Scripps to Help Study Disputed Cancer Drug : Medicine: Tamoxifen will be given to healthy women at risk of breast cancer. Critics say more study is needed before a national test is conducted.
Scripps Memorial Hospital will participate in a controversial national trial of a drug that doctors hope will prevent breast cancer in healthy women who are at risk, officials announced Tuesday.
Some doctors believe it is medical folly to experiment with healthy women, especially since there are still unanswered questions about side effects of the drug, a synthetic hormone called tamoxifen. It’s one thing for a woman who might be facing death to take this drug, they say, and quite another for a healthy woman to take it.
Supporters of the trial counter that tamoxifen is a woman’s only chance--besides surgically removing her breasts--of preventing breast cancer. Furthermore, they say, for these women, the chances of getting breast cancer are high--while the probability of side effects is low.
Doctors agree that tamoxifen has proven its effectiveness in extending the lives of women who get breast cancer, as well as preventing new cancers from growing. The anti-estrogen drug is widely used in post-surgical cancer therapy for women considered at risk for recurrence.
The disagreement centers on how much doctors should know about a drug before administering it to thousands of healthy women.
“I don’t see any hurry in doing a very large study on healthy women,” said Dr. Diana Petitti, an epidemiologist with the University of San Francisco. “By waiting one or two years and doing more work on the effects of tamoxifen, I’d feel better about putting thousands of healthy women on the drug.”
The National Women’s Health Network, an advocacy group, also opposes the trials.
Women might be trading some breast-cancer risk for other health problems, said Cindy Pearson, the group’s program director.
“Is that prevention?” she said.
But a number of doctors disagree, saying the drug offers more benefits than risks. It also offers beneficial side effects of reducing cholesterol and easing cardiovascular problems, they say.
“Breast cancer has been called an epidemic, and, to the extent that we can stem the epidemic, it’s a major step forward,” said Dr. Richard Anderson, a medical oncologist at Scripps.
Anderson likened the dispute over tamoxifen to the fuss initially made over medications for high blood pressure, which eventually clearly showed a dramatic decrease in incidence of stroke and heart disease. Anderson believes the benefits of tamoxifen, like blood pressure medications, will markedly outweigh its potential risks.
“The promise of the drug is that it will allow a woman to be pro-active in dealing with a potential threat to her life,” Anderson said. “This is preventive medicine. Preventive medicine is the very best kind. In that sense, this is very promising.
“No one is saying that every woman should take tamoxifen. This is experimental, and I think it’s a worthy experiment. The fact that it’s experimental means we don’t know all the answers.”
Starting this spring, Scripps Memorial Hospital in La Jolla will join scores of other facilities across the nation in participating in a National Cancer Institute study. During a five-year study of 16,000 women who have a family history of breast cancer, half the women will receive sugar pills and the other half will get tamoxifen.
Critics of the trial cite an increased risk of cancer of the lining of the uterus, blood clots and the potential for early menopause. Still others say too little is known about how the drug affects the lipids. Although doctors know it does have a beneficial effect of lowering one type of lipoprotein called low-density proteins or LDL, they are not certain how it affects the “good” type of cholesterol, or high-density lipoprotein, HDL.
The drug also causes liver cancer in rats--a trend that has not been seen among humans, said Dr. Susan Nayfield, a program director with the National Cancer Institute’s division of cancer prevention and control. She also counters that the other ill effects--endometrial cancer and early menopause--are experienced by only a fraction of those who take the drug.
“There is some controversy about the trial. But our experience has been that much of the controversy exists because of a lack of information about tamoxifen,” Nayfield said. “I believe the drug is safe.”
Tamoxifen acts like estrogen. In fact, it fools the estrogen receptor cells--areas on the surface of the cells to which the hormone adheres. Because the drug attaches to the receptors, it blocks the effects of estrogen, which is believed to play a role in causing tumor growth.
In the United States, about 175,000 women will be diagnosed with breast cancer this year. With 44,500 women expected to die this year from the disease, breast cancer is the most common malignancy among women. In California, 4,200 women died last year of breast cancer. Against this dismal backdrop, tamoxifen offers a woman at risk the prospect of flouting the potentially deadly disease.
“Here is a group of people saying maybe we can prevent breast cancer before it starts,” said Dr. Sol Gusberg, a past president of the American Cancer Society and a professor of gynecology at Mt. Sinai School of Medicine.
Would Gusberg advise his high-risk patients to enroll in the trial?
“I’d wait until there is data,” he said.
