Clinicopathologic features and prognosis of incidental prostate cancer after radical cysto-prostatectomy: a comparative study between China and the West.

Background: Bladder cancer (BCa) is one of the most common tumors of the urinary system, imposing a significant societal burden. BCa is categorized into muscle-invasive BCa (MIBC) and non-MIBC (NMIBC) types. Radical cystoprostatectomy (RCP) is the standard treatment for MIBC and refractory NMIBC, but it can lead to serious side effects. Incidental prostate cancer (IPCa) is frequently found in RCP specimens, with varying incidence rates across ethnic groups, ranging from 7.3% to 60%. The clinical significance is unclear, and disparities in incidence and tumor characteristics exist within the Chinese population. The impact of IPCa on survival is debated, highlighting the need for research on its incidence and pathology for tailored interventions. This study aimed to compare the clinicopathological characteristics and prognostic significance of IPCa in RCP specimens taken from Chinese and Western BCa populations.

Methods: Data from patients who underwent RCP in our hospital between 2008 and 2022 were collated and compared to data from the Surveillance, Epidemiology, and End Results (SEER) database between 2008 and 2019. Chi-squared and non-parametric testing were conducted with survival analysis to investigate differences between IPCa traits and their impact on prognosis.

Results: Twenty-four IPCa cases were detected in 300 patients undergoing RCP, with a median age of 73 [interquartile range (IQR), 67-77] years. The median prostate-specific antigen (PSA) value was 2.81 (IQR, 1.19-4.81) ng/mL. 66.6% (n=16) had Gleason score (GS) ≤6 and all patients were stage T2. There were 315 IPCa patients in the 'Western' sample, with a median age of 68 (IQR, 63-74) years. The median PSA value was 1.9 (IQR, 0.9-4.1) ng/mL. 64.8% (n=204) had GS ≤6 and 93.0% (n=293) were stage T2. Comparative analysis showed that the clinicopathological features of IPCa were similar. Cox's regression analysis showed that T stage [hazard ratio (HR), 1.846; 95% confidence interval (CI): 1.394-2.444; P<0.001] and N stage (HR, 1.416; 95% CI: 1.011-1.984; P=0.04) of BCa were independent risk factors for cancer-specific survival (CSS). Advanced age (HR, 1.043; 95% CI: 1.018-1.069; P=0.001), T stage (HR, 1.569; 95% CI: 1.281-1.922; P<0.001), and N stage (HR, 1.317; 95% CI: 1.012-1.716; P=0.04) were independent risk factors for overall survival (OS). In the subgroup of patients with NMIBC, patients with clinically significant IPCa (csIPCa) had worse OS.

Conclusions: There were significant differences in IPCa detection rates between Chinese and Western populations. The main factors affecting survival were patient age and stage of BCa. However, in the NMIBC population, OS for patients with csIPCa appears poorer and further research is required.