ORLANDO, FL USA (UroToday.com) - While multiple studies over the past several years have highlighted a role for multi-parametric prostate MRI and MRI-ultrasound fusion biopsy in evaluating men with prostate cancer, these modalities remain expensive and are not yet in widespread use. Targeted biopsy may have several advantages over template 12-core biopsy, including detection of cancer that may be more representative of final pathology, but indications for its use are not defined. In particular, it is unknown if any imaging findings may predict higher-grade disease on targeted biopsy versus 12-core biopsy. Delineating such identifiers could aid in the clinical decision process for using fusion biopsy.
In the first of several studies from the National Cancer Institute, Nabeel Shakir and colleagues report MP-MRI characteristics that predicted clinically-significant upgrading on targeted biopsy. This trial of 1 012 men was predicated on MRI-ultrasound fusion biopsy finding more high-grade cancers than 12-core biopsy, overall, and across pre-selected PSA cutoffs, with the proportion of clinically-significant cancers expected to increase with greater PSA. Both of these premises were borne out in the NCI population. More upgrading to clinically significant disease, defined as a Gleason sum of ≥ 4+3, was found in patients with PSA > 4-10 and > 10. Two multiparametric MRI findings were found to predict upgrading within these cutoffs specifically: MRI suspicion score and number of lesions. Lesions of moderate and high suspicion were more likely to represent significant disease, and a patient with PSA > 4 with more than 2 lesions was more likely to have high-grade cancer found by fusion biopsy.
These findings may represent the first method to refine decision-making for deploying MRI-ultrasound fusion biopsy; the population of men best served by this modality may be those with PSA > 4 and with more than 2 moderate- to highly-suspicious lesions on MP-MRI. As a further extension of this work, it may not be necessary to perform MP-MRI or targeted biopsies in patients with specific imaging findings or based on PSA level, potentially on the basis of a nomogram or algorithm. The authors explore this theme further in studies aimed at identifying a threshold PSA level to detect clinically-significant cancer.
Presented by Nabeel Shakir at the American Urological Association (AUA) Annual Meeting - May 16 - 21, 2014 - Orlando, Florida USA
National Cancer Institute, Bethesda, MD USA
Written by Jason T. Rothwax, National Cancer Institute