PSMA + MRI Cuts False Negatives for Clinically Significant Prostate Cancer

Prostate-specific membrane antigen (PSMA) positron emission tomography combined with magnetic resonance imaging (MRI) reduces false negatives for clinically significant prostate cancer (csPCa) compared with MRI alone, according to a study published online in European Urology.

In a prospective multicenter phase II imaging trial, Louise Emmett, MBChB, from St. Vincent’s Hospital Sydney in Darlinghurst, Australia, and colleagues examined whether the combination of PSMA + MRI was superior to MRI alone for detecting csPCa. Two hundred ninety-six men with suspected prostate cancer and no prior biopsy or MRI were enrolled. All men underwent MRI within six months and were consented for transperineal biopsy based on clinical risk and MRI; 291 of the men underwent MRI, pelvic-only PSMA, and systematic ± targeted biopsy.

The researchers found that 56 percent of the patients (162 men) had csPCa; 67 percent had Prostate Imaging Reporting and Data System (PI-RADS) 3 to 5; and 73 and 81 percent were positive with PSMA and combined PSMA + MRI, respectively. The negative predictive value was improved with PSMA + MRI versus MRI alone (91 versus 72 percent; test ratio, 1.27). There was also an improvement in sensitivity (97 versus 83 percent), but specificity was reduced (40 versus 53 percent). PSMA + MRI missed five csPCa cases. Nineteen percent of the men were negative by PSMA + MRI (38 percent of PI-RADS 2/3) and could potentially have avoided biopsy, resulting in delayed detection of csPCa in five men (3.1 percent of men with csPCa [five/162] or 1.7 percent overall [five/291]).

“Further randomized studies will determine whether biopsy can safely be omitted in men with a high clinical suspicion of csPCa but negative combined imaging,” the authors write.

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