42 Background: To evaluate the oncologic outcomes and potential impact of delayed radical treatment in the form of radiotherapy (RT), in men with localized prostate cancer progressing after active surveillance (AS). Methods: We identified patients on AS subsequently treated with state-of-the-art RT (either dose-escalated image-guided intensity modulated radiotherapy [IG-IMRT] or low-dose-rate brachytherapy [LDR-BT]). Based on the clinical characteristics at time of AS progression, we compared the oncologic outcomes to matched patients treated with upfront RT after diagnose. One to two matching patients per AS case were identified from existing RT databases based on: age (+/- 3 years), clinical prognostic factors (NCCN risk group; PSA +/- 2ng/mL; cT category; primary and secondary Gleason score; percentage of diagnostic cores involved dichotomized at < or > 50%), and treatment modality (IG-IMRT or LDR-BT). We aimed to determine whether patients on AS have potentially compromised outcomes. Results: We identified 215 patients (out of 1070 AS cohort) undergoing RT after a median of 26 months (IQR 16-52.5) on AS. Median follow-up post RT was 4.8 years (IQR 2.9-7.2). No patient died of prostate cancer. At 5-years, the biochemical relapse free-, metastases free- and overall-survival rate were respectively 98.6%, 99.1%, 98.6% in the AS cohort. Matched cohort comprised 400 patients treated with IG-IMRT (71%) or LDR-BT (29%). Adequate matching was confirmed. The median follow-up post RT was 8.2 years (IQR 4.7-10). At 5-years, biochemical relapse free-, metastases free- and overall-survival rates of 98.5%, 98.7%, 93.7% respectively, which were not statistically different compared to those patients treated upon AS progression. Conclusions: Curative-intent radiotherapy (i.e. dose-escalated IG-IMRT or LDR-BT) after a period of AS renders excellent oncologic outcomes at 5 years. Moreover, the delay of therapy after a period of AS does not appear to result in inferior oncologic outcomes compared to patients with similar risk characteristics undergoing upfront radical radiotherapy.
1013 Conformal radiotherapy versus short-course intensity modulated radiotherapy for localized prostate cancer with daily transabdominal ultrasound localization of the prostate gland: Dosimetry and acute toxicity
