Prediction of Biochemical Recurrence Following Radiotherapy among Patients with Persistent PSA after Radical Prostatectomy: A Single-Center Experience

Abstract

Radiotherapy (RT) is applied in prostate cancer patients with a biochemical recurrence (BcR) after radical prostatectomy (RP). However, for the patients with persistent PSA but not undergoing the process of BcR, it remains unknown whether the application of RT can exempt them from the upcoming BcR. In this study, we identified 104 patients treated with RP who had persistent PSA level >0.1 but ≤0.2 ng/mL at 6–8 weeks after RP, of which 52 were treated with postoperative RT. Overall, 51 patients experienced BcR, among which 20 patients were treated with postoperative RT. The 5-year BCR-free survival rate of patients treated with or without postoperative RT was 96.2 and 50.0% respectively. Subgroup analysis showed that statistical differences in BcR-free survival were observed regarding to applying RT on patients with Gleason score ≤7 (p = 0.0365), with pathological tumor stage T2 or T3 (p = 0.0210 and p = 0.0073, respectively), without or with lymph node invasion (p = 0.0118 and p = 0.0303, respectively), with positive surgical margins (p < 0.0001), and with Pre-RT PSA ≤0.5 ng/mL (p < 0.0001). In multivariate analyses, PSA after surgery, Gleason score, pathological tumor stage, immediate androgen deprivation therapy after RP, and postoperative RT were significant predictors of BcR for patients with persistently elevated PSA (all p < 0.05). Finally, a coefficient-based nomogram was constructed with an excellent C-index for 5-year BCR prediction (0.76, 95% CI 0.73–0.79). These findings suggested that postoperative RT affords excellent control in BcR for patients with persistent PSA after surgery.