Introduction:

Confirm MDx (MDx) is an epigenetic tissue test that analyzes benign prostate cores for tumor associated DNA promoter hypermethylation to geographically localize occult tumor. Multiparametric MRI (MRI) is useful for the detection of large or high-grade tumors. The purpose of our study was to evaluate the intersection of MRI and MDx in patients with a negative prostate biopsy.

Methods:

After IRB approval, patients referred on January 2017-December 2017 with elevated PSA and negative prostate biopsy prospectively underwent MDx and 1.5T MRI. MRI was centrally re-reviewed and PIRADS V2 score was assigned. Geographical concordance was defined as MDx and MRI abnormality in the same or neighboring sextant of the prostate.

Results:

A total of 202 patients were assessed. 111 patients (55%) had a positive MDx and 91 (47%) had a negative MDx. Of the patients with a positive MDx, 59 (53%) had a positive MRI. In this cohort, patients with PIRADS 3 lesions had a 65% geographical concordance with MDx. Of patients with PIRADS 4 and 5 lesions with + MDx, 89% were geographically concordant. All geographically discordant PIRADS 4 or 5 lesions in the + MDx group were in the anterior prostate. Biopsy results in patients with + MDx and PIRADS 3 lesions were found to have atypia (HGPIN or ASAP) in 56% and prostate cancer in 35.3% of cases. Patients with PIRADS 4 or 5 lesions had atypia in 22.7% and cancer in 63% when geographically concordant and 40.0% and 60.0% when lesion was discordant. Of the 91 patients with - MRI, 16 (17%) had a PIRADS 4 or 5 lesions. The lesion was in the anterior prostate in 80% of these patients. Predictors of PIRADS 4-5 lesions on MRI in patients with negative MDx are increased PSA and large prostate volume (all p values <0.05).

Conclusion:

Routine anterior sampling during systematic biopsy should be done to enhance the detection ability of MDx. . In patients with negative MDx, an MRI should be considered if PSA>10, PSAD >0.15 and/or the gland is large. Atypia may explain MDx false positives.

Funding: N/A