The role of the size and number of index lesion in the diagnosis of clinically significant prostate cancer in patients with PI-RADS 4 lesions detected by multiparametric MRI of the prostate.

Abstract

Purpose: To evaluate the contribution of the size and number of the sampled lesions to the diagnosis of clinically significant prostate cancer (CSPC) in patients who had PI-RADS 4 lesions. Methods: In this retrospective study, a total of 159 patients who had PI-RADS 4 lesions and underwent In-bore MRI-Guided prostate biopsy were included. Patients with a lesion classified as Grade Group 2 and above were considered to have CSPC. Univariate and multivariate regression analyses were used to evaluate the factors affecting the diagnosis of prostate cancer (PCa) and CSPC. Results: A great majority (86.8%) of the patients were biopsy-naïve. About three-fourths (71.7%) had PCa, and half (54.1%) had CSPC. When the patients were divided into three groups according to the index lesion size (< 5 mm, 5-10 mm, and > 10 mm), the prevalence of PCa was 64.3, 67.5, and 82.4% and the prevalence of CSPC was 42.9, 51.2, and 64.7%, respectively. In multivariate analysis, age, index lesion size, prostate volume (< 50 ml) and being biopsy-naïve were found significant for PCa, while age and prostate volume (< 50 ml) were significant for CSPC. Conclusion: The number of lesions was found to be insignificant in predicting PCa and CSPC. While the size of PI-RADS 4 lesions was significant in predicting PCa, it had no significance in detecting CSPC.