Comparison of surgery alone with surgery and adjuvant radiotherapy for pT3N0 prostate cancer

To compare the outcome between patients with pT3N0 adenocarcinoma of the prostate treated with radical prostatectomy (RP) and those receiving RP followed by a planned course of postoperative radiation therapy (RT).

During a period of 22 years 622 patients with pT3N0 prostate cancer were treated in one medical centre by RP. Of these, 199 (32%) were treated with surgery alone while 423 (68%) received planned postoperative pelvic RT (median 48 Gy). Patients were selected for RT by having a higher incidence of adverse prognostic factors than those undergoing RP alone. These prognostic factors included pathological stage (P = 0.001) preoperative prostate specific antigen (PSA) level (P < 0.001) and Gleason score (P = 0.18). The patients' median age was 66 years; the median follow-up was 6.1 years for all patients, 7 years for RP + RT and 5 years for the RP-alone.

The 5- and 10-year actuarial survival was 92% and 73%, respectively, for RP + RT patients, and nearly identical for those in the RP-alone group (P = 0.73). The 5- and 10-year disease-free survival (DFS; PSA < 0.05 ng/mL) was 69% and 51%, respectively, for the former, and 71% and 60%, respectively, for the latter group. There was no significant difference in DFS between the treatment groups by pathological stage and Gleason score (P = 0.77). Likewise, there was no significant difference in mean and median time to relapse. A preoperative PSA level of < 10 vs 10-25 vs > 25 ng/mL did not influence overall survival but a PSA of > 25 ng/mL was predictive of DFS (P = 0.02). In a multivariate analysis the Gleason score was the most important predictor for overall survival and DFS (P < 0.001), while pathological stage was predictive of clinical recurrence and DFS (P < 0.001). After controlling for pathological stage and Gleason score, RP + RT patients were predicted to recur at 92% of the rate of RP-alone patients (P = 0.65). In all, 43 (10%) patients developed a clinical recurrence in the RP + RT group, including 30 (7%) patients with distant metastases alone, 13 (3%) with local recurrence, with an additional 88 (21%) who had PSA recurrence (PSA > 0.05 ng/mL). This compared with 13 (6.5%) patients with clinical recurrence, including seven (3.5%) with local recurrence and 23 (11.6%) with PSA > 0.05 ng/mL in the RP-alone group. Postoperative RT was well tolerated and did not add to the incidence of surgical complications.

We propose that postoperative RT, as described here, helped to reduce the incidence of local recurrence and improved DFS to equal that of a lower-risk group of patients treated with RP alone. A randomized comparison is needed to define the role of adjuvant RT in patients with pT3N0 disease.