1. ¹Department of Urologic Surgery, University of Kansas Medical Center, Kansas City, KS, USA
2. ²Department of Hematology/Oncology, University of Kansas Medical Center, Kansas City, KS, USA
3. ³Kansas City Veterans Administration Medical Center, Kansas City, MO, USA

Correspondence: Dr JB Thrasher, Department of Urologic Surgery, University of Kansas Medical Center, 3901 Rainbow Blvd, Mail Stop 3016, Kansas City, KS 66160, USA. E-mail: bthrasher@kumc.edu

Received 19 October 2006; Revised 12 November 2006; Accepted 28 December 2006; Published online 20 February 2007.

Abstract

Worldwide disparities exist between geographic regions with regard to prostate cancer incidence and mortality. Countries in East Asia have lower rates of prostate cancer compared with Western countries such as Canada and the US. Some suggest that dietary differences between the two geographic regions, particularly the higher amount of phytoestrogens consumed in East Asia, is responsible for the difference in prostate cancer incidence. The mechanism of action of the soy isoflavones is incompletely understood, but in regards to prostate carcinogenesis likely involves estrogenic effects, cell cycle inhibition, anti-angiogenesis and induction of apoptosis. Recent clinical studies have provided mixed results with regard to a clear association between prostate cancer and soy consumption. Further studies are needed to understand more clearly the relationship between soy consumption and prostatic diseases.