In 1990, prostate cancer surpassed lung cancer as the most common noncutaneous malignancy diagnosed in men in the US This year prostate cancer will be responsible for over 31,000 deaths in this country, resulting in an annual loss of almost 300,000 years of life. The incidence of prostate cancer shows strong age, race, and geographical dependence. Less than 1% of cases are diagnosed under the age of 40, although this may represent an underestimate as screening for disease in young men is rare. Prostate cancer is relatively uncommon in Asian populations and prevalent in Scandinavian countries, and the highest incidence (and mortality) rates known are in African Americans, being~ 2-fold higher than in Caucasian Americans (Figure 1). Mortality rates vary significantly by country, ranging from over 32 per 100,000 in Trinidad, to 23 per 100,000 for Caucasians in the US, to 4 per 100,000 in Japan (Boring et al., 1992).

Like most common cancers, the etiologic factors associated with prostate cancer are varied, encompassing both host genetic and environmental influences. Environmental factors are clearly indicated by migration studies; eg, large increases in risk in Japanese men occur when they move to the United States. Etiologic factors include aging, familial clustering, race, hormonal influences, diet (both inductive and preventive factors), and lifestyle factors (Hsing and Devesa, 2001). Age, familial clustering, and race are clearly important, well-documented risk factors, and dietary influences such as red meat, high fat (elevated risk), antioxidants (eg, selenium, lycopene [lowered risk]), and hormone levels are most likely critical factors as well. The finding of increased risk associated with increased serum levels of insulin-like growth factor 1 (IGF-1)(Chan et al., 1998) is an example clearly implicating nonandrogenic growth regulatory pathways as potentially important in determining prostate cancer risk.