrons and 3DCRT. Electron boost plans had a lower D(min) than the NIIGBB technique but higher V(100), D(90), and D(50). With regard to PTV coverage for APBI, the only significant differences were minimally higher D(90), D(100), V(80), and V(90), with 3DCRT and D(max) with NIIGBB. The NIIGBB technique, as compared with electrons and 3D-CRT, achieved a lower maximum dose to skin (60% and 10%, respectively) and chest wall/lung (70-90%). CONCLUSIONS: NIIGBB achieves a PTV that is smaller than electron beam and 3DCRT techniques. This results in significant normal tissue sparing while maintaining dosimetric benchmarks to the target tissue.


Assuntos
Braquiterapia/métodos , Neoplasias da Mama/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Algoritmos , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Elétrons/uso terapêutico , Feminino , Humanos , Radioisótopos de Irídio , Mamografia/instrumentação , Mamografia/métodos , Seleção de Pacientes , Dosagem Radioterapêutica , Carga Tumoral
18.
Brachytherapy ; 7(4): 327-35, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18782684

RESUMO

PURPOSE: Modern dosimetry data are not available for Collaborative Ocular Melanoma Study-based eye plaques. This report aims to provide these data for eye plaques ranging from 10 to 22 mm, and for three different low-energy, photon-emitting radionuclides. METHODS AND MATERIALS: Recent publications on brachytherapy dosimetry parameters for 103Pd, 125I, and 131Cs were evaluated for use as eye plaque reference data. These data were entered into the Pinnacle treatment planning system for 3D calculations of brachytherapy dose distributions along the central axis for depths ranging from -1 to 10 mm based on the origin positioned at the inner sclera. In accordance with the original Collaborative Ocular Melanoma Study protocol and in the absence of radionuclide-specific heterogeneity factors, inhomogeneity corrections were not applied. RESULTS: As expected due to the mean photon energies, 103Pd, 125I, and 131Cs provided increasingly penetrating dose distributions. Dose distribution tables were prepared for fully loaded plaques and for plaques with the central source(s) removed. Over the entire range of central axis depths, and for all plaque sizes and loadings, 131Cs produced minimal outer scleral doses. Similarly, 103Pd generally produced more favorable dose distributions than 125I for depths less than 4mm. CONCLUSIONS: A modern analysis of eye plaque dosimetry evaluated dose as a function of lesion height and applicator size, and showed dependence on radionuclide selection and implant duration. For a fixed dose at the prescription point, we observed higher scleral dose corresponded with lower photon energy for a variety of plaque sizes and lesion heights.


Assuntos
Braquiterapia/instrumentação , Melanoma/radioterapia , Radioisótopos/administração & dosagem , Esclera/efeitos da radiação , Neoplasias Uveais/radioterapia , Braquiterapia/métodos , Relação Dose-Resposta à Radiação , Humanos , Método de Monte Carlo
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