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.