Outcomes of South Asian immigrant men undergoing transperineal prostate biopsy in an Australian setting.

Abstract

Introduction & Objectives: Incidence of prostate cancer (PCa) is traditionally considered low in South Asia. However, recent literature from North America and the UK suggests there is a significant increase in PCa incidence among South Asian upon immigration to Western countries, of up to 15-fold. This may simply be a function of differing rates of PSA screening in the West compared to South Asia. Some North American studies also report higher Gleason grade and higher stage at diagnosis in South Asian immigrants compared to the general population. This study aims to describe outcomes of South Asian immigrants undergoing transperineal prostate (TP) biopsy for elevated PSA in a private practice setting in Australia, who thereby have ready access to PSA screening. We aim to assess if there are differences in rates of positive biopsies, Gleason grade or tumour stage between South Asians and the general population. Method(s): Retrospective audit with ethics approval was conducted of 140 men (71 South Asian, 69 general population) who underwent TP biopsy in a private practice in Melbourne, Australia. 'South Asian' was defined as birthplace in SAARC countries. Datapoints included PSA level and density, biopsy results, cT stage, mpMRI and PSMA results, and treatment choice. Result(s): Regarding baseline statistics of South Asians and the general population, age was 61.5 and 64.8 years (P = 0.039), mean PSA 6.92 and 5.93 (P = 0.33), and mean PSA density 0.18 and 0.135 respectively (P = 0.089). For the outcome of positive TP biopsy for prostate cancer, multivariate logistic regression was performed with variables of birthplace, age, PSA, PSA density >0.15, and PIRADS score >3. South Asian origin was associated with OR of 0.43 (95% CI 0.19-0.94, P = 0.037) for positive TP biopsy as compared to the general population. PSA density >0.15 was also significant with OR 3.19 (95% CI 1.22-8.98, P = 0.021), while others did not reach significance - PSA level had OR 0.96 (95% CI 0.87-1.03, P = 0.3), age had OR 1.04 (95% CI 1.00-1.09, P = 0.073), and PIRADS score >3 had OR 1.57 (95% CI 0.71-3.52, P = 0.3). In those with PCa, there was no association with South Asian origin and ISUP grade (P = 0.2118) or T stage (P = 0.6002), via Wilcoxon rank sum test. Conclusion(s): In our cohort of men undergoing prostate biopsy for elevated PSA, whom are insured and have ready to PSA screening, South Asian origin was associated with a significantly lower odds of positive biopsy compared to the general population. This trend persisted after adjustment for PSA level, PSA density, age, and PIRADS score. This suggests that low rates of PCa incidence in South Asians may not purely be due to poor screening, as South Asian origin is a protective factor even in men with ready access to screening. Unlike North American data, in our cohort South Asian origin was not associated with differing ISUP grade or T stage.