The Prostate Cancer Prevention Trial (PCPT) studied whether the drug finasteride can prevent prostate cancer in healthy men 55 years of age and older. This prevention study showed there were fewer prostate cancers in the group of men that took finasteride compared with the group of men that did not . Also, the men who took finasteride who did have prostate cancer had more aggressivetumors. The number of deaths from prostate cancer was the same in both groups. Men who took finasteride reported more side effects compared with the group of men that did not, including erectile dysfunction, loss of desire for sex, and enlarged breasts.
The Reduction by Dutasteride of Prostate Cancer Events Trial (REDUCE) studied whether the drug dutasteride can prevent prostate cancer in men aged 50 to 75 years at higher risk for the disease.This prevention study showed there were fewer prostate cancers in the group of men who took dutasteride compared with the group of men that did not. The number of less aggressive prostate cancers was lower, but the number of more aggressive prostate cancers was not. Men who took dutasteride reported more side effects than men who did not, including erectile dysfunction and loss of desire for sex.
The following have been proven not to affect the risk of prostate cancer, or their effects on prostate cancer risk are not known:
Selenium and vitamin E
The Selenium and Vitamin E Cancer Prevention Trial (SELECT) studied whether taking vitamin E and selenium (a mineral) will prevent prostate cancer. The selenium and vitamin E were taken separately or together by healthy men 55 years of age and older (50 years of age and older for African-American men). The study showed that selenium and vitamin E did not decrease the risk of prostate cancer.
It is not known if decreasing fat or increasing fruits and vegetables in the diet helps decrease the risk of prostate cancer or death from prostate cancer.
Regular use of multivitamins has not been proven to increase the risk of early or localized prostate cancer.
Some studies have shown that a diet high in lycopene may be linked to a decreased risk of prostate cancer, but other studies have not. It has not been proven that taking lycopene supplements decreases the risk of prostate cancer.
Cancer prevention clinical trials are used to study ways to prevent cancer.
Cancer prevention clinical trials are used to study ways to lower the risk of developing certain types of cancer. Some cancer prevention trials are conducted with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are conducted with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.
The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include eating fruits and vegetables, exercising, quitting smoking, or taking certain medicines, vitamins, minerals, or food supplements.
New ways to prevent prostate cancer are being studied in clinical trials.
Clinical trials are taking place in many parts of the country. Information about clinical trials can be found in the Clinical Trials section of the NCI Web site. Check for clinical trials in NCI's PDQ Cancer Clinical Trials Registry for prostate cancer prevention trials that are accepting patients.