Prognostic implications of an undetectable ultrasensitive prostate-specific antigen level after radical prostatectomy.

BACKGROUND: The prognostic meaning of an undetectable ultrasensitive prostate-specific antigen (USPSA) level after prostatectomy remains unclear.
OBJECTIVE: To determine whether an undetectable USPSA level obtained after surgery is a predictor of biochemical recurrence (BCR)-free survival. DESIGN, SETTING, AND PARTICIPANTS: From the Urologic Oncology Database at the University of California San Francisco, 525 men were identified who had a USPSA measurement 1-3 mo postoperatively with at least 2 yr of follow-up. All preoperative and pathologic criteria were recorded. MEASUREMENTS: Patients were stratified based on their initial USPSA level. We defined an undetectable USPSA level at ≤0.05 ng/ml. Recurrence was defined as two consecutive prostate-specific antigen (PSA) levels ≥0.2 ng/ml or secondary treatment. RESULTS AND LIMITATIONS: We found that 456 patients (87%) had undetectable USPSA and 69 patients (13%) had detectable USPSA immediately postprostatectomy. A 5-yr recurrence-free rate of 86% was found in the undetectable USPSA group compared with 67% in the detectable USPSA group (p<0.01). For patients with pT3 disease, men with an undetectable USPSA had a 5-yr BCR-free survival rate of 78% compared with 40% for men with a detectable USPSA (p<0.01). A multivariable analysis confirmed that patients with an undetectable USPSA were 67% less likely to recur (hazard ratio: 0.33; 95% confidence interval: 0.20-0.55). As the detection level of PSA is lowered, the false-positive rate of BCR necessarily increases. A limitation of the study is its retrospective nature.
CONCLUSIONS: An undetectable USPSA after radical prostatectomy is a prognostic indicator of BCR-free survival at 5 yr and may aid in predicting outcome in higher risk patients.