Postoperative early ultrasensitive prostate-specific antigen identifies patients at risk for biochemical recurrence in margin positive prostate cancers: a single-center study

To identify predictors for biochemical recurrence among patients with positive surgical margins (RM1) after radical prostatectomy and to examine the effect of ultrasensitive prostate-specific antigen measured early after prostatectomy on biochemical recurrence.We identified 705 patients with prostate cancer who were treated with radical prostatectomy without preoperative hormonal therapy at our institution between 2000 and 2014. The patients with RM1 who had a postoperative prostate-specific antigen <0.2 ng/ml without lymph node metastasis were evaluated for biochemical recurrence-free survival. Survival rates were calculated using the Kaplan-Meier method. The Cox regression model was used for multivariate analysis. The prediction of biochemical recurrence was assessed using area under the curve of the receiver operating characteristic.Among the 705 patients, 190 (27%) had RM1. Biochemical recurrence was evaluated in 164 patients, excluding 26 patients who underwent adjuvant therapy with or without lymph node metastasis. With a median follow-up of 55 months, the biochemical recurrence-free survival rate of the entire RM1 cohort was 78% at 2 years and 64% at 4 years. The multivariate analysis revealed that postoperative early ultrasensitive prostate-specific antigen >0.02 ng/ml was the significant risk factor for biochemical recurrence (hazard ratio 13.10). Meanwhile, the patients with postoperative early ultrasensitive prostate-specific antigen <0.01 ng/ml had a significantly lower risk for biochemical recurrence (hazard ratio 0.12). Area under the curve for the postoperative early ultrasensitive prostate-specific antigen value to predict biochemical recurrence was 0.789.The ultrasensitive prostate-specific antigen value measured early after prostatectomy was the potent predictor of biochemical recurrence among the patients with RM1.