Ruling out clinically significant prostate cancer with negative multi-parametric MRI

Purpose

To evaluate the negative predictive value (NPV) of a negative prostate multi-parametric magnetic resonance imaging (mpMRI) in ruling out clinically significant prostate upon 12-core systematic biopsy.

Methods

We retrospectively reviewed 114 men evaluated at our institution who underwent systematic 12-core biopsy within 1 year of a negative prostate mpMRI. Clinicopathologic features were evaluated and NPV was calculated for detection of clinically significant (Gleason ≥ 7) cancer. Regression analysis was performed to identify clinical predictors of biopsy outcome.

Results

Overall, 88 (77.2%) patients in our cohort had no cancer detected upon biopsy. The highest pathologic grade was Gleason 6 (3 + 3) in 22 (19.3%) patients, and Gleason ≥ 7 in 4 (3.6%) patients. NPV for detecting Gleason ≥ 7 cancer was 96.5% (95% CI 93.1–99.9%) in the entire negative MRI cohort, 100% in those who were prostate biopsy naïve (n = 20), 100% in those with a prior negative biopsy (n = 53), and 90% in those who have had a previous positive biopsy and on active surveillance (n = 41). Regression analysis identified no predictors of significant cancer in our cohort.

Conclusion

In our cohort of men with no lesions detected on prostate mpMRI, we found very low rates of clinically significant cancer on systematic 12-core biopsy. In the few patients who diagnosed with prostate cancer, the majority had low-risk disease and could remain on active surveillance. Although validation studies and greater sample size is needed before clinical recommendations can be made, our data suggest patients with negative mpMRI evaluated by experienced radiologists may avoid unnecessary prostate biopsy and potential overtreatment.