Radiation Therapy for Prostate Cancer Using HYpofractionation Directed by UltraSound (RAPHYDUS): A Brazilian Public Health Care System Study.

PURPOSE: This study evaluated the toxicity associated with a short course dose-escalated hypofractionated radiation therapy (HFRT) using image guided RT with or without androgen suppression therapy in patients with prostate cancer. METHODS AND MATERIALS: This single-center prospective observational study included 132 patients with prostate cancer from 2016 to 2020. Patients received HFRT using image guided RT (84%) with 3-dimensional (91%) or intensity modulated RT (9%). Total prescribed doses were 66 Gy (63%), 63 Gy (12%), and 60 Gy (24%) in 22, 21, or 20 daily fractions depending on organ-at-risk dose constraints. Acute toxicity was scored using Radiation Therapy Oncology Group criteria and the international prostate symptom index. The expanded prostate cancer index composite questionnaire was used to collect quality of life data (ranging from 0-100). RESULTS: The study population consisted of 111 patients who completed RT during a period of 3 years. The risk groups were as follows: low risk (12%), intermediate (32%), and high (56%). None of the patients had suspicious lymph nodes. Ninety percent received androgen suppression therapy. Maximum acute genitourinary and gastrointestinal toxicity peaked at grade 3 in 4 of 111 evaluated patients (4%) and at grade 2 in 7 of 111 evaluated patients (8%), respectively. The average international prostate symptom score increased from 4.8 at pretreatment to 14.0 during week 4 and normalized (5.7) 3 months after treatment completion. CONCLUSIONS: The current HFRT dose-escalation trial has demonstrated the feasibility of administering 66 Gy in 22 fractions with low acute gastrointestinal and genitourinary toxicities. Further follow-up will report late toxicities and outcomes.

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.