Prevalence of prostate cancer across the globe: what can autopsy studies teach us about this peculiar disease?

Prostate cancer (PCa) represents a major public health burden in the western world. It is a peculiar disease as more men die with it than from it. Also interestingly, PCa was virtually unknown for centuries until the 20th century. Randomized trials on PCa screening have outlined the risks of over-diagnosis and over-treatment of latent cancers. Significant geographical differences in PCa incidence and mortality exist, being supposedly low among Asian men compared to Caucasians. In some areas like Korea and Japan, changes have been observed that cannot be explained easily by changing diagnostic procedures and increases in mortality may be due to lifestyles and dietary changes. We have recently studied and compared the prevalence of PCa in Caucasian (CAU) from Moscow, Russia and Asian (ASI) men from Tokyo, Japan. We chose a specific Cau population in Russia with little sun exposure and high fat diet but without widespread PSA screening. Autopsy data in western countries (North America and Europe) would have been heavily contaminated due to opportunistic PSA screening. Screening in Asi men in Japan is uncommon. Prostates were removed en-block with the seminal vesicles within 24 hours of death and analyzed in toto (perpendicular sections at 4 mm intervals) by an experienced uro-pathologist in Toronto. PCa was found on autopsy in a similar proportion of Russian Caucasian and Japanese men. Over 50% of cancers are Gleason ≥7 in Japanese and nearly 25% in Russian Caucasian men raising questions about 1) previous assumptions related to Asian PCa and 2) the notion of significant vs. insignificant cancers. Autopsy studies are key to improve our understanding of this very curious cancer.