How good is post-biopsy multiparametric magnetic resonance imaging in detecting and characterising the index lesion of localised prostate cancer?

Abstract

Objective. The aim of this study was to evaluate the accuracy of multiparametric endorectal magnetic resonance imaging (mp-MRI) in detecting and characterising the largest tumour lesion, which is defined as the index tumour of prostate cancer. Material and methods. A total of 55 patients with proven histological prostate cancer underwent post-biopsy MRI at 1.5 T and subsequent radical prostatectomy. The maximum tumour diameter (MTD) of the index lesion was determined independently by MRI and histopathology in a prospective manner. The detection rate of the index lesion, the MTD and volume by pathology, and the pathological tumour (pT) stage were correlated with the MTD by MRI using Pearson's correlation. Results. Pathohistology revealed 158 cancer foci. MRI detected 55 foci. The sensitivity, specificity, accuracy, and negative and positive predictive values of mp-MRI for index lesion detection were 89%, 100%, 90%, 44% and 100%, respectively. Three positive correlations were found: one between the MTD of the index lesion by MRI and the MTD by pathology (Pearson coefficient = 0.890, p < 0.01), a second between the MTD by MRI and the index tumour volume at pathology (Pearson coefficient = 0.786, p < 0.01), and a third between the MTD and the pT stage (Pearson coefficient = 0.678, p < 0.01). Conclusion: mp-MRI can accurately detect the index lesion and estimate the TVP of localised prostate cancer.