TUESDAY, Sept. 28, 2004 (HealthDayNews) -- New research shows that a set of simple questions may help primary-care practitioners identify which women would benefit from a more elaborate discussion of tamoxifen, a drug that can help prevent breast cancer.
While tamoxifen is a standard of care to prevent breast cancer recurrences in women who have already had the disease, many professionals feel it is underused in helping prevent cancer in high-risk women who have not yet been diagnosed.
But a national trial showed that individuals at high risk for breast cancer who took tamoxifen had a 49 percent reduction in the incidence of breast cancer. The drug, however, can also have powerful and undesirable side effects, including blood clots, stroke and uterine cancer.
"We do have something we can give people, but we need a way to allow us to identify the right people," said Dr. John T. Cole, a medical oncologist with the Ochsner Clinic Foundation in New Orleans. "In a primary-care setting, a questionnaire could help discussion."
"Several studies show that tamoxifen can reduce the risk of getting breast cancer by up to 50 percent," added Dr. Russell Harris, a co-author of the new study, which appears in the Sept. 27 issue of the Archives of Internal Medicine, and an associate professor of medicine at the University of North Carolina. "The trouble is it has side effects, so we're trying to weigh the good against the bad. We tried to figure out in a regular practice how many women would fit into the category of good chances of benefits without big problems."
Between Jan. 15 and May 30, 2000, research assistants interviewed 605 women aged 40 to 69 in the waiting rooms of 10 general internal medicine practices in four cities in North Carolina. The women were asked to complete a five-to-10-minute anonymous, self-administered questionnaire designed to calculate their risk of breast cancer. The risk employs a model that takes into account seven risk factors, including number of first-degree relatives with breast cancer, age, and number of breast biopsies. Women with an estimated five-year breast cancer risk of at least 1.66 percent are considered to have a heightened risk.
The questionnaire also assessed whether a woman was at increased risk for developing one of tamoxifen's side effects. Women with a history of blood clotting, hypertension or diabetes were considered at high risk and were excluded. While a history of blood clots is universally considered to be a reason to exclude women, diabetes and high blood pressure have not been tested in this regard, said Dr. Larry D. Wagman, chairman of the division of surgery at City of Hope Cancer Center in Duarte, Calif.
In this study, 9 percent of white women in their 40s, 24 percent of these women in their 50s, and 53.4 percent of those in their 60s had a five-year estimated breast cancer risk of 1.66 percent or higher. Among black women, 2.9 percent of those in their 40s, 7.1 percent of those in their 50s, and 13 percent of those in their 60s had a similar risk. When the possible side effects were factored in, 10 percent or fewer of the women were good candidates for further discussion of tamoxifen.
The results of the study apply primarily to white women, however, as there were not enough black women in the study to generate strong conclusions.
The study authors went on to figure out that if all eligible women took tamoxifen for five years, 6 percent to 8.3 percent of all breast cancers in women aged 40 to 69 would be prevented. This equates to nine to 15 cases per 10,000 women.
"It's only a small number of women, but some ought to consider it," Harris said. "And researchers should realize that if you have a better tamoxifen, you might be able to offer it to more women."
"The interviewing of women is not done to the extent it should be," Wagman added. "This paper says it's pretty easy and pretty quick. One thing is family history and the other is a history of biopsies. You might be able to ask two questions, then figure out if you need to delve further. Anything that makes it easier for busy family practitioners to ask the right question is a good thing. It's a question of physician empowerment and ease of action."
More information
Visit the U.S. National Cancer Institute for more on tamoxifen.
