Aggressiveness of Prostate Tumors Assessed with Magnetic Resonance Spectroscopic Imaging

Researchers from the Radboud University Nijmegen Medical Centre (Nijmegen, The Netherlands) have investigated the performance of magnetic resonance spectroscopic imaging (MRSI) as a technique for assessing the aggressiveness of prostate tumors. Led by Thiele Kobus of the University’s Department of Radiology, the team compared the findings obtained through MRSI to the Gleason score (which evaluates the prognosis of prostate cancer on a number scale) of radical prostatectomy (RP) specimens, and determined that MSRI provides a noninvasive alternative for determining tumor aggressiveness.

Current screening methods detect prostate-specific antigen levels with a mortality reduction rate of 20%; however, these methods often lead to overdiagnosis and overtreatment of indolent cancers, causing unnecessary side effects. In the study, which was published in the online edition of European Urology on March 11, 2011, the team states that the current screening method — transrectal ultrasound (TRUS)-guided biopsies that determine the Gleason score — often underestimate the aggressiveness of the tumor. Because prostate cancer tissue contains lower levels of citrate and/or higher levels of choline than normal tissue, the team used proton magnetic resonance spectroscopy to determine the ratio of these metabolites in the tumor tissue and compared it to the Gleason score.

The team determined that MRSI scans successfully detect the choline and creatine to citrate ratios to accurately assess the aggressiveness of the tumor. They conclude that MSRI can be used as a noninvasive, prognostic technique that not only differentiates between indolent and aggressive tumors, but can also guide physicians to the most aggressive area of the tumor.