PO-1048: HDR Brachytherapy Combined to EBRT for Prostate Cancer: Analysis of Toxicities and PSA Bounce of a Phase II Trial

Purpose/Objective: To assess acute and late toxicities and report the frequency and timing of the PSA bounce in intermediate-risk prostate cancer patients treated with brachytherapy and hypofractionated external beam radiotherapy (EBRT) combined with short course androgen deprivation therapy (ADT).Materials and Methods: Between August 2003 and September 2007, 51 patients with intermediate-risk prostate cancer were enrolled in a dose escalation phase II protocol (BRP-1 trial).The treatment regimen applied was as followed: patients received six months of ADT (three months neoadjuvantly and three months concurrently) and underwent high-dose-rate (HDR) Ir 192 prostate brachytherapy, for a prescribed dose of 19.5Gy (three fractions of 6.5Gy each); followed one week later, by hypofractionated EBRT at a dose of 50Gy in 20 fractions.Patients were assessed one month post-treatment, every three to six months for the first five years and annually thereafter.APS, testosterone and complete blood count were taken on each visit.Gastrointestinal (GI), genitourinary (GU) and sexual toxicities were assessed according to the RTOG toxicity scoring criteria.Patients also completed the Expanded Prostate Cancer Index Composite (EPIC) questionnaires for quality of life every 6 months.Results: Median age was 68.5 years (range 51-83 years).At diagnosis, 31.8% of patients had grade 2 or higher for GU symptoms according to the RTOG scoring criteria, no one had grade 2 GI symptoms and 50% had grade 2 or higher erectile dysfunction.Median follow-up was 80 months (range 4.9-132 months).Rates of grade 2 and higher GU toxicity at 1, 12 and 60 months were 33.8%, 12.8% and 23.5%, respectively.No grade 2 or higher GI toxicities were reported at 1 and 12 months and a rate of 5.9% was observed at 60 months.Grade 2 and 3 erectile dysfunction at 1, 12 and 60 months was reported in 2.1%, 19.2% and 16.1% and 91.7%, 57.2% and 71% of patients respectively.No grade 4 toxicity was reported.PSA bounce was observed in 33.3% of patients at a median of 12 months (range 3-42 months) and the median time to PSA normalization was 18 months (range 3-24 months).Conclusions: Acute and late GU and GI toxicities were acceptable for patients with intermediate-risk prostate cancer treated with HDR brachytherapy and hypofractionated EBRT combined to short course ADT.Rates of erectile dysfunction were probably affected by the use of a short course of ADT.PSA bounces are common, and occur up to 42 months in our cohort.