Comparison of outcomes of radical prostatectomy with and without adjuvant pelvic irradiation in patients with pathologic stage C (T3N0) adenocarcinoma of the prostate.

Abstract

Patients with localized adenocarcinoma of the prostate gland (CaP) are frequently (approximately 50%) found at radical prostatectomy to have extracapsular disease or positive surgical margins. The management of these patients is a subject of controversy because some question the impact of this manifestation of CaP on patient survival or disease-free survival. Between 1976 and 1991, 241 patients with pathologic stage C (T3N0) were treated in this medical center. Of these 241 patients, 201 (83%) received a planned postoperative pelvic irradiation consisting of 48 Gy given to the prostatic fossa, whereas 40 (17%) patients were treated with radical prostatectomy alone. The two study urologists selected these patients not to receive postoperative irradiation based on intraoperative findings and important prognostic factors. Comparison of treatment outcomes in these two treatment groups is a subject of this report. The 201 patients treated with surgery-radiotherapy (S+RT) combination had a higher pathologic stage, greater incidence of seminal vesicle involvement, p = 0.002, and higher mean and median preoperative prostate-specific antigen level, p < 0.0001, than the 40 surgery (S) alone patients. There was no significant difference in the incidence of higher Gleason's score by the treatment group, p = 0.14. In univariate analysis, there was no significant difference in survival, disease-free survival, and time to failure between the two treatment groups. In multivariate analysis after controlling for pathologic stage and Gleason's score, the 201 adjuvant radiotherapy patients were predicted to have recurrence at 68% (95% confidence interval 39%-118%) the rate of the 40 surgery-alone patients. Local recurrence with or without metastatic disease was found in 10% of surgery-alone patients as compared to 5% in those also receiving postoperative irradiation. Treatment tolerance was very good with minor radiotherapy complications only. There was no significant difference in the incidence of incontinence between the two treatment arms. In summary: (a) The use of moderate-dose postoperative radiotherapy was of low toxicity and it did not increase the incidence of incontinence. (b) Local recurrence was 5% in S+RT and 10% in S-alone patients. (c) In multivariate analysis, S+RT patients had 68% rate of recurrence of S-alone patients. (d) Adjuvant RT probably reduces the risk of recurrence in patients with poor prognostic factors. (e) These data need to be interpreted with caution because of the nonrandomized nature of the study.