Multiparametric magnetic resonance imaging (MRI) may enable doctors to predict the likelihood of biochemical recurrence of prostate cancer (PCa) after radical prostatectomy, Japanese researchers reported.

In a retrospective study that included 314 patients who underwent standard or laparoscopic radical prostatectomy, Seiya Hattori, MD, of the Keio University School of Medicine in Tokyo, and colleagues demonstrated that positive findings on preoperative multiparametric MRI scans were significantly associated with a high clinical stage (cT2 or higher), a high positive biopsy core rate (greater than 0.2), a high biopsy Gleason score (8 or higher), and a high pathologic Gleason score (8 or higher). In multivariate analyses, positive findings on MRI were associated with a significant sixfold increased odds of biochemical recurrence compared with negative findings, the researchers reported online ahead of print in BJU International.

In addition, the study revealed that a pathologic Gleason score of 8 or higher was associated with a significant threefold increased odds of recurrence compared with a score of 7 or less. Positive surgical margins (PSM) were associated with a nearly fourfold increased odds of recurrence compared with negative surgical margins.

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“In terms of the clinical impact of the present findings,” the authors wrote, “MRI positivity is an independent, brief and non-invasive biomarker which can predict therapeutic effects preoperatively.”

The investigators stated that MRI positivity “may have the potential to be an effective index for determination of a therapeutic strategy, as well as a follow-up strategy. This can be of benefit for clinicians as a strong- and easy-to-use predictive factor.”

The researchers used the variables significantly associated with biochemical recurrence to stratify patients into low-, intermediate-, and high-risk groups. Low-risk patients had zero or one risk factor (PSM or pathological Gleason score of 8 or higher); intermediate-risk patients had one risk factor (MRI positivity) or two risk factors (PSM or pathological Gleason score of 8 or higher); the high-risk group consisted of all other patients. The five-year biochemical recurrence-free rates were 99% in the low-risk group, 92% in the intermediate-risk group, and 72% in the high-risk group.

In a separate development involving the use of multiparametric MRI for PCa, another team of Japanese researchers demonstrated that this imaging technique can improve detection of anterior prostate tumors missed by transrectal 12-core biopsy.

The study, published in The Journal of Urology (2013;190:867-873), included 324 men underwent prebiopsy multiparametric MRI and then 3D 26-core prostate biopsy, a combination of transrectal 12-core and transperineal 14-core biopsy.

The overall cancer detection rate on 3-D 26-core prostate biopsy was 39%. Of these cancers, 28% were transrectal 12-core negative cancers, which the investigators defined as cancer detected by transperineal 14-core but not transrectal 12-core biopsy. Among men with and without an anterior lesion on MRI, 40% and 3.8%, respectively, had transrectal 12-core negative cancer. Prebiopsy multiparametric MRI revealed an anterior lesion in 92% of cases of significant transrectal 12-core negative cancer.