National predictors and trends for androgen deprivation therapy use in low-risk prostate cancer.

50 Background: Androgen deprivation therapy (ADT) is not recommended for low-risk prostate cancer due to its known harms and lack of benefits. We evaluated the incidence and predictors of ADT use in men with low-risk prostate cancer. Methods: We identified 197,980 patients in the National Cancer Database (NCDB) with low-risk prostate cancer (Gleason 3+3 = 6, PSA < 10ng/mL, and cT1-T2a) diagnosed from 2004 to 2012 with complete demographic and treatment information. We determined the incidence of ADT use and utilized multiple logistic regression to evaluate predictors of ADT use. Results: ADT use in low-risk prostate cancer patients declined steadily from 2004 to 2012 (17.6% vs. 3.5%). 80.6% of these patients underwent radiation, and 10.0% received ADT as primary therapy. Among 82,354 low-risk disease patients treated with radiation, demographic and treatment factors associated with increased likelihood of ADT use include older age (adjusted odds ratio [AOR] 1.04 per year, p < 0.001); Hispanic vs. non-Hispanic white ethnicity (18.9% vs. 17.8%, AOR 1.26, p < 0.001); having Medicare at age < 65 (15.3%, AOR 1.14, p = 0.008) or Medicare at age ≥ 65 (21.5%, AOR 1.11, p < 0.001) vs. private insurance (13.9%); having bottom quartile vs. top quartile income (19.4% vs. 16.3%, AOR 1.26, p < 0.001); being treated in a community cancer program (22.0%, AOR 1.60, p < 0.001) or a comprehensive community cancer program (18.7%, AOR 1.38, p < 0.001) vs. an academic/research cancer program (13.9%); and receiving brachytherapy vs. external beam radiation therapy (19.3% vs. 15.5%, AOR 1.32, p < 0.001). Increasing distance from the treatment facility was associated with decreased likelihood of receiving ADT (AOR 0.97 for every 100 miles, p = 0.001). Conclusions: Among men with low-risk prostate cancer, increasing age, Hispanic ethnicity, Medicare insurance, lower income level, treatment in a non-academic/research cancer program, and brachytherapy use were all associated with increased odds of receiving ADT. Given the lack of evidence supporting ADT use in low-risk disease and increasing evidence of its many side-effects, it is critical to understand why low-risk prostate cancer patients are still receiving ADT so that this practice may be reduced.