Abstract
BACKGROUND: This study aims to investigate survival outcomes among individuals with high-risk, regional, and metastatic prostate cancer (PCa) by culturally and linguistically diverse (CALD) status in Victoria, Australia. METHODS: Individuals with high-risk, regional, and metastatic PCa (February 2009-February 2024) registered in the Victorian Prostate Cancer Outcomes Registry (PCOR-Vic), with last follow-up on 31 July 2024. CALD status was derived from study participants' country of birth and subgrouped into: mainly non-English-speaking countries (NESC) (CALD backgrounds), mainly English-speaking countries (MESC) outside Australia (MESC-born), and Australia (reference group). The primary outcomes, all-cause mortality (ACM) and PCa-specific mortality (PCSM), were determined through linkage of PCOR-Vic to Victorian Cancer Registry death data. ACM and PCa-specific survival were estimated using Kaplan-Meier curves and the cumulative incidence function. Weibull parametric survival and Fine-Gray competing-risks regression models, adjusted for sociodemographic and clinical variables, assessed the association of CALD status with ACM and PCSM. RESULTS: Of 10,024 eligible participants, 32% died. The median survival time (death) was 116 months, and median follow-up time (censoring) was 66 months. CALD individuals had lower 5-year overall survival compared to Australian-born individuals (66% vs. 71%). While unadjusted models suggested higher ACM among CALD individuals (adjusted hazard ratio [aHR] = 1.20, 95% confidence interval [CI] = 1.11-1.30), adjusted models showed lower ACM (aHR = 0.89, 95% CI = 0.82-0.97) and PCSM (adjusted subdistribution hazard [asHR] = 0.86, 95% CI = 0.76-0.96) than Australian-born individuals. There were significant (p-value < 0.05) interactions between CALD and age (older CALD individuals had higher hazard of ACM and PCSM) and CALD and PCa risk category (CALD individuals with regional PCa had higher hazard of ACM). CONCLUSIONS: While CALD individuals had lower overall survival and higher ACM than Australian-born individuals, CALD individuals exhibited lower ACM and PCSM following adjustments. Interactions of age and PCa risk category with CALD influenced mortality. Contributing factors (e.g., late diagnosis) should be addressed to reduce disparities by CALD status.