In a study of 40 women at high risk for breast cancer, six months of treatment with Celebrex lowered levels of estrogen receptors — a marker of cell reproduction that can signal cancer, says Banu Arun, MD, an associate professor in the department of breast medical oncology at the University of Texas M.D. Anderson Cancer Center in Houston.
"This is a preliminary but exciting finding that has not been reported in human studies before," she says.
The development of breast cancer is a multi-step process, Arun tells WebMD. Even before there is formation of breast cancer cells, regular breast cells start to reproduce while simultaneously accumulating abnormal proteins.
Celebrex appears to disrupt the process at this early step, she says, thus making it an ideal candidate for prevention.
Currently, tamoxifen is the only drug approved for the prevention of breast cancer in women at high risk of the disease due to family history, faulty genes, or other factors. But tamoxifen carries a risk of side effects, including uterine cancer.
As a result, cancer doctors have been searching for a safer, better drug, Arun says. And animal and lab studies suggested that Celebrex stalls the formation, growth, and spread of new cancer cells.
A member of a class of drugs known as Cox-2 inhibitors, Celebrex works by targeting the Cox-2 enzyme that plays a major role in arthritis and inflammation. Celebrex is also used to prevent precancerous growths in people with a rare form of inherited colon cancer, familial adenomatous polyposis. And previous studies have shown that Celebrex may also help fight prostate cancer.
Celebrex May Aid In Breast Cancer Prevention
The goal of the new study was to see if Celebrex could reduce markers of cell reproduction in women at high risk of breast cancer, Arun says. "That is, could Celebrex be a potential breast cancer prevention drug with fewer side effects [than tamoxifen]?"
At the start of the study, which was presented at the annual San Antonio Breast Cancer Symposium, doctors used a thin needle to collect breast cells from each of the women. Levels of estrogen receptors and other markers of cell reproduction were measured.
The women were given Celebrex for six months and the procedure was repeated. The upshot: Estrogen receptors were significantly reduced, from 30 percent to 20 percent, Arun says.
She says she is continuing the study to examine the impact of Celebrex on other markers of reproduction in breast cells.
William Gradishar, MD, a breast cancer specialist at Northwestern University in Chicago and a spokesman for the American Society of Clinical Oncology, says the use of Celebrex for breast cancer prevention is "a reasonable strategy based on the underlying biology of the disease."
While the work is preliminary, it offers proof of principle, he tells WebMD.
Other Cox-2 inhibitors include Bextra and Vioxx. Vioxx was removed from the market in September because of an increased risk of heart attacks and strokes; this week, a warning was added to Bextra's label saying it should not be used in people undergoing heart bypass surgery due to an increase in heart problems and blood clots.
While more research is being done on Celebrex, a study earlier this week showed that Celebrex does not seem to carry the same heart attack risk as Vioxx.
Sources: San Antonio Breast Cancer Symposium, San Antonio, Dec. 8-11, 2004. Banu Arun, MD, associate professor, department of breast medical oncology, University of Texas M.D. Anderson Cancer Center, Houston. William Gradishar, MD, professor of medicine, Northwestern University, Chicago; spokesman, American Society of Clinical Oncology.
By Charlene Laino
Reviewed by Michael W. Smith, MD
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