To evaluate the association between prostate magnetic resonance imaging (MRI) and the use of observation for men with low-risk prostate cancer (PCa).

We used the Surveillance, Epidemiology, and End Results-Medicare database to identify men diagnosed with low-risk PCa during 2010-2013. We assessed the use of prostate MRI and management using claims in period surrounding PCa diagnosis. The relation of clinical and demographic factors to receipt of MRI was evaluated with multivariable logistic regression analysis. Following propensity score matching, we fit conditional logistic regression models to examine the association between prostate MRI and initial management, ie, observation or definitive treatment.

Of 8144 patients with low-risk PCa, 495 (6.1%) received MRI. Use of MRI increased from 3.4% in 2010 to 10.5% in 2013. A total of 3060 (37.6%) patients received observation. MRI was performed in 265 (8.7%) of patients receiving observation, and 230 (4.5%) who were treated (P < .0001). In multivariable analysis, measures of socioeconomic status were significantly associated with the use of prostate MRI. Following propensity score matching, receipt of prostate MRI surrounding the diagnosis of PCa was associated with a significantly higher likelihood of observation (odds ratio = 1.90, 95% confidence interval: 1.56-2.32). This effect persisted in sensitivity analyses attempting to exclude treatment-planning MRIs.

Receipt of prostate MRI surrounding PCa diagnosis was associated with a nearly 2-fold greater odds of receiving observation vs definitive treatment.