Prognosis of men with high-risk prostate cancer stratified by risk factors: a population-based retrospective cohort study

Background: The aim was to evaluate the prognosis of men with all possible high-risk prostate cancers (PCa) stratified by risk factors. Methods: Within the Surveillance, Epidemiology and End Results (SEER) database from 2004 to 2015, men with non-metastasis high-risk PCa were identified. Kaplan-Meier analysis and Cox regressions were adopted to evaluate the overall survival (OS) and prostate cancer-specific survival (PCSS). Nomograms were conducted to build a predictive model. Concordance index (C-index) and calibration curves were used to validate the model. Results: A total of 151,799 patients were included. Seven risk groups were divided including one high-risk factor of T3-4 (A1), prostate-specific antigen (PSA) >20 ng/mL (A2), and Gleason score (GS) 8-10, two high-risk factors of T3-4 PSA >20 ng/mL (B1), T3-4 GS 8-10 (B2), PSA >20 ng/mL GS 8-10 (B3), and three high-risk factors of T3-4 PSA >20 ng/mL GS 8-10 (C). The survival curves of PCSS showed that Al was the best among all groups. A2, A3 and B1 had similar results and were all better than B2 [with A2 as reference, A3 hazard ratio (HR): 1.09 (1.02-1.17), P=0.046; B1 HR: 0.93 (0.82-1.05), P=0.103; B2 HR: 1.42 (1.32-1.53), P<0.001]. There is no significant difference between B3 and C [HR: 0.94 (0.86-1.03), P=0.029] and these two present the worst survival in prognosis. The 10-year PCSS of A1, A2, A3, B1, B2, B3, and C groups were 95.8%, 86.9%, 86.1%, 86.9%, 80.8%, 64.7% and 65.6%, respectively. Three simplified groups were divided including a good prognosis group (A1), an intermediate prognosis group (A2, A3, B1 and B2), and a poor prognosis group (B3 and C). Compared to the good prognosis group, the HR of the intermediate and the poor prognosis group were 4.21 (3.96-4.48), P<0.001 and 11.36 (10.59-12.19), P<0.001. A nomogram was built based on these factors. The C-index of the nomogram was 0.772, indicating a good accuracy of the model. Conclusions: Men with the combination of PSA >20 ng/mL and GS 8-10 had the worst PCSS among all patients. PCa with three high-risk factors was not more aggressive than that with two high-risk factors of GS 8-10 and PSA >20 ng/mL.