Comparison of the Prostate Imaging After Focal Ablation (PI-FAB) and Transatlantic Recommendations for Prostate Gland...

Focal therapy (FT) for intermediate-risk, clinically localized unifocal prostate cancer (PCa) offers a tissue-sparing alternative to radical treatment with fewer adverse effects. However, post-FT surveillance remains challenging due to difficulty distinguishing fibrosis from residual tumor on multiparametric MRI (mpMRI). The PI-FAB and TARGET scoring systems were proposed to improve detection of clinically significant PCa (cs-PCa) recurrence. This study compares their diagnostic performance and real-world validation.

We retrospectively reviewed 111 men treated with FT (HIFU or cryotherapy) between 2019 and 2023, 31 of which met criteria for analysis with post-FT mpMRI and targeted/systematic prostate biopsies. Post-treatment mpMRI were scored using PI-FAB and TARGET systems. The primary outcome was detection of in-field cs-PCa (Grade Group ≥ 2) recurrence on biopsy. Diagnostic accuracy, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), was calculated for each scoring system.

The mean age was 67 years; 75% received HIFU and 25% cryotherapy. Eight men (26%) had cs-PCa on post-treatment biopsy, with 5 (16%) in-field recurrences. The PI-FAB and TARGET systems showed modest accuracy for in-field cs-PCa with AUCs of 0.66 and 0.62, respectively. Sensitivity was 60% (PI-FAB) and 40% (TARGET), specificity was 73% and 85%, PPV was 30% and 33%, and NPV was 90% and 88%, respectively.

The PI-FAB and TARGET mpMRI scoring systems demonstrate limited sensitivity but high NPV in detecting in-field cs-PCa recurrence after FT. These results highlight the limitations of current mpMRI interpretation protocols post-FT and the need for improved surveillance tools to guide biopsy decisions.