Introduction: Major technical improvements in multiparametric MRI (mpMRI) of prostate with the standard approach to interpretation using the PI-RADS v2 offers reliable visualization of potentially clinically significant prostate cancer (csPca) and thus has shown advantages as a means by which to better select patients for biopsy and facilitate direct targeting of lesions during biopsy.
However, currently available data show that the actual prevalence of csPCa after targeted biopsy in PI-RADS 3 lesions vary from 16% to 21%. We hypothesize that biomarkers such as PHI may better stratify a higher risk subgroup that harbor csPCa in patients with PI-RADS 3 lesions.
Methods: Patients with at least one PI-RADS = 3 lesion on mpMRI were enrolled for cognitive MRI-TRUS fusion-targeted prostate biopsy. All these patients had either PSA greater than 4 ng/ml and/or suspicious digital rectal examination (DRE) and/or previous negative systematic transrectal ultrasound (TRUS) prostate biopsy. All patients had received PHI test before the prostate biopsy. AUC under the ROC curves were estimated for the various PSA derivatives, along with the specificity at a pre-specified sensitivity of 90%.
Results: As PI-RADS 3 lesions have relatively low rates of csPCa and may present a new “grey zone” cognitive MRI-TRUS fusion-targeted prostate biopsy. Adding PHI to mpMRI improved predictive performance for overall PCa (AUC 0.818, CI 0.702-0.934) and csPCa detection (AUC 0.881, CI 0.787-0.975). The PHI alone was a significant predictor for any cancer (OR 5.95, 95% CI 1.35–42.36, p = 0.026) and significant cancers (OR 12.41, 95% CI 3.06–28.4, p < 0.001) after adjusting for age, prostate volume, previous negative biopsy and abnormal DRE in logistic regression. We found the optimal cutoff to be = 39.7 which would allow 39.3 % of patients to avoid biopsy. At this level, no csPCa was missed and both sensitivity and NPV were 100%.
Conclusions: In patients with PI-RADS 3 index lesions, which is a gray zone for PI-RADS v2, PHI exhibits outstanding performance in predicting csPCa. Using a PHI cutoff of = 39.7, up to 39 % of prostate biopsy could be avoided in patients with PI-RADS 3 lesions and no csPCa will be missed. Source of