| Sumario: | Simple Summary: Our work evaluates a recent MRI scoring system (Prostate Imaging after Focal Ablation, PI-FAB) designed to detect recurrent prostate cancer after focal therapy. Focal therapy targets only cancer in the prostate without treatment to the whole prostate, performed for patients with intermediate risk prostate cancer. Monitoring patients after focal therapy is challenging because the prostate tissue becomes distorted and difficult to interpret on MRI. Our team reviewed follow-up MRI scans and biopsy results from men after focal treatment. Two radiologists with different levels of experience independently used PI-FAB to detect cancer recurrence. Overall, PI-FAB performed well in reliably identifying cancer recurrence. The more experienced radiologist achieved slightly better results, suggesting that specialist experience improves interpretation accuracy. The study concludes that PI-FAB is a promising and practical tool for standardizing MRI surveillance after focal prostate cancer therapy, potentially improving consistency in follow-up care and detecting recurrent disease more reliably. Focal therapy (FT) for localized prostate cancer induces architectural changes that complicate post-treatment multiparametric magnetic resonance imaging (mpMRI) surveillance. The Prostate Imaging after Focal Ablation (PI-FAB) system was developed to standardize the evaluation of in-field recurrence on mpMRI. This study assessed the diagnostic performance and inter-reader agreement of PI-FAB following focal cryoablation for localized prostate cancer. In this retrospective study (October 2019 to January 2024), 85 patients (140 lesion sites) underwent post-FT mpMRI and biopsy. Two radiologists (11 and 4 years of experience) independently scored mpMRIs using the three-point PI-FAB scale. Metrics included sensitivity, specificity, PPV, NPV, and accuracy. Inter-reader agreement was measured via quadratic weighted Cohen's kappa (κ). Reader 1 (more experienced) demonstrated 83.9% sensitivity, 84.4% specificity, 60.5% PPV, and 94.8% NPV. Reader 2 demonstrated 71.4% sensitivity, 87.5% specificity, 58.8% PPV, and 92.5% NPV. Both achieved 84.3% accuracy. Inter-reader agreement was moderate (κ = 0.60). PI-FAB provides good diagnostic performance for detecting in-field recurrence after cryoablation. While reader experience may impact sensitivity, moderate agreement across experience levels supports PI-FAB's validity and potential clinical utility in standardizing post-FT surveillance.
|