Influence of the breast prosthesis volume in dose distribution in radiotherapy planning

Introduction: The challenge of modern radiotherapy (RT) in breast cancer is to maintain its satisfactory oncological results, adapting to oncoplastic surgery and avoiding possible cosmetic damage. Considering that the breast prosthesis is not a target volume in RT planning, this study sought to analyze the effect of this volume on the coverage of the clinical target volume (CTV) of the breast. Methods: We performed a retrospective analysis of plans in 48 patients who submitted to RT in the first half of 2014. Two volumes were measured, such as breast CTV (breast tissue with the prosthesis) and real CTV (breast tissue excluding the prosthesis). The D95% values (dose that covers 95% of the volume) for each of them were verified and related to the volume of each one as well as the volume of breast prosthesis. Results: The analysis of the CTVs showed a significant difference between the mean volumes for the real CTV and breast CTV. While performing the CTV coverage, including the prosthesis, there is a perception that the dose covered 95% of the volume. Nevertheless, the analysis of the same plan after prosthesis volume exclusion revealed a difficulty in covering 95% of the breast tissue volume, indicating the interference of the prosthesis in therapy planning. Considering the dosimetric aspects, there were patients with real CTV values below the ideal dose of 47.5 Gy, after exclusion of implant volume. Conclusions: Our data reflected the volume of the prosthesis as an important variable that should be considered when planning adjuvant RT.

Radiotherapy for pain management of bone metastases

PURPOSE: This is the first Brazilian study intended to evaluate the response of pain relief with radiotherapy in three different fractionations and the clinical differences in managing pain in patients with painful bone metastases. METHODS: Prospective study of patients with painful bone metastases referred to the Radiotherapy Sector of the Hospital de Câncer de Barretos for pain-relieving radiotherapy between March and December 2010. It is known that radiotherapy seems to alter the activation of osteoclast-mediated bone resorption, relieving pain in cases of painful bone metastases. Patients were assessed in relation to the status of pain intensity before and after the initiation of radiotherapy. Either a single fraction of 8Gy, five fractions of 4Gy or ten fractions of 3Gy were given. A visual analog scale (VAS) was applied by doctors, nurses and nursing technicians to assess pain intensity at each session of radiotherapy, and follow-up at 8, 30 and 90 days from the end of treatment. RESULTS: We evaluated 92 consecutive patients, 48 male and 44 female, with a median age of 58 years. We found that 14% of patients referred from the Palliative Care or Clinical Oncology sectors need better pharmacological analgesia due to severe pain, compared with 40.5% of patients from the other sectors (p = 0.004). We also found that the onset of pain relief to patients receiving 10 fractions of 300cGy analgesia without changing the pre-radiotherapy analgesia occurred with significance after the fifth fraction. Improvement in pain experienced within 90 days of follow-up was found in eighty percent of patients, independent of fractionated radiotherapy, site of metastases and the clinical condition of the patient. ISCUSSION/CONCLUSION: The Palliative Care and Clinical Oncology sectors expressed greater concern in regards to analgesia for the patient with painful bone metastases...

Ativação da proteína TGFbetaI latente em pulmão irradiado in vivo / Latent TGFbeta1 activation in the lung irradiated in vivo

OBJETIVO: Investigar no pulmäo, por imunohistoquímica, a localizaçäo das proteínas TGFbeta1 latente e TGFbeta1 ativa, se ocorre ativaçäo radioinduzida da proteína TGFbeta1 latente e a distribuiçäo das fibras colágenas em diversos períodos de tempo após irradiaçäo. MÉTODOS: 32 camundongos isogênicos (C57BL) foram divididos em dois grupos: GI (näo irradiado) com 12 animais e GII (irradiado) com 20 animais. Os animais do GII receberam radiaçäo gama (telecobaltoterapia, 60Co, com rendimento de 0,97Gy/min, dose única de 7Gy em corpo inteiro). Os camundongos dos grupos I e II foram sacrificados por estiramento cervical nos períodos de 1, 14, 30 e 90 dias após irradiaçäo. RESULTADOS: Os pulmöes irradiados apresentaram: 1) congestäo vascular e espessamento dos septos alveolares aos 30 dias e mais intensamente aos 90 dias depois da irradiaçäo; 2) aumento significante da deposiçäo de colágeno em todos os períodos de tempo após irradiaçäo; 3) fraca ativaçäo da proteína TGFbeta1 latente em um dia e intensa aos 14 dias depois da irradiaçäo em brônquios e alvéolos. Nossos resultados sugerem que células dos brônquios e alvéolos podem participar do complexo mecanismo de fibrose pulmonar radioinduzida atuando como fontes da proteína TGFbeta1 ativa