Clinical and genetic determinants of toxicity and quality-of-life (QOL) outcomes for SBRT in Asian prostate cancer.

95Background: There is limited data on clinical and patient-reported quality of life (PRO-QOL) outcomes after stereotactic body radiotherapy (SBRT) in Asian men with localised prostate cancer. Demographic differences with regard to PRO-QOL outcomes may be due to variation in germline genetics. We therefore conduct a single-institution prospective phase II trial of prostate SBRT in Asian men with intermediate-risk prostate cancers (IR-PCa). Additionally, we investigated association of dosimetric and genetic factors with outcomes. Methods: Patients with biopsy-proven NCCN-defined IR-PCa were recruited. SBRT was delivered at 36.25 Gy/5fr using a Linac-based RapidArc technique. Adverse events (AEs) were assessed with CTCAEv4.0 and IPSS; PRO-QOL assessed using the EPIC instrument at baseline, 1 and 2-year post-SBRT. Germline genetics were profiled by whole exome sequencing (30X). Results: 65 patients were recruited over the period of 2014-2016 (median follow-up = 30 mo). We observed 4 acute ≥G2 gastrointestina...