Salvage radiotherapy in prostate cancer patients with biochemical relapse after radical prostatectomy : Prolongation of prostate-specific antigen doubling time in patients with subsequent biochemical progression.

Abstract

In patients with prostate cancer (PCa) and biochemical progression (BP) after radical prostatectomy (RP), salvage radiotherapy (sRT) improves prostate cancer-specific survival (PCSS), but this evidence is based only on retrospective data. In addition to our previous study of 151patients with PCa and BP after RP, we performed univariate analyses of prostate-specific antigen (PSA) kinetics during sRT. In 11patients with BP or initiation of hormonal treatment (HT) within 180days after sRT, risk factors were assessed using Mann-Whitney Utests. PSA doubling times (PSADT) before and after sRT in 82patients with BP after sRT were compared by aWilcoxon test. After amedian follow-up of 82months, analysis of PSA kinetics during sRT did not show astatistically significant impact on asubsequent BP, PCSS, or overall survival at an administered dose of 30 or 45 Gy. The subgroup analysis of patients with early BP or early HT revealed higher Gleason scores (p= 0.008) and preoperative PSA values (p= 0.005), shorter PSADT prior to sRT (p< 0.0005), and longer time intervals from RP until the start of sRT (p= 0.005) compared to all other patients. In patients with subsequent BP, PSADTs were significantly prolonged after sRT (median PSADT 4.5months before and 9.9months after sRT, p< 0.0005). PSA monitoring during sRT did not predict the therapeutic success. Subgroup analysis suggests alower probability of benefit for patients with the abovenamed risk factors . However, the prolonged PSADT after sRT reflects abenefit of sRT for the vast majority of patients.