Clinical outcomes following biochemical recurrence among patients with Gleason score 9-10 prostate adenocarcinoma.

Abstract

Listen

Translate article

102 Background: Patients with Gleason score (GS) 9-10 prostate cancer (PCa) have a high risk of early biochemical recurrence (BCR). Salvage therapy options differ depending on the upfront management strategy. Patients who received upfront surgery (RP) may be curable with salvage external beam radiation therapy (EBRT). However those who underwent EBRT or EBRT with a brachytherapy boost (EBRT+BT) are less likely to receive local salvage therapy and are commonly treated with androgen deprivation therapy (ADT). In this study, we examine the risk of distant metastases (DM) and prostate-cancer specific mortality (PCSM) among patients with GS 9-10 PCa who had BCR following RP, EBRT, or EBRT+BT. Methods: 712 patients with GS 9-10 PCa treated between 2000-2013 at 12 institutions who had BCR were included (346 RP, 282 EBRT, 84 EBRT+BT). Time to DM and PCSM were compared between groups using Cox proportional hazards models with propensity score adjustment. Propensity scores were calculated using age, T-stage, PSA, and GS. Results: In patients who had a BCR, incidence rates of DM and PCSM after RP were 40% and 28%. Rates after EBRT were 60% and 46% and after EBRT+BT were 49% and 31%. Median times to DM and PCSM were 3.5 and 4.9 years after RP, 3.7 and 5.1 years after EBRT, and 3.3 and 6.8 years after EBRT+BT. The rates of local salvage RT and systemic salvage therapy among RP patients were 38% and 59%, respectively. Local and systemic salvage rates were 5% and 31% for EBRT patients and 5% and 28% for EBRT+BT patients. EBRT patients had a shorter time interval to DM compared with RP (HR 1.4, p = .02) and EBRT+BT (HR 1.9, p < .01). EBRT patients also had a shorter time interval to PCSM compared with RP (HR 1.5, p = .02). Conclusions: Among patients with GS 9-10 PCa who experience BCR after definitive management, those treated with EBRT have a shorter time interval to DM and PCSM compared with RP and EBRT+BT. While this analysis is confounded by the differential thresholds for diagnosing a BCR after different modalities, it does suggest that outcomes following BCR after EBRT+BT and RP are similar. It also suggests that extreme dose escalation delays the onset of DM and PCSM even after BCR, when compared with conventionally-dosed EBRT alone.