Abstract: PD47-06
Sources of Funding: This study was supported by GlaxoSmithKline (GSK).

Introduction

Global prostate cancer incidence rates are lower in Asian men than white men. To what degree this relates to less aggressive screening in Asian men or inherent differences by race remains to be determined. Our aim was to determine whether Asian race was associated with lower prostate cancer diagnosis in a study of all men who received prostate-specific antigen (PSA) screening and systematic prostate biopsies independent of PSA levels.

Methods

REDUCE was a 4-year, multicenter, randomized, double-blind, placebo-controlled study that followed biopsy-negative men with protocol-dictated PSA-independent biopsies at 2- and 4-years. Eligible men were aged 50-75 years, had serum PSA between 2.5-10 ng/mL, and a prior negative prostate biopsy. We tested the association between race and receipt of prostate biopsy as well as race and prostate cancer diagnosis using multivariable logistic regression.

Results

Of 8,122 men in REDUCE, 7,296 were of white or Asian race and had complete data for analysis. Asian men had lower BMI (24.8 vs 26.9, p<0.001) and smaller prostate volumes (34.2 vs 43.4 cc, p<0.001) but were similar in baseline age, PSA, family history of prostate cancer, and digital rectal exam findings compared to white men. There was no difference in rate of receiving a prostate biopsy between Asian and white men (p=0.634). After adjusting for various clinical and demographic characteristics, Asian men were less likely to be diagnosed with cancer during the 4-year study compared to white men (OR 0.56, p=0.011). When testing for differences in cancer grade, Asian race was significantly associated with decreased risk of low-grade cancer compared to white race (OR 0.43, p=0.016). This risk reduction was also observed for high-grade cancer (OR 0.63, p=0.290) though the association was not statistically significant.

Conclusions

Among men with a negative pre-study biopsy who all underwent biopsies largely independent of PSA, Asian race was associated with reduced risk of prostate cancer diagnosis. These data suggest less screening among Asian men globally cannot completely explain the lower risk of prostate cancer among Asian men. Further studies are needed to explore the inherent differences attributed by race in prostate cancer diagnosis.

Funding

This study was supported by GlaxoSmithKline (GSK).