National trends in the recommendation of radiotherapy after prostatectomy for prostate cancer before and after the reporting of a survival benefit in March 2009

Abstract

Background: Three randomized trials demonstrated that postprostatectomy adjuvant radiotherapy improves biochemical disease-free survival for patients with adverse pathologic features, and 1 trial found adjuvant radiotherapy improves overall survival. We sought to determine whether postprostatectomy radiotherapy (PPRT) utilization changed after publication of the survival benefit in March 2009.

Patients and methods: The Surveillance, Epidemiology, and End Results database was used to identify men diagnosed with prostate cancer from 2004 to 2011 who met criteria for enrollment in the randomized trials (positive margins and/or pT3-4 disease at radical prostatectomy). Joinpoint regression identified inflection points in PPRT utilization. Logistic regression was used to evaluate factors associated with PPRT recommendation.

Results: Of 35,361 men, 5104 (14.4%) received a recommendation for PPRT. In joinpoint regression, 2009 was the inflection point in PPRT utilization. In multivariable analysis, PPRT recommendations were more likely after March 2009 than before 15.8% vs. 13.5%, adjusted odds ratio (AOR; 1.09; 95% confidence interval [CI], 1.02-1.16; P = .008), in men with pT3 (vs. pT2, AOR, 2.81; 95% CI, 2.53-3.11; P < .001), pT4 (vs. pT2 AOR, 4.62; 95% CI, 3.85-5.54; P < .001), or margin positive (AOR, 1.46; 95% CI, 1.34-1.58; P < .001) disease and in men who were younger (per year decrease, AOR, 1.02; 95% CI, 1.02-1.03; P < .001), married (AOR, 1.10; 95% CI, 1.02-1.19; P = .01), or lived in metropolitan areas (AOR, 1.30; 95% CI, 1.16-1.47; P < .001).

Conclusion: PPRT recommendations increased after the reporting of a survival benefit in March 2009, but absolute utilization rates remain low, suggesting that the oncologic community remains unconvinced that PPRT is needed for most patients with adverse features. Further work is needed to identify patients who might benefit most from PPRT.

Keywords: Adjuvant; Prostatectomy; Prostatic Neoplasm; Radiation Therapy; Randomized Control Trial.