The authors identified 157 lesions among 114 patients that met inclusion criteria from 2014-2017 who underwent mpMRI and targeted biopsy. To characterize lesion heterogeneity, only men with ≥2 positive targeted biopsy cores were included in the study. Histologic grades were scored according to International Society of Urological Pathology (ISUP) grades. Lesion heterogeneity was reported as a heterogeneity index (HI) and calculated as the difference of the average ISUP grades of targeted biopsy cores per lesion from the maximum sampled ISUP grade of that lesion. Maximum ISUP grade ranged from 1 to 5, with a median ISUP grade of 2. Higher ISUP grades were associated with greater lesion heterogeneity (HI for ISUP grade ≥3 = 0.58 ± 0.11 vs <3 = 0.29 ± 0.08, p = 0.0001). Second, increasing lesion size on mpMRI was associated with greater lesion heterogeneity (HI for ≥2cm = 0.52 ± 0.14 vs <2cm = 0.32 ± 0.08, p = 0.0096). Finally, higher mpMRI suspicion scores were associated with increased heterogeneity vs lower suspicion scores (0.46 ± 0.48 vs 0.31 ± 0.35; p = 0.033).
The authors concluded that mpMRI aids in characterizing prostate cancer lesion heterogeneity to predict variability of histologic grades on targeted. This information may assist targeted planning to potentially reduce risks of upgrading on final pathology. The authors noted that future research will examine how lesion heterogeneity can impact risk stratification and clinical decision-making for patients and practitioners.
Presented by: Samuel Gold, National Cancer Institute, Bethesda, MD
Co-Authors: Jonathan Bloom, Graham R. Hale, Kareem Rayn, Sherif Mehralivand, Brad J. Wood, Baris Turkbey, Peter A. Pinto
Written By: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA