Prognostic significance of undetectable ultrasensitive prostate-specific antigen nadir after radical prostatectomy.

Objectives: To investigate the prognostic significance of undetectable ultrasensitive prostate-specific antigen (PSA) nadir in patients who received radical prostatectomy (RP) for prostate cancer.

Methods: We reviewed records of 384 patients who received RP for prostate cancer and were followed for at least 2 years with ultrasensitive PSA testing. Undetectable ultrasensitive PSA level was defined as <0.001 ng/mL. Subjects were categorized according to PSA nadirs: <0.001 ng/mL (group 1), 0.001 ng/mL ≤ and < 0.02 ng/mL (group 2), 0.02 ng/mL ≤ and < 0.05 ng/mL (group 3), or ≥0.05 ng/mL (group 4). Multivariate analysis was performed to identify independent predictors of biochemical recurrence-free survival. A receiver operator characteristics (ROC) curve was used to assess performances of multivariate model in predicting biochemical recurrence.

Results: Overall, 206 (53.6%) patients showed undetectable ultrasensitive PSA nadir. Subjects of groups 1, 2, 3, and 4 demonstrated significant differences in biochemical recurrence-free survivals (log rank P <.001). In multivariate analysis, undetectable ultrasensitive PSA nadir (P <.001) was observed to be an independent predictor of biochemical recurrence-free survival along with preoperative PSA level (P = .030), pathologic stage (P = .014), and pathologic Gleason score (P = .042). Area under the ROC curve demonstrating predictive performances of the multivariate model, which included ultrasensitive PSA nadir, was significantly larger than that of the model without it (P <.001).

Conclusions: Our results demonstrated that undetectable ultrasensitive PSA nadir is a useful predictor of biochemical recurrence-free survival among contemporary patients who received RP for prostate cancer.