The combination of multiparametric MRI and the recently revised Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) misses a “considerable number” of clinically significant prostate cancer (PCA) lesions, according to a new study published in the American Journal of Roentgenology. The authors noted, however, that the high positive predictive value (PPV) might make this method useful for imaging active surveillance (AS) patients.
To evaluate the performance of multiparametric MRI with PI-RADSv2, the authors studied data from 93 PCA lesions from 44 patients who underwent radical prostatectomy. Two radiologists assigned a PI-RADSv2 score of 3, 4 or 5 to each visible lesion from the multiparametric MRI. PPV, negative predictive value (NPV) and area under the ROC curve (AUC) value were all determined.
Overall, more than 46 percent of clinically significant PCA lesions were detected using this method. The PPV was more than 96 percent, the NPV was more than 45 percent and the AUC was 0.72.
“Multiparametric MRI with PI-RADSv2 missed a considerable number of clinically significant PCA lesions in this per-lesion analysis,” wrote lead author Myoung Seok Lee, MD, BS, Seoul National University Boramae Medical Center in Seoul, South Korea, and colleagues. “We found a relatively low NPV and diagnostic performance compared with the per-patient results reported in previous studies.”
The high PPV, Lee and colleagues added, shows that this method has potential for follow-up of patients undergoing AS.
“It seems that PI-RADSv2, as a simplified reporting system, provides greater PPV than previous systems, for both per-patient and per-lesion analyses,” the authors wrote. “Although patient enrollment in studies of AS is on a per-patient basis, follow-up results of enrolled patients could be reported on a per-lesion basis because a new lesion or a lesion showing interval change can lead to initiation of active treatment or the patient can remain in the AS program.”
Multiparametric MRI with PI-RADSv2 could also potentially be used during AS follow-up instead of the annual prostate biopsy. Both methods miss a similar number of clinically significant PCAs, but patient morbidity and quality of life are “much better” with multiparametric MRI than with biopsy.
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.