Assessing cancer risk in the anterior part of the prostate using micro-ultrasound: validation of a novel distinct protocol

Purpose To develop and validate a micro-ultrasound risk score that predicts the likelihood of significant prostate cancer in the anterior zone.

Methods Patients were enrolled from three expert institutions familiar with micro-ultrasound.

The study was conducted in two phases.

First, the PRI-MUS anterior score was developed by assessing selected prostate videos from patients who subsequently underwent radical prostatectomy.

Second, seven urology readers with varying levels of experience in micro-ultrasound examination evaluated prostate loops according to the PRI-MUS anterior score.

Each reader watched the videos and recorded the likelihood of the presence of significant cancer in the anterior part of the prostate in a three-point scale.

The coherence among the readers was calculated using the Fleiss kappa and the Cronbach alpha.

Results A total of 102 selected prostate scans were used to develop the risk assessment for anterior zone cancer in the prostate.

The score comprised three categories: likely, equivocal, and unlikely.

The median (IQR) sensitivity, specificity, positive predictive value, and negative predictive value for the seven readers were 72% (68–84), 68% (64–84), 75% (72–81), and 73% (71–80), respectively.

The mean SD ROC AUC was 0.75 ± 2%, while the Fleiss kappa and the Cronbach alpha were 0.179 and 0.56, respectively.

Conclusion Micro-ultrasound can detect cancerous lesions in the anterior part of the prostate.

When combined with the PRI-MUS protocol to assess the peripheral part, it enables an assessment of the entire prostate gland.

Pending external validation, the PRI-MUS anterior score developed in this study might be implemented in clinical practice.