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

Abstract

Objective: 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).

Patients and methods: 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.

Results: 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.

Conclusion: 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.