Patients treated with radical prostatectomy with positive digital rectal examination findings in the intermediate-risk group are prone to PSA recurrence.

The present study aimed to evaluate the possibility of performing radical prostatectomy (RP) alone to achieve a radical cure for prostate cancer in the intermediate-risk group. Samples were collected from 638 Japanese patients who underwent antegrade RP between August 1998 and May 2013; subsequently, 157 patients were excluded. According to the D'Amico criteria, the low-, intermediate- and high-risk groups comprised 107, 222 and 152 patients, respectively. The 5-year prostate-specific antigen (PSA) failure-free survival rates in the low-, intermediate-, and high-risk groups were 96.5, 88.9 and 72.6%, respectively (P<0.001; degrees of freedom=2). In the intermediate-risk group, the difference in PSA failure-free survival between the 0<PSA≤10 and 10<PSA≤20 ng/ml, and the biopsy Gleason score 6 and 7 groups were not statistically significant, according to the log-rank test (P=0.2266 and P=0.1329, respectively). However, the difference in PSA failure-free survival between the clinical tumor stage (cT)1c and cT2a/b groups was statistically significant based on the log-rank test (P<0.0001). The results of the multivariate analysis revealed that, of the preoperative characteristics, only the cT was a significant predictor in patients with and without PSA failure (P<0.001). Therefore, patients classified into the intermediate-risk group with cT2a/b stage, according to positive digital rectal examination findings, and are not considered to be likely to achieve a complete cure with RP surgery alone. In summary, for patients meeting these criteria in the intermediate-risk group, RP surgery alone is likely to be insufficient, and other additional treatments may be considered subsequent to RP.