A prospective study evaluating indirect MRI-signs for the prediction of extraprostatic disease in patients with prostate cancer: tumor volume, tumor contact length and tumor apparent diffusion coefficient

The aim of this study was to evaluate three indirect MRI signs for predicting extraprostatic disease in patients referred to radical prostatectomy: index tumor volume (MTV), apparent diffusion coefficient (ADC) and tumor contact length (TCL).

This prospective study included 183 patients with biopsy proven prostate cancer. In all patients the MTV (ml), ADC (× 10-5 mm2/s) and TCL (mm) of the index tumor were registered at the preoperative MRI. Whole-mounted microscopical examination classified each patient as having either localized- or extraprostatic disease. The Youden index was used to identify the optimal cut-off values for predicting extraprostatic disease. Univariate regression analyses were conducted to estimate the odds ratio (OR) with 95% confidence intervals (CI). Results were stratified upon zonal location of the index tumor.

Extraprostatic disease was identified in 103 (56%) patients. The risk of extraprostatic disease was nine times higher in peripheral zone tumors with ADC ≤ 89 (OR 9.1, 95% CI 4.2-19.6), five times higher in MTV ≥ 0.9 ml (OR 5.5, 95% CI 2.6-11.4) and five times higher in case of TCL ≥ 14 mm (OR 4.9, 95% CI 2.3-10.2). None of the indirect MRI signs could predict extraprostatic disease for transition zone tumors.

The MTV, ADC and TCL are all significant predictors of extraprostatic disease for peripheral zone tumors, while none of the indirect signs were useful for transition zone tumors.

World journal of urology. 2018 Jan 18 [Epub ahead of print]

Erik Rud, Lien Diep, Eduard Baco

Division of Radiology and Nuclear Medicine, Oslo University Hospital, Aker, Nydalen, Post box 4959, 0424, Oslo, Norway. ., Oslo Centre for Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway., Division of Surgery, Inflammatory Diseases and Transplantation, Department of urology, Oslo University Hospital, Oslo, Norway.