Introduction: Prostate magnetic resonance imaging (MRI) and tissue-based gene expression (genomic) tests improve local staging and estimates of disease prognosis, however clinical management associated with their use in the real-world setting is not well understood. Methods: We performed a retrospective cohort study of Medicare beneficiaries diagnosed with clinically localized prostate cancer in 2013-2017 and treated with prostate radiation or radical prostatectomy in the Surveillance Epidemiology and End-Results (SEER)-Medicare database. We identified prostate MRI and genomic tests using specific administrative claims codes. The primary study outcome was treatment intensification, defined as any use of androgen deprivation therapy (ADT) for prostate radiation or pelvic lymph node dissection (PLND) for radical prostatectomy, respectively. We assessed the associations between patient-level receipt of prostate MRI and genomic testing and treatment intensification via multivariable logistic regressions, adjusting for clinical and sociodemographic factors, and further stratifying the analyses by D’Amico clinical risk status. Results: We identified 26,017 patients meeting inclusion criteria, including 2,822 (11%) with low, 17,651 (68%) with intermediate and 4,664 (18%) with high-risk prostate cancer. In the overall cohort, receipt of prostate MRI (odds ratio [OR], 1.76 95% confidence interval [CI] 1.65-1.88, p<0.001) was associated with increased odds of treatment intensification, while genomic testing was not associated (OR 0.86, 95% CI 0.73-1.01, p=0.07). Prostate MRI was associated with increased odds of intensified treatment in all risk strata, while genomic testing was associated with lower odds of intensified treatment in the high-risk subset only (OR 0.59, 95% CI 0.35-1.00, p=0.048). By specific treatments, prostate MRI was associated with increased odds of PLND (OR 2.54, 95% CI 2.24-2.87) and ADT (OR 1.37, 95% CI 1.26-1.48) across all risk strata, while genomic testing was associated with decreased odds of PLND (OR 0.67, 95% CI 0.54-0.83) and ADT (OR 0.55, 95% CI 0.41-0.76). This analysis is limited by the absence of MRI and genomic testing results. Conclusions: We identified distinct patterns of management associated with prostate MRI and genomic testing in localized prostate cancer. These findings suggest the need for additional information about the independent role of diagnostic technologies in decision-making. SOURCE OF Funding: William O. Seery Foundation, Patterson Trust Mentored Research Award NIH/National Cancer Institute
