Assessment of the Rate of Adherence to International Guidelines for Androgen Deprivation Therapy with External-beam Radiation Therapy: A Population-based Study

Background The National Comprehensive Cancer Network and the European Association of Urology guidelines recommend using radiation therapy (RT) with androgen deprivation therapy (ADT) to treat high-risk and locally advanced prostate cancer patients. Objective To evaluate the degree of adherence to these guidelines. Design, setting, and participants Between 2003 and 2009, in the Surveillance Epidemiology and End Results (SEER)–Medicare database, 14 180 patients were diagnosed with high-risk (T1–T2 with World Health Organization histologic grade 3) or locally advanced (T3–T4 with any histologic grade) prostatic adenocarcinoma. Intervention Administration of RT-ADT versus RT alone. Outcome measurements and statistical analysis We assessed the rate of adherence to guidelines with respect to use of RT-ADT in the overall population and after stratification according to stage–grade groupings (T1–T2 G3 vs T3–T4 any grade), age (66–69, 70–74, 75–79, ⠥80 yr), Charlson Comorbidity Index (CCI) (0, 1, ⠥2), and preexisting baseline cardiovascular (CV) disease. We depicted the rate of RT-ADT administration graphically over the study period. Multivariable logistic regression analyses were performed to assess the predictors of RT-ADT use. Results and limitations RT-ADT rates and guideline adherence were 58–75%, with the highest rate (75%) in 2003 and the lowest (58%) in 2009. When stratified according to stage–grade groupings, age, CCI, and preexisting baseline CV disease, similar results were obtained. In multivariable analyses, year of diagnosis (p < 0.001), patient age (p < 0.001), stage–grade groupings (p < 0.001), CCI (p = 0.036), race (p < 0.001), marital status (p < 0.001), population density (p < 0.001), and US regions (p < 0.001) were independent predictors of RT-ADT use. The limitations of our study include age >65 yr and exclusive Medicare coverage. Conclusions The rate of guideline adherence regarding the use of RT-ADT is suboptimal and decreases with time instead of increasing. Patient summary This population-based study provides evidence of low adherence to international urologic guidelines regarding the combination of radiation therapy (RT) with androgen deprivation therapy (ADT) for high-risk and locally advanced prostate cancer (PCa) patients. Despite the increasing number of randomized controlled trials over time that showed a survival benefit for patients with high-risk and locally advanced PCa treated with RT-ADT compared with RT alone, the rate of adherence to guidelines decreased with time.