The possibility of hormone-mediated PSA derangement in prostate cancer treatment

This study was designed to suggest the possibility of hormone-related derangement in salvage radiotherapy (SRT) after radical prostatectomy in terms of prostate-specific antigen (PSA) control.
Among 160 consecutive prostate cancer patients who received radical prostatectomy, 34 with SRT between 2004 and 2012 were retrospectively reviewed. The numbers of patients with pathologic T3-T4 stage, Gleason score 8-10, and positive resection margin were 11 (32.4%), 10 (29.4%), and 17 (50.0%), respectively. Median SRT dose was 64.8 Gy (range, 52.9-70.0 Gy) with 1.8-2.3 Gy fractionations. Biochemical failure-free survival after SRT was counted and the median follow-up period was 32.5 months (range, 10-118 months).
After SRT, the median time for PSA to decrease to less than 0.2 ng/mL was four months (range, 0-25 months). The three-year survival rate was 60.3%. On univariate analysis, preferential hormone therapy (PHT) (p=0.022), higher PSA at SRT (p=0.005), and higher PSA after surgery (p=0.003) were related to a shorter biochemical survival period. On multivariate analysis, lower PSA at SRT (p=0.016), higher radiation dose (p=0.007), and non-PHT (p=0.046) suggested a consistent PSA control.
According to these results, low PSA values by hormonal intervention need to be reconsidered with a different way to look at the relationship between the PSA and hormone therapy. SRT should be considered for postoperative salvage treatment regardless of the hormone-related PSA values.