ASPO Abstracts
Geographic Variation in the Effect of Prostate-Specific Antigen Testing on Treatment Receipt for Early-stage Prostate Cancer among Elderly Men
Category: Cancer Health Disparities
Conference Year: 2020
Abstract Body:
Purpose: To examine geographic variation in the effect of systematic pre-diagnosis annual prostate-specific
antigen (PSA) testing on the likelihood of undergoing expectant management, as well as the individual and
county-level characteristics underlying such variation among Medicare-eligible older men.
Methods: We analyzed patients aged 65 years or older from the linked Surveillance, Epidemiology, and End
Results (SEER)-Medicare database. The sample included men diagnosed with localized/regional (early-stage)
prostate cancer (PCa) from 2004-2007, with continuous fee-for-service Medicare coverage in the 60 months prior
to PCa diagnosis. Treatments were categorized into receipt of radiation therapy, radical prostatectomy,
cryotherapy, androgen-deprivation therapy (ADT) or expectant management within 2 years of diagnosis. Annual
PSA testing was stratified by the receipt of 0-1, 2-3 and 4 or more tests during the 5 years before PCa diagnosis.
Cluster-adjusted logistic regression models were used to quantify the effect of annual PSA testing on treatment
receipt controlling for patient and county characteristics. We assessed geographic variation in PCa treatment
outcomes using random intercept/slope models and variance partition coefficients.
Results: Among 35,362 older Medicare beneficiaries, 20% underwent expectant management within the first two
years of early-stage PCa diagnosis. Multivariate analyses showed that greater intensity of annual PSA testing was
associated with a statistically significant lower likelihood of undergoing expectant management compared to
receiving zero or one PSA test prior to diagnosis (4 or more times OR: 0.48, 95% CI 0.43-0.54; 2-3 times OR:0.64,
95% CI: 0.58-0.70). County of residence accounted for 2.5% of the variation in treatment receipt. The effect of
annual PSA-testing on treatment receipt varied across counties (p<0.003).
Conclusions: The use of expectant management among Medicare beneficiaries varied based on preventive health
behavior, patient demographic characteristics, and geographic location.
Keywords: prostate cancer screening and treatment, geographic disparities