Usefulness of ultrasensitive prostate-specific antigen assay for early detection of biochemical failure after radical prostatectomy

BACKGROUND: In order to assess whether the prostate-specific antigen (PSA) nadir obtained with an ultrasensitive PSA assay can be used as a prognostic indicator for patients undergoing radical prostatectomy, we investigated it retrospectively. METHODS: Between October 1997 and July 2003, 46 patients underwent radical prostatectomy for prostate cancer at our institution. None of them received preoperative treatment. Levels of PSA were measured with an ultrasensitive PSA assay every 1-3 months after prostatectomy. Biochemical recurrence was defined as a PSA level of 0.2 ng/mL or higher. RESULTS: There was a significant difference in PSA nadir between the biochemical recurrence group and the no recurrence group (P < 0.001). The receiver operating characteristics (ROC) curve gave an optimal cut-off value for PSA nadir of 0.01 ng/mL, demonstrating a significant difference in biochemical recurrence after radical prostatectomy. No patient with a PSA nadir level <0.01 ng/mL showed biochemical failure, while 15 out of 22 patients with PSA nadir levels >or=0.01 ng/mL showed biochemical failure. CONCLUSION: The PSA nadir level obtained using an ultrasensitive PSA assay is an excellent predictor of biochemical recurrence after radical prostatectomy. Early detection of recurrence offers the possibility of early salvage therapy.