Associations Between Prostate Magnetic Resonance Imaging, Genomic Testing, and Treatment for Localized Prostate Cancer.

Introduction: Although prostate MRI and tissue-based gene expression (genomic) tests improve staging and estimates of prostate cancer prognosis, their association with the intensity of treatment patients receive is not well understood.
Methods: We performed a retrospective cohort study of Medicare beneficiaries diagnosed with clinically localized prostate cancer in 2013 through 2017 in the Surveillance, Epidemiology, and End Results database. The primary study outcome was the receipt of treatment intensification in the first 12 months after diagnosis (defined as the addition of androgen deprivation therapy among patients receiving radiation or pelvic lymphadenectomy among those undergoing radical prostatectomy). We assessed associations between the receipt of prostate MRI and genomic testing and treatment intensification, adjusting for clinical and sociodemographic factors and further stratifying the analyses by risk status.
Results: We identified 37,064 patients with clinically localized prostate cancer, including 6398, 22,011, and 5976 with low, intermediate, and high D'Amico-risk disease, respectively. Among all treated patients, receipt of prostate MRI was associated with increased odds of treatment intensification (odds ratio 1.76, 95% CI 1.65-1.88, P < .001). In contrast, genomic testing was not significantly associated. Among treated patients with high-risk disease, genomic testing was associated with decreased odds of intensified treatment (odds ratio 0.59, 95% CI 0.35-1.00, P = .05).
Conclusions: Prostate MRI was associated with intensified treatment across risk strata, while genomic testing was associated with lower intensity of treatment among high-risk disease. Additional study is needed to determine whether use of imaging and risk stratification tools leads to improved long-term patient outcomes.