Recommendations for post-prostatectomy radiation therapy in the United States before and after the presentation of randomized trials

Abstract

Purpose: The EORTC 22911 and the SWOG 8794 studies, presented in 2004 and 2005, showed that adjuvant radiation therapy after prostatectomy improved biochemical disease-free survival in men with adverse pathological features. In this study we evaluated the use of post-prostatectomy radiation therapy following the presentation of these results, and the impact of margin involvement, pathological tumor stage, Gleason score and sociodemographic factors on post-prostatectomy radiation therapy recommendations.

Materials and methods: The SEER cancer registry was used to identify 21,917 men who underwent radical prostatectomy for N0M0 prostate cancer with adverse pathological features (pT3 or margin positive pT2 disease) from 2000 through 2007.

Results: After adjusting for age, diagnosis year, race, SEER region and county education level in a multivariable regression model, decreasing age, margin involvement and Gleason 8 to 10 cancer were associated with receiving post-prostatectomy radiation therapy (all p < 0.001). Men with pT3a (AOR 2.95, CI 2.64-3.29) and pT3b disease (AOR 6.77, CI 5.75-7.97) were more likely to receive post-prostatectomy radiation therapy than those with pT2 disease. The use of post-prostatectomy radiation therapy did not increase after the presentation of study results (p = 0.166).

Conclusions: While men with involved margins and more aggressive pathological disease features were more likely to receive post-prostatectomy radiation therapy, recommendations for post-prostatectomy radiation did not increase after the initial reports from the randomized trials, perhaps because these studies initially reported improved biochemical disease-free survival but not overall survival. Whether the recent report of a survival benefit from adjuvant radiation therapy in the SWOG trial will impact patterns of care requires further followup.