promise of prostate cancer research

Source: National Cancer Institute

Doctors all over the country are conducting many types of clinical trials (research studies) in which people take part voluntarily. These include studies of ways to prevent, detect, diagnose, and treat prostate cancer; studies of the psychological effects of the disease; and studies of ways to improve comfort and quality of life. Research already has led to advances in these areas, and researchers continue to search for more effective approaches.

People who take part in clinical trials have the first chance to benefit from new approaches. They also make important contributions to medical science. Although clinical trials may pose some risks, researchers take very careful steps to protect people who take part.

A man who is interested in being part of a clinical trial should talk with his doctor. He may want to read Taking Part in Clinical Trials: What Cancer Patients Need To Know and Taking Part in Clinical Trials: Cancer Prevention Studies. These NCI booklets describe how research studies are carried out and explain their possible benefits and risks. NCI's Web site at http://cancer.gov provides general information about clinical trials. It also offers detailed information about specific ongoing studies of prostate cancer by linking to PDQ®, a cancer information database developed by the NCI.

Causes of Prostate Cancer

Although researchers know several risk factors for prostate cancer, they still are not sure why one man develops the disease and another doesn't. (Known risk factors, which include aging, are listed in the "Prostate Cancer: Who's at Risk?" section.)

Some aspects of a man's lifestyle may affect his chances of developing prostate cancer. For example, some evidence suggests a link between diet and this disease. These studies show that prostate cancer is more common in populations that consume a high-fat diet (particularly animal fat), and in populations that have diets lacking certain nutrients. Although it is not known whether a diet low in fat will prevent prostate cancer, a low-fat diet may have many other health benefits.

Some research suggests that high levels of testosterone may increase a man's risk of prostate cancer. The difference between racial groups in prostate cancer risk could be related to high testosterone levels, but it also could result from diet or other lifestyle factors.

Researchers also are looking for changes in genes that may increase the risk for developing prostate cancer. They are studying the genes of men who were diagnosed with prostate cancer at a relatively young age (less than 55 years old) and the genes of families who have several members with the disease. Much more work is needed, however, before scientists can say exactly how changes in these genes are related to prostate cancer. Men with a family history of prostate cancer who are concerned about an inherited risk for this disease should talk with their doctor. The doctor may suggest seeing a health professional trained in genetics.

Prevention of Prostate Cancer

Several studies are under way to explore how prostate cancer might be prevented. These include the use of dietary supplements, such as vitamin E and selenium. In addition, recent studies suggest that a diet that regularly includes tomato-based foods may help protect men from prostate cancer.

The drug finasteride is being studied in the Prostate Cancer Prevention Trial, which involves thousands of men across the country who are participating for 7 years, until 2004.

Scientists are also looking at ways to prevent recurrence among men who have been treated for prostate cancer. These approaches involve the use of drugs such as finasteride, flutamide, and LH-RH agonists. Studies have shown that hormonal therapy after radiation therapy or after radical prostatectomy can benefit certain men whose cancer has spread to nearby tissues.

Researchers also are investigating whether diets that are low in fat and high in soy, fruits, vegetables, and other food products might prevent a recurrence. The Cancer Information Service can provide information about these studies.

Screening/Early Detection of Prostate Cancer

Researchers are studying ways to screen men for prostate cancer (check for the disease in men who have no symptoms). At this time, it is not known whether screening for prostate cancer actually saves lives, even if the disease is found at an earlier stage. The NCI-supported Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial is designed to show whether certain detection tests can reduce the number of deaths from these cancers. This trial is looking at the usefulness of prostate cancer screening by performing a digital rectal exam and checking the PSA level in the blood in men ages 55 to 74. The results of this trial may change the way men are screened for prostate cancer. The Cancer Information Service can provide information about this trial.

Treatment of Prostate Cancer

Through research, doctors try to find new, more effective ways to treat prostate cancer. Many studies of new approaches for men with prostate cancer are under way. When laboratory research shows that a new treatment method has promise, cancer patients receive the new approach in treatment clinical trials. These studies are designed to answer important questions and to find out whether the new approach is safe and effective. Often, clinical trials compare a new treatment with a standard approach.

Cryosurgery is under study as an alternative to surgery and radiation therapy. The doctor tries to avoid damaging healthy tissue by placing an instrument known as a cryoprobe in direct contact with the tumor to freeze it. The extreme cold destroys the cancer cells.

Doctors are studying new ways of using radiation therapy and hormonal therapy. They also are testing the effectiveness of chemotherapy and biological therapy for men whose cancer does not respond or stops responding to hormonal therapy. In addition, scientists are exploring new treatment schedules and new ways of combining various types of treatment. For example, they are studying the usefulness of hormonal therapy before primary therapy (surgery or radiation) to shrink the tumor.

For men with early stage prostate cancer, researchers also are comparing treatment with watchful waiting. The results of this work will help doctors know whether to treat early stage prostate cancer immediately or only later on, if symptoms occur or worsen.

Source

http://cancer.gov
NCI's Web site contains comprehensive information about cancer causes and prevention, screening and diagnosis, treatment and survivorship; clinical trials; statistics; funding, training, and employment opportunities; and the Institute and its programs.

See the complete index of What You Need To Know About™ Cancer publications.

Posted January 2004
Updated 8/01/2005