By: Dan Sperling, M.D.

A groundbreaking study was published in 2006 by a French research team lead by Arnaud Villers, M.D. Dr. Villers is a distinguished expert in localized prostate cancer, having published over 100 papers on topics ranging from the clinical development of the disease to imaging and surgical anatomy. He has a particular interest in focal therapy techniques, for which proper patient selection is essential for success and monitoring. Thus, he has pursued the question of how to optimize imaging to aid the selection process.

The 2006 study examined how well one particular functional MRI parameter, dynamic contrast enhancement (DCE-MRI) correlates with actual prostatectomy specimens (glands that were surgically removed and examined by laboratory pathologists).[i] DCE-MRI, which involves the use of an injected contrast agent, is a well established method for revealing the abnormal microcirculation of a tumor’s blood vessels, thus pointing to the presence of a malignancy. The goal of the team’s research was to explore how well DCE-MRI can predict the location and volume of localized prostate tumors within the gland. By comparing interpretations of pre-surgical images with the actual evidence from the same glands after surgical removal (called “specimens”) the French team was able to analyze how correct the image readers were.

In the 2006 study, 24 patients scheduled for prostatectomy underwent T1-weighted DCE-MRI as well as T2 weighted MRI. Suspicious areas were assigned a malignancy score, and their locations were identified according to anatomical features, the side of the gland, and transition and peripheral zone boundaries. The largest surface area and volume were measured. These magnetic resonance imaging findings were compared with lab findings on the specimens.

The researchers selected two different size tumors for comparison with the lab reports: tumors greater than 0.2cc and tumors greater than 0.5cc. The actual specimens revealed 14 cases in which the largest tumor was located in the peripheral zone of the prostate; and in the other 10 cases the transition zone was involved. Based on what the imaging predicted, the results were as follows:

    ^aThe proportion of positives correctly identified as such

       ^bThe proportion of negatives correctly identified as such

^cThe probability that positive results are truly cancer

          ^dThe probability that negative results are truly not cancer

Based on the high percentages of PPV and NPV, the authors conclude that DCE-MRI “is an accurate technique for detecting and quantifying intracapsular transition or peripheral zone tumor foci greater than 0.2cc. It has promising implications for cancer detection, prognosis and treatment.”

Thus, the ability of DCE-MRI to locate tumors and gauge their size is a precursor to further testing and treatment. It allows physicians to counsel patients on further steps (diagnosis by biopsy) and to match the therapy to the patient’s disease.