Improving the Stratification of Patients With Intermediate-risk Prostate Cancer

Background: Intermediate-risk prostate cancer (IR PCa) phenotypes may vary from favorable to unfavorable. National Comprehensive Cancer Network (NCCN) criteria help distinguish between those groups. We studied and attempted to improve this stratification.

Patients and methods: A total of 4048 (NCCN favorable: 2015 [49.8%] vs. unfavorable 2033 [50.2%]) patients with IR PCa treated with radical prostatectomy were abstracted from an institutional database (2000-2018). Multivariable logistic regression models predicting upstaging and/or upgrading (Gleason Grade Group [GGG] IV-V and/or ≥ pT3 or pN1) in IR PCa were developed, validated, and directly compared with the NCCN IR PCa stratification.

Results: All 4048 patients were randomly divided between development (n = 2024; 50.0%) and validation cohorts (n = 2024; 50.0%). The development cohort was used to fit basic (age, prostate-specific antigen, clinical T stage, biopsy GGG, and percentage of positive cores [all P < .001]) and extended models (age, prostate-specific antigen, clinical T stage, biopsy GGG, prostate volume, and percentage of tumor within all biopsy cores [all P < .001]). In the validation cohort, the basic and the extended models were, respectively, 71.4% and 74.7% accurate in predicting upstaging and/or upgrading versus 66.8% for the NCCN IR PCa stratification. Both models outperformed NCCN IR PCa stratification in calibration and decision curve analyses (DCA). Use of NCCN IR PCa stratification would have misclassified 20.1% of patients with ≥ pT3 or pN1 and/or GGG IV to V versus 18.3% and 16.4% who were misclassified using the basic or the extended model, respectively.

Conclusion: Both newly developed and validated models better discriminate upstaging and/or upgrading risk than the NCCN IR PCa stratification.