Marieke van Son

106 CHAPTER 6 ABSTRACT Purpose For patients with a localized prostate cancer recurrence after radiotherapy, focal salvage treatment offers a less toxic alternative to whole-gland treatments, with the potential of preserving health-related quality of life (HR-QoL). With a focus on the patient’s per- spective of treatment, this study aims to describe HR-QoL after ultrafocal salvage high- dose-rate brachytherapy (HDR-BT), and to explore predictive factors affecting HR-QoL. Material and Methods We included 100 patients treated with ultrafocal salvage HDR-BT. Prostate cancer-re- lated HR-QoL was assessed by the EORTC QLQ-PR25 questionnaire. Domains were urinary symptoms, bowel symptoms and sexual activity/functioning. For each domain, a mixed effects model was made to estimate HR-QoL trends over time. For domains showing clinically relevant change (≥10 points difference), the mixed effects model was used to explore potential predictors (age, baseline HR-QoL score, T-stage, tumor location, CTV size, dose to organs at risk and history of ADT). Results Median follow-up was 20 months (IQR 13-30). Mean questionnaire response rate was 86% (range 72-100%). Median baseline scores were 12 (urinary), 0 (bowel) and 67/50 (sexual activity/functioning). Urinary symptoms and sexual functioning showed clini- cally relevant deterioration over time (maximum difference of 11 and 12 points, respec- tively). Worse baseline score and higher administered dose to the urethra (≥16 Gy) were predictive of increased urinary symptoms (p<0.01 and p=0.03). Better baseline score was predictive of better sexual functioning (p<0.01). Conclusion Ultrafocal salvage HDR-BT has negligible impact on bowel symptoms but does affect urinary symptoms and sexual functioning. Lower impact is predicted for patients with favorable urinary and sexual function at baseline. Urethral dose constraints should be closely monitored.