Expanding inclusion criteria for active surveillance in intermediate-risk prostate cancer: a machine learning approach.

PURPOSE: To develop new selection criteria for active surveillance (AS) in intermediate-risk (IR) prostate cancer (PCa) patients. METHODS: Retrospective study including patients from 14 referral centers who underwent pre-biopsy mpMRI, image-guided biopsies and radical prostatectomy. The cohort included biopsy-naive IR PCa patients who met the following inclusion criteria: Gleason Grade Group (GGG) 1-2, PSA < 20 ng/mL, and cT1-cT2 tumors. We relied on a recursive machine learning partitioning algorithm developed to predict adverse pathological features (i.e., ≥ pT3a and/or pN + and/or GGG ≥ 3). RESULTS: A total of 594 patients with IR PCa were included, of whom 220 (37%) had adverse features. PI-RADS score (weight:0.726), PSA density (weight:0.158), and clinical T stage (weight:0.116) were selected as the most informative risk factors to classify patients according to their risk of adverse features, leading to the creation of five risk clusters. The adverse feature rates for cluster #1 (PI-RADS ≤ 3 and PSA density < 0.15), cluster #2 (PI-RADS 4 and PSA density < 0.15), cluster #3 (PI-RADS 1-4 and PSA density ≥ 0.15), cluster #4 (normal DRE and PI-RADS 5), and cluster #5 (abnormal DRE and PI-RADS 5) were 11.8, 27.9, 37.3, 42.7, and 65.1%, respectively. Compared with the current inclusion criteria, extending the AS criteria to clusters #1 + #2 or #1 + #2 + #3 would increase the number of eligible patients (+ 60 and + 253%, respectively) without increasing the risk of adverse pathological features. CONCLUSIONS: The newly developed model has the potential to expand the number of patients eligible for AS without compromising oncologic outcomes. Prospective validation is warranted.

Grade group 1 prostate cancer on biopsy: are we still missing aggressive disease in the era of image-directed therapy?

PURPOSE: Recently, Eggener et al. reignited a debate consisting to redefine Gleason Grade Group (GGG) 1 prostate cancer (PCa) as a precancerous lesion to reduce overdiagnosis and overtreatment. However, historical cohorts showed that some GGG1-labeled disease at biopsy may be underestimated by the standard PCa diagnostic workup. The aim was to assess whether the risk of adverse features at radical prostatectomy (RP) in selected GGG1 patients still exists in the era of pre-biopsy mpMRI and image-guided biopsies. METHODS: We retrospectively reviewed our data from a European RP dataset to assess in contemporary patients with GGG1 at mpMRI-targeted biopsy the rate of adverse features at final pathology, defined as ≥ pT3a and/or pN+ and/or GGG ≥ 3. RESULTS: A total of 419 patients with cT1-T2 cN0 GGG1-PCa were included. At final pathology, 143 (34.1%) patients had adverse features. In multivariate analysis, only unfavorable intermediate-risk/high-risk disease (defined on PSA or stage) was predictive of adverse features (OR 2.45, 95% CI 1.11-5.39, p = 0.02). A significant difference was observed in the 3-year biochemical recurrence-free survival between patients with and without adverse features (93.4 vs 87.8%, p = 0.026). In sensitivity analysis restricted low- and favorable intermediate-risk PCa, 122/383 patients (31.8%) had adverse features and no preoperative factors were statistically associated with this risk. CONCLUSION: In this European study, we showed that there is still a risk of underestimating GGG1 disease at biopsy despite the routine use of image-guided biopsies. Future studies are warranted to improve the detection of aggressive disease in GGG1-labeled patients by incorporating the latest tools such as genomic testing or radiomics.