Usefulness of postoperative nadir prostate-specific antigen value by ultrasensitive assay as a predictor of prostate-specific antigen relapse for pathological T3 or positive surgical margins after radical prostatectomy for prostate cancer

Abstract

Our aim was to identify prognostic factors and examine the usefulness of postoperative nadir prostate-specific antigen (PSA) value obtained by ultrasensitive assay for prediction of PSA relapse in prostate cancer patients with pathological T3 (pT3) or positive surgical margins. We analyzed 102 patients who were pathological T2 with positive surgical margins or pT3 without pathological lymph node metastasis or neoadjuvant hormonal therapy. Patients were classified into three groups according to postoperative nadir PSA value: <0.01 ng/ml, ≥0.01 ng/ml but <0.02 ng/ml, and ≥0.02 but <0.10 ng/ml. PSA relapse-free rate was compared according to postoperative nadir PSA. Univariate and multivariate analyses with the Cox proportional hazards regression model identified prognostic factors for PSA relapse. Of the 102 patients, 22 (21.6%) developed PSA relapse within a median follow-up time of 31.3 months. PSA relapse-free rate at 30 months was 81.2%. Univariate and multivariate analyses revealed that postoperative nadir PSA was the only statistically significant risk factor: postoperative nadir PSA ≥0.01 ng/ml but <0.02 ng/ml (P = 0.009, HR: 4.502, 95% CI: 1.457-13.916); ≥0.02 ng/ml but <0.10 ng/ml (P < 0.001, HR: 15.126, 95% CI: 4.738-48.292). PSA relapse-free rates at 30 months in patients with postoperative nadir PSA <0.01 ng/ml, ≥0.01 ng/ml but <0.02 ng/ml, and ≥0.02 ng/ml but <0.10 ng/ml were 91.9, 57.1, and 20.0%, respectively. Postoperative nadir PSA value obtained by ultrasensitive assay was useful as a predictor of PSA relapse among patients with adverse pathological features. Patients with postoperative nadir PSA of <0.01 ng/ml may have low risk of PSA relapse.