Adjuvant radiotherapy after radical prostatectomy shows no ability to improve rates of overall and cancer-specific survival in a matched case-control study.

Abstract

To assess the effect of adjuvant radiotherapy (aRT) on the rate of cancer-specific and overall survival after radical prostatectomy (RP) in a group of patients with a long-term follow-up, as there is controversy about the benefit of aRT after RP for prostate cancer when endpoints beyond biochemical and local recurrence are considered. Within a study cohort of 752 patients treated with RP, 118 (15.7%) received aRT; these patients were matched with controls who did not receive aRT after RP. Exact matches were made for pT stage, RP Gleason sum, surgical margin status, age (+/-10 years), year of surgery (+/-10 years) and delivery of hormonal therapy. Kaplan-Meier and life-table analyses were used to assess overall and cancer-specific survival The median (range) follow-up was 11.4 (0.1-41) years. The 10- and 20-year overall survival after RP in those with no aRT were, respectively, 81.1% and 44.8%, vs 75.5% and 40.0% in the aRT group (P = 0.1). The corresponding probabilities for cause-specific survival were, respectively, 97.3% and 89.0% vs 86.3% and 69.3% (P < 0.001). There was no statistically significant difference in the overall and cause-specific survival between the groups after matching (hazard ratio 0.9, log rank P = 0.6; and 2.1, log rank P = 0.1, respectively). Our analysis showed that, in a matched case-control study, aRT has no effect on overall and cancer-specific survival. Further randomized long-term studies are necessary to confirm these results.