Abstract

  We compared robot-assisted radical prostatectomy (RARP) and open radical prostatectomy (ORP) for prostate cancer in terms of the rate of positive surgical margins. Among prostate cancer patients who had ≤cT2-stage disease and ≤20 ng/ml PSA at diagnosis, the comparison included 178 patients who underwent RARP between December 2013 and August 2017 (RARP group) and 132 patients who underwent ORP between January 2011 and December 2012 (ORP group). Patients who received preoperative adjuvant chemotherapy were excluded. The rate of positive surgical margins in the RARP group was 16.9%, which was significantly lower than the 28.8% noted for the ORP group (p = 0.012). By disease staging, when the comparison was limited to pT2-stage patients, the positive surgical margin rate in the RARP group was significantly lower than that in the ORP group (10.9% versus 23.4% ; p = 0.011), while no significant difference was found between the two groups when only pT3-stage patients were included in the comparison (32.6% versus 42.1%). Among patients with lesions at the apex of the prostate, the positive surgical margin rate in the RARP group was 6.7%, which was significantly lower than 18.9% in the ORP group (p = 0.013). No significant differences between the two groups were noted among patients with lesions at other sites (lateral, anterior, posterior, and bladder neck). When the precise positions of positive surgical margins in the apex of the prostate were divided into the anterior, rectal, and lateral sides and compared separately, the result was significantly lower at rectal side of apex in the RARP group (1.1%) than the ORP group (10.4%) (p = 0.0014). These results suggested that the apical dissection under a good magnified visual field with less bleeding in RARP may contribute to decreasing the positive surgical margin rate at the apex.