Proportion of Gleason Score ≥8 Prostate Cancer on Biopsy and Tumor Aggressiveness in Matched Cohorts of East Asian and Non-East Asian Men

Abstract

Background: Historically, Asia had a lower prostate cancer (PCa) incidence and mortality compared with Western countries, but the gap is narrowing. Paradoxically, Asians have been reported to present with more advanced disease though more favorable outcomes. Despite PCa becoming an emerging health priority in East Asia, our knowledge remains limited. We compared the prevalence of high-grade PCa on biopsy and disease progression after radical prostatectomy (RP) in East Asian men from Asia and non-East Asian men from Western countries.

Methods: This retrospective cohort study included men who underwent prostate biopsy and RP at academic centers in Shanghai, China, and Toronto, Canada (2014-2019). The expanded RP cohort included East Asian men from Singapore (n=282) and non-East Asians from Paris (n=192). Primary endpoints included the proportion of men with Gleason score (GS) ≥8 on biopsy and metastasis-free survival (MFS) after RP for GS ≥8. Multivariable logistic regression and Cox proportional hazard models were performed. Propensity score matching was used to reduce imbalances between cohorts.

Results: PCa was found on biopsy in 2,343 of 4,905 (48%) East Asians and 2,317 of 3,482 (67%) non-East Asians (P<.001). Prostate-specific antigen (PSA) levels at presentation and the proportion of men with GS ≥8 were higher in East Asians than non-East Asians (12.4 vs 6.6 ng/mL and 15.0% vs 8.8%, respectively; both P<.001). On multivariable analysis, there was no difference in the proportion of men with GS ≥8 between matched cohorts with PSA <20 ng/mL (n=3,572; odds ratio, 1.05 [95% CI, 0.77-1.43]; P=.76). No difference in MFS was found after RP between matched cohorts (hazard ratio, 0.97 [95% CI, 0.55-1.70]; P=.92).

Conclusions: This contemporary study demonstrates that East Asian men are equally as likely to harbor aggressive PCa on biopsy as non-East Asian men at PSA levels observed in screening programs, with no difference in disease aggressiveness after RP. The assumption that unfavorable PCa at diagnosis is more common but less aggressive in East Asians should be revisited and viewed in the context of the expected increase in the PCa burden worldwide.