Question: What influence does lifestyle play in the chances of developing prostate cancer?
Answer: We think that lifestyle has a very important effect on your risk of getting prostate cancer. The foods that you eat, your level of physical activity, your weight, and maybe even drugs that you take all have an effect on your risk. We've seen that studies seem to show that men with diets that are high in fat, high in red meat, and high in dairy foods seem to increase the risk of developing advanced prostate cancer.
Now one thing that's been interesting, since we've started testing for prostate cancer with PSA (prostate-specific antigen), we often find very, very early cancers that would not have been detected before we had the PSA test available. So when we look at associations with things like diet, if we look at all cancers, sometimes the associations are not found. But when we look at advanced cancers, those are the ones where risk seems to increase with diet. And we think the reason for that is that all men have a very strong propensity to develop some cancer in their prostate by the time they reach 70 or 80.
For example, if you look at men who have died from other causes at age 80, about 70 percent of them will have some prostate cancer that they never knew they had in their prostate. And we think some of the factors that maybe the difference between those men who had prostate cancer and never had a problem with it from the men who have prostate cancer that needs to be treated, may have to do with exposures that are related to lifestyle such as diet.
Other things that are associated with diet that seem to be important are your level of physical activity. For example, if you take in a lot of calories from your diet but you don't exercise, you don't have a lot of physical activity, you're going to tend to gain weight. And overweight seems to be a risk factor for prostate cancer. We don't know if it is your weight itself or if it's the balance between the calories that you take in and the calories you expend and the metabolic effects of that process that affect your risk of prostate cancer. But we see that men who are overweight or men who are obese have an increased risk of developing advanced prostate cancer.
Some common drugs, such as aspirin, and other anti-inflammatory drugs, so called NSAIDs, also seem to lower your risk of advanced prostate cancer by about 30 percent. There's some interesting data coming out from studies of drugs called statins that are used to lower cholesterol. And those also seem to lower your risk of advanced prostate cancer by about 30 percent. We think that the link between these drugs and prostate cancer has to do with inflammation which we think plays an important role in prostate cancer risk.