DIAGNOSTIC ACCURACY OF IXIP INDEX AND PROSTATE MRI IN THE DIAGNOSIS OF PROSTATE CANCER: PRELIMINARY RESULTS ON A COMBINED APPROACH

Abstract

The purpose of this study was to assess whether Immune CompleX Predictive Index (iXip)

improves diagnostic accuracy of multiparametric prostate MRI (mpMRI) for clinically significant

prostate cancer. This study included 72 patients (mean age: 68±8 years) with suspicion of prostate

cancer and available iXip score. mpMRI images were evaluated by two radiologists according to

the PI-RADS v2.1. Reference standard was based on fusion biopsy and standard transperineal 12-

point biopsy. Diagnostic accuracy of iXip, mpMRI and their combination were calculated. Optimal

cutoff of iXip with sensitivity and specificity was identified using the Youden index. Patients with

clinically significant prostate cancers had significantly higher iXip values compared to patients

without clinically significant prostate cancers (median 0.411 vs 0.273; p=0.026). The AUROC for

iXip was 0.795 (95% CI 0.579-1.000, p=0.026). Sensitivity and specificity were 75% and 100%

respectively for mpMRI alone, and 100% and 80% respectively for mpMRI combined with iXip >

0.375. The combination of mpMRI with a cutoff value of iXip > 0.375 has a very high sensitivity

for the diagnosis of prostate cancer and a moderately high specificity.