Regional Variation in Active Surveillance for Low-Risk Prostate Cancer in the US.

Importance: Active surveillance (AS) is now recognized as the preferred management option for most low-risk prostate cancers to minimize risks of overtreatment. Despite increasing use of AS in the US, wide regional variability has been observed, and these regional variations in contemporary practice have not been well described. Objective: To explore variations between county and Surveillance, Epidemiology, and End Results (SEER) regions in AS in the US. Design, Setting, and Participants: A cohort study using the SEER Prostate with Watchful Waiting (WW) database linked to the County Area Health Resource File for detailed county-level demographics and physician distribution data was conducted from January 2010 to December 2015. Analysis was performed in October 2020. A total of 79 825 men with clinically localized, low-risk prostate cancer eligible for AS or WW were included. Exposures: Multiple patient-, county-, and SEER region-level factors, including age, year of diagnosis, county-level densities of urologists, radiation oncologists, primary care physicians, and SEER registry region. Main Outcomes and Measures: Use of AS or WW as the initial reported treatment strategy were noted. Hierarchical mixed-effect logistic regression models were used to evaluate clustered random regional variation on use of AS or WW. Temporal trends by year in proportions of initial treatment type, as well as county-level local variation, were also estimated. Results: Of 79 825 men (mean [SD] age, 62.8 [7.6] years, 11 292 [14.1%] non-Hispanic Black, 7506 [9.4%] Hispanic) with low-risk prostate cancer, the mean annualized percent increase in AS rates from 2010 to 2015 ranged from 6.3% in New Mexico to 81.0% in New Jersey. Differences across SEER regions accounted for 17% of the total variation in AS. Increasing age (51-60 years: odds ratio [OR], 1.33; 95% CI, 1.21-1.46; 61-70 years: OR, 1.86; 95% CI, 1.70-2.04; 71-80 years: OR, 2.26; 95% CI, 2.05-2.50) was associated with greater odds of AS. Hispanic ethnicity (OR, 0.79; 95% CI, 0.74-0.85), T category (OR, 0.79; 95% CI, 0.73-0.84), and Medicaid enrollment (OR, 0.73; 95% CI, 0.66-0.81) were associated with lower odds of AS. Black race, county-level socioeconomic factors (household income, educational level, and city type), and specialist densities were not associated with AS use. Conclusions and Relevance: In this US cohort study based on the SEER-WW database, although the use of AS increased, considerable practice variation appeared to be associated with geographic location, but use of AS was not associated with Black race, specialty professional density, or socioeconomic factors. This small area variation underlies the broader national trends in AS practice and may inform policies aimed at continuing to affect risk-appropriate care for men throughout the US.