Prostate specific antigen nadir determined using ultra‐sensitive prostate specific antigen as a predictor of biochemical progression after radical prostatectomy in Japanese males

OBJECTIVES: We examined whether the prostate specific antigen (PSA) nadir is a good predictor of biochemical failure after radical prostatectomy. METHODS: We retrospectively reviewed clinico-pathological data in 257 patients who underwent radical prostatectomy. Twenty-nine patients of whom PSA nadir did not reach 0.1 ng/mL and three patients in whom second line therapy was started before biochemical failure were excluded, and 225 patients were subject to this study. We evaluated the changes in PSA value at very low (from less than 0.01-0.10 ng/mL) levels using an ultra-sensitive PSA assay after radical prostatectomy. Biochemical failure was defined as three consecutive elevations of PSA to above 0.1 ng/mL. RESULTS: Biochemical failure-free survival was attained by 89.9% of patients at 1 year, 83.0% at 2 years, and 81.0% at 5 years. PSA nadir more than 0.01 ng/mL was strongly associated with biochemical failure after radical prostatectomy (P < 0.0001). Mean time to reach PSA nadir was 3.1 months. Preoperative PSA > 20 ng/mL (P = 0.0013), clinical T stage = T2 (P = 0.0462), Gleason score 8-10 (P = 0.0243) were also independent predictors of biochemical progression. CONCLUSIONS: Prostate specific antigen nadir determined by ultra-sensitive PSA assay is an important parameter that is objective, reliable, and easily measured, and useful for predicting the subgroups of patients both most likely and unlikely to exhibit biochemical progression.