OHSU Cancer Institute Study Looks At Whether Fish Oil, Green Tea Reduce Prostate Cancer Risk

02/24/11  Portland, Ore.

Oregon Health & Science University Cancer Institute researchers want to know whether fish oil or green tea slow the growth of prostate cancer cells.

Jackilen Shannon, Ph.D., M.P.H.,is looking for men whose physicians have recommended a repeat prostate biopsy. These men have not been diagnosed with cancer, but their first biopsy has raised concerns and they are considered at a high risk for the cancer.

“We hope to find a noninvasive way to reduce their risk of developing prostate cancer or to at least slow the growth of this cancer. This study focuses on a group of men who have had no other avenue of help offered to them, except to keep having biopsies,” said Shannon.

Bruce Thom, 56, of Portland participated in the study from January through March 2007. He knew he could be at risk because his father had prostate cancer.

“My doctor suggested the opportunity when he determined that I needed a repeat biopsy for an enlarged prostate. I had undergone two biopsies previously and felt the study added some value to the pain and stress of the procedure. It represented a chance for me to help someone else later on with some preventive options,” Thom said.

“Prostate cancer is the most common cancer in men, with a sharp increase in cancer cases seen in elderly men. Understanding the processes that control this transformation is key to improving patient outcomes,” said Mark Garzotto, M.D., associate professor of urology, OHSU School of Medicine, member of the OHSU Cancer Institute, and director of urologic oncology at the Portland Veterans Affairs Medical Center.

In prostate cancer there is evidence of an overabundance of fatty acid synthase, a protein involved in making new, free fatty acids. These free fatty acids are then available for use in making new cancer cells, called cell proliferation. Usually the body regulates the amount of fatty acid synthase. But the cancer cells seem to block that regulation. However, it is thought that fish oil or the green tea may be able to tell the cancer cells to stop making fatty acid synthase.

“This is an exciting study because men who are at high risk for prostate cancer desperately want to know what they can do to help reduce this risk. This study promises to give us some answers,” said Tomasz M. Beer, M.D., director of prostate cancer research and Grover C. Bagby Chair for Prostate Cancer Research at the OHSU Cancer Institute.

Cancer is a complex disease that develops when cells lose the ability to control their rates of growth and at the same time do not die when they should. Cell death is called apoptosis. During the past few years, it has become evident from laboratory experiments that certain fatty acids play a key role in regulating genes involved in the control of cell proliferation and apoptosis, and hence tumor cell growth, explained Shannon.

“However, there has been little work to show whether this also happens in human beings, and if so, whether we can change the rate of cancer growth by simply giving someone a dietary supplement,” Shannon said.

The double-blind, placebo-controlled study hopes to enroll 144 men during a three month time period. Double-blind means that neither the researchers nor the men know whether they are taking the specially formulated, high-dose fish oil and/or green tea pills or placebo pills. The amount of fish oil and green tea being used in this study is considered safe and has shown very few and minor side effects, such as burping or gas.

The clinical trial is funded through an $800,000 grant from the Department of Defense prostate program and the National Institutes of Health.

Men, 21 and older, who have been referred for a repeat biopsy and who are interested in learning more about the study, can call 503 494-7419.

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Particulars: Shannon is also an assistant professor of public health and preventive medicine, and endocrinology, OHSU School of Medicine; a scientist in the OHSU Center for Research on Occupational and Environmental Toxicology; and a member of the Portland Veterans Affairs Medical Center.

Beer, is also an associate professor of medicine, (hematology/medical oncology, OHSU School of Medicine.

The OHSU Cancer Institute is the only cancer center designated by the National Cancer Institute between Sacramento and Seattle. It comprises some 120 clinical researchers, basic scientists and population scientists who work together to translate scientific discoveries into longer and better lives for Oregon's cancer patients. In the lab, basic scientists examine cancer cells and normal cells to uncover molecular abnormalities that cause the disease. This basic science informs more than 200 clinical trials conducted at the OHSU Cancer Institute.