MRI-detected extranodal extension as a marker of prostate cancer aggressiveness.

[OBJECTIVE] Extranodal extension (ENE) is a histological marker of aggressiveness for various cancers. We evaluated if clinical ENE, detected by Magnetic Resonance Imaging, can also serve as a biological marker of Prostate Cancer (PCa) aggressiveness.

[MATERIALS AND METHODS] This retrospective, single-center study analyzed patients diagnosed with PCa and had MRI on a 3-T scanner from January 2013 to December 2017. After exclusions, 461 patients were included and divided into: Group 1, no lymph node involvement (LNI), Group 2 (LNI without ENE), and Group 3 (LNI and ENE). Two experienced radiologists assessed the MRI scans for primary lesion characteristics, LNI and ENE. Reproducibility assessment was calculated for ENE and PI-RADS. Clinical outcomes, including Overall Survival (OS), Specific Survival Rate (SSR), and Progression-Free Survival (PFS), were analyzed.

[RESULTS] Group 1 included 410 patients, Group 2, 32 patients, and Group 3, 19 patients. The prevalence of ENE was 4.1%. Significant differences between groups were observed for age, PSA, dPSA, ISUP scores, clinical risk stratification, and staging (all p < 0.01). The Kappa coefficient for ENE was 0.75 (95% CI: 0.56-0.90), and 0.48 (0.14-1.0) for PI-RADS. Cox proportional hazards model showed PSA (HR: 1.009; 95% CI = 1.003-1.015, p < 0.01) and ENE (HR: 8.50; 1.76-40.98, p < 0.01) were associated with SSR, and both ENE (HR: 8.18; 2.34-28.58, p < 0.01) and LNI (HR: 5.99, 1.97-18.17, p < 0.01) were linked to poor PFS.

[CONCLUSION] MRI-detected ENE, despite low prevalence, is a predictor of SSR and PFS in PCa. These findings support ENE as an independent prognostic marker. Further prospective, multi-institutional studies are required to validate these results.

[KEY POINTS] Question Pathological extranodal extension (pENE) has been described as a marker of worrisome prognosis in prostate cancer (PCa), but clinical ENE has not been evaluated as a marker of prognosis in PCa. Findings MRI-detected clinical ENE, had a low prevalence in our cohort (4.1%), but it was a predictor of specific survival rate and progression-free survival. Clinical relevance MRI-detected clinical ENE, a reproducible imaging feature, may serve as a non-invasive biomarker for aggressive prostate cancer. It correlates with poorer progression-free survival and specific survival rates, offering valuable prognostic insights for patient management.