Environmental Factors

There is some descriptive data which points to a role for environmental factors, such as diet, in the development of prostate cancer. For example, some believe that diets high in animal fats and milk products may be associated with a higher prostate cancer risk; it has also been suggested that lycopene (a compound found in tomatoes and tomato products), selenium , and vitamin E in the diet may provide some protection against prostate cancer. There has not yet been sufficient research to prove or disprove these claims.

It has also been proposed that obesity, diabetes, tobacco smoking, alcohol consumption, occupational exposures, sexually transmitted diseases, vasectomy and physical activity may play a role in prostate cancer development (either protective or harmful), but at present there is a lack of consistent evidence to support any of these factors .

There is currently research being conducted to try to fill some of these knowledge gaps and brief descriptions of some of the larger studies have been provided below:

- The European Prospective Investigation into Cancer and Nutrition (EPIC) is a major European trial. It is looking at the relationship between diet, nutritional status, lifestyle and environmental factors, and cancer incidence (including prostate cancer). Over half a million patients from ten European countries have been recruited on to this long-running trial, and results are being published throughout its duration.

-The Selenium and Vitamin E Chemoprevention Trial (SELECT) is another major trial currently running in the US and Canada. It is looking at the role of selenium and vitamin E in prostate cancer prevention. Vitamin E and Selenium are anti-oxidants (substances believed to counteract the harmful affects of oxidation on the human tissue). Results from this trial are expected to be published in a few years.

- The US National Cancer Institute is currently coordinating the BCP3 study, an association of six large cohorts (including the European EPIC study) which are investigating the role of gene-environment interactions on cancer development. Launched in 2003 this study will combine results from all six cohorts. It aims to identify gene alterations which are associated with prostate cancer development; and investigate the relationship between these alterations and lifestyle factors; it will also investigate the relationship between gene alterations and several hormones which have been associated with prostate cancer development (see below).