JEDDAH, 16 September — The results of two new American studies dealing with the effects of Hormone Replacement Therapy (HRT) on post-menopausal women over long periods of time have renewed the discussion concerning HRT. Researchers from the National Cancer Institute have found that a large number of women using estrogen replacement therapy after menopause are at increased risk of ovarian cancer. Their report was published in the July 17, 2002, issue of JAMA (Journal of the American Medical Association). The risk increased with longer periods of estrogen use.
Estrogen is a natural hormone produced in the ovaries. After menopause, the ovaries produce lower levels of both estrogen and another hormone, progesterone. When natural menopause is complete — usually between 45 and 55 — hormone output decreases significantly. In the 1940s, women began using estrogen to counteract some of the discomforts of menopause. Dr. Nadia Ghannam, Consultant Endocrinologist, said that doctors also gave estrogen to post-menopausal women with low bone mass to protect their bones. In the 1970s, however, it became clear that women who took estrogen had a much greater risk of developing endometrial cancer (cancer of the lining of the uterus). Doctors then began prescribing progestin, a synthetic form of progesterone, with much lower doses of estrogen. The addition of progestin to estrogen therapy reduces the risk of cancer and as a result, it has become increasingly common.
In addition to studying the effects of using estrogen alone, the researchers looked at whether women using estrogen-progestin therapy were more likely to develop ovarian cancer and found no increased risk.
At the same time, the results of another study by Women’s Health Initiative (WHI), also published in the July 17 issue of JAMA, showed increases in breast cancer, coronary heart disease, stroke and blood clots among women who had been on estrogen-progestin therapy for an average of 5.2 years. On the other hand, studies have shown that HRT does lower the risk of osteoporosis.
The public health question asked in the WHI study was whether the hormones have benefits that exceed their risk. It studied the effects of one type of estrogen (Premarin) and one type of progestin (MPA). The WHI Data and Safety Monitoring Board reviewed the health status of women in the study and recommended that those taking estrogen plus progestin stop their dosage because the risks exceeded the benefits. As for women who had had a hysterectomy and were taking estrogen alone, they were allowed to continue because it is uncertain whether benefits outweigh risks. To date, the study has not shown an increased risk of breast cancer among these women.
"What this means is that women using HRT should be more careful but they should not panic," said Dr. Ghannam. "For women who have been using the hormone for 6 years or more, having an annual check-up of breast, uterus and ovaries is fine. But those who have been using it for less than 5 years, then find an alternative. Talk to your doctor about which one."
The matter of using hormones is a complex one with both risks and benefits. As one researcher explained, "because hormone therapy may influence so many conditions that affect women after menopause — cardiovascular problem, osteoporosis, breast cancer, uterine cancer, gallbladder disease, blood clots, and potentially ovarian cancer — we should no longer think of a woman basing her decision to use hormones on the potential risk of just one condition. Women should continue to talk to their health care providers about whether hormones are right for them."
Dr. Ghannam brought up another point: "Heredity also plays its part. For example, a woman whose mother or sister or aunt has had breast cancer is definitely at higher risk than someone whose family is free of the problem.
The risk becomes much greater if HRT is used. There are also a number of other factors to be considered — smoking, diabetes, hyperlipidemia, hypertension and low-calcium intake. These will all be involved in a decision for or against HRT."
