|LE Magazine August 2000 |
Hormone Replacement and Heightened Cancer Risk
In The News
A NEW PIECE OF THE PUZZLE ABOUT the adverse effects of hormone replacement therapy has emerged from a recent mainstream scientific study. Use of the synthetic estrogen/progestin drug combination can more than double the risk of a certain type of breast cancer in menopausal women, according to a study completed recently at the Fred Hutchinson Cancer Research Center, in Seattle, Washington.
This is the latest in a series of studies to connect estrogen and progestin to a heightened risk of cancer. As one bit of damning evidence after another has emerged, even mainstream, establishment researchers have begun to question the advisability of this astonishingly widespread treatment.
The new findings, reported in the journal Cancer (88:2570-2577, 2000), pertain to a relatively rare form of breast cancer. But they indicated that, in those cases, the magnitude of hazard is substantial. Investigators focused on what is known as lobular breast cancer. This malignancy occurs in the milk-producing lobules of the breasts and accounts for 10% to 15% of all cases. About 85% of all breast cancer cases are of the ductal variety- occurring in the ducts that carry milk to the nipples.
"Our finding is only preliminary, but it is significant on several counts," lead researcher Christopher Li, M.D. told LIFE EXTENSION. "First, it establishes a danger of considerable significance."
Dr. Li and colleagues studied 537 women of at least 50 years of age in King County, Washington who had breast cancer between 1988 and 1990. Then, they compared them to 492 women who'd never had breast cancer. What they found was that women who had taken combined estrogen/progestin therapy for at least six months and for as long as four years had a 2.6-fold greater incidence of lobular cancer than the women who never took the hormones and who never had the disease.
"This study is the first to establish a relationship between lobular cancer and combined estrogen/progestin therapy," Dr. Li observed. These findings also elaborate upon an earlier study in which Dr. Li found that the incidence of lobular breast cancer rose an alarming 35% between 1988 and 1995.
Lobular breast cancer may be fairly uncommon, but the importance of the finding has broader implications. It suggests that a fairly extensive pattern of broad, generalized risk may be at work-and that is the second element of significance in Dr. Li's study.
"We don't want to jump to conclusions-much more research is necessary before we can make any definite statements or recommendations. But coming on top of other research, the finding suggests that we may be contemplating a far-reaching hazard," Dr. Li continued.
"It is quite well reported in the scientific literature that the estrogen/ progestin drug combined therapy entails well-defined risk of several types," added Dr. Li. Previous studies established a heightened danger of breast cancer, including ductal type, among users of combined HRT.
"Earlier this year, a study published in the Journal of the American Medical Association established a greater than two-fold increased risk of all breast cancers in people who used the estrogen/progestin drug combination for more than four years. And the reality is that it is quite common for people to use these hormones for at least that long-and much longer in many cases.
"Taken together, it all adds up," noted Dr. Li. "If you figure that one in eight women get breast cancer, and if 80% to 85% of those cases are of the ductal type, the increased risk of ductal breast cancer that comes from estrogen/progestin therapy could boost that one in eight incidence to one in five. This is something to consider carefully.
"It is only recently that we have come by these data indicating the potential dangers of combined HR1: The therapy itself came into use during the 1980s. Prior to that, people took estrogen alone. Estrogen, it turned out, increased the risk of uterine or endometrial cancer in women who had not had a hysterectomy. And there was some evidence that taking progestin in tandem with estrogen toned down that risk."
As an aside, other research indicates that progestin does not attenuate this increased danger of uterine cancer nearly as much as originally believed. While many clinicians and health activists suspected for years that combining estrogen and progestin was a bad idea, scientific confirmation of that intuitive position has only come to light in recent years.
"As with many other therapies, the downside of combined HRT emerged only after long-term use over many years," added Dr. Li. "It is way too early to recommend any specific action to people taking combined HRT: We have a lot more questions to answer before that can happen. And nobody should discontinue the therapy without careful consultation with a physician.
"But I always encourage people to talk to their doctors about the risks and benefits of any therapy, so they can understand that not all medical questions are cut and dried or black and white. People need to find out all they can about anything that affects their health, so they can make the best, most informed decision about what type of care, if any, they will elect to receive.
"One thing seems certain, however. Our studies, although preliminary, suggest that the incidence of lobular cancer is increasing nationwide, and that the use of post-menopausal hormone replacement therapy, specifically the use of combined synthetic estrogen plus progestin drug preparations, may be contributing to this increase."
Close to 9 million American women take the estrogen/progestin drug combination and another 12 million take estrogen alone for hot flashes, mood swings, vaginal dryness and other symptoms of menopause, as well as broken bones and other serious problems that relate to osteoporosis.
The standard medical rationale for using combined HRT also includes a reduction in heart disease mortality and a decrease in the incidence of Alzheimer's disease. But there is no solid, reliable evidence that either case is true. On the whole, then, 'the word to the wise about estrogen and progestin drugs is caution. -James O'Brien