To do so, the authors used the North American Association of Central Cancer Registries to determine age-adjusted incidences of metastatic prostate cancer at diagnosis per 100,000 men between 2002 – 2016 for each state. The authors then used the Behavioral Risk Factor Surveillance System, which collects this information for men at least 40 years of age every 2 years from 2002 onward, to determine state-level survey-weighted estimates of PSA screening. PSA screening and metastasis data were collated as a multi-panel time series and then analyzed using a random-effects linear regression model with random effects at the state level.
Dr. Sharma and colleagues identified significant variation between states in the percent of men age >40 years who reported ever receiving PSA screening (range 40.1% to 70.3%) and in the age-adjusted incidence of metastatic prostate cancer at diagnosis (range 3.3 to 14.3 per 100,000). Between 2008 and 2016, across all states, the mean percentage of men undergoing PSA screening decreased (61.8% to 50.5%) whereas the mean incidence of metastatic prostate cancer at diagnosis increased (6.4 to 9.0 per 100,000; Bonferroni adjusted p < 0.001 for both).
Using a random-effects linear regression model, the authors found that longitudinal reductions in PSA screening across states were associated with increased rates of de novo metastatic prostate cancer (regression coefficient per 100,000 men: 14.9, 95% confidence interval [CI] 12.3 – 17.5, p < 0.001), suggesting that states with larger declines in PSA screening had larger increases in the incidence of metastatic prostate cancer at diagnosis.
Just over a quarter (27%) of longitudinal variation in rates of metastatic prostate cancer at diagnosis within states could be explained by variation in PSA screening.
The authors, therefore, conclude that reductions in PSA screening are likely to explain some of the observed increase in metastatic prostate cancer.
Presented by: Vidit Sharma, MD, Resident of Urology, Mayo Clinic, Rochester, Minnesota
Written by: Christopher J.D. Wallis, MD, PhD, Urologic Oncology Fellow, Vanderbilt University Medical Center, Nashville, Tennessee, Twitter: @WallisCJD during the 2021 ASCO Genitourinary Cancers Symposium (ASCO GU), February 11th to 13th, 2021