Intensity of observation with active surveillance or watchful waiting in men with prostate cancer in the United States

Background Population-based studies assessing various active surveillance (AS) protocols for prostate cancer, to date, have inferred AS participation by the lack of definitive treatment and use of post-diagnostic testing. This is problematic as evidence suggests that most men do not adhere to AS protocols. We sought to develop a novel method of identifying men on AS or watchful waiting (WW) independent of post-diagnostic testing and aimed to identify possible predictors of follow-up intensity in men on AS/WW. Methods A predictive model was developed using SEER watchful waiting data to identify men >= 66 years on AS between 2010-2015, irrespective of post-diagnostic testing, and applied to SEER-Medicare database. AS intensity among different variables including age, prostate-specific antigen (PSA) level, number of total and positive biopsy cores, Charlson comorbidity index, race (Black vs. non-Black), US census region, and county poverty, income, and education levels were compared using multivariable regression analyses for PSA testing, surveillance biopsy, and magnetic resonance imaging (MRI). Results A total of 2238 men were identified as being on AS. Of which, 81%, 33%, and 10% had a PSA test, surveillance biopsy, and MRI scan within 1-2 years, respectively. On multivariable analyses, Black men were less likely to have a PSA test (adjusted rate ratio [ARR] 0.60, 95% CI: 0.53-0.69), MRI scan (ARR 0.40, 95% CI: 0.24-0.68), and surveillance biopsy (ARR 0.71, 95% CI: 0.55-0.92) than non-Black men. Men within the highest income quintile were more likely to undergo PSA test (ARR 1.16, 95% CI: 1.05-1.27) and MRI scan (ARR 1.60, 95% CI 1.15-2.27) compared to men with the lowest income. Conclusions Black men and men with lower incomes on AS underwent less rigorous monitoring. Further study is needed to understand and ameliorate differences in AS rigor stemming from sociodemographic differences.