Women undergoing hormone replacement therapy with both estrogen and progestin are at higher risk of developing breast cancer than those taking estrogen alone. Progestin, a synthetic version of the hormone progesterone, is taken in combination with estrogen by post-menopausal women because it reduces the risk of cancer of the uterus by inducing the monthly shedding of the uterine lining.

Hormone replacement therapy is commonly used by post-menopausal women to ward off osteoporosis and bone fractures, and symptoms of menopause such as vaginal dryness.

Risk Doubles With Combo -- Those who were using or had recently used the combination progestin-estrogen therapy had a 40 percent higher risk of developing breast cancer than women who did not take any hormones, the study found. The breast cancer risk was 20 percent higher among women who used estrogen alone compared to nonusers.

Assessing the comparative risk of estrogen alone versus estrogen-progestin was complicated by the fact that use of estrogen alone was associated with increased risk in lean but not heavy women. "We found differences between the two regimens among lean women but were unable to draw conclusions among heavier women,? wrote study author Catherine Schairer of the U.S. National Cancer Institute in Rockville, Maryland. The report said women?s risk of being diagnosed with breast cancer increased with each year of hormone treatment. The risk rose by 8 percent for each year of estrogen-progestin use, and by 1 percent for each year of estrogen use alone.

15-Year Study

The researchers examined 15 years of data on 46,355 women participating in a study on breast cancer screening, 2,082 of whom first developed the disease between 1980 and 1995. In an editorial accompanying the study, doctors from Harvard Medical School and Brigham and Women?s Hospital in Boston noted the findings reinforced previous evidence of breast cancer risk associated with recent use of hormone therapy for long periods. This has major implications for risk-benefit considerations because the risks of hip fracture and coronary heart disease ? primary targets of preventive use of hormone therapy ? do not become large until a decade or more after menopause..

The Journal of the American Medical Association January 26,2000;283:485-491, 534-535.

COMMENT: This 15 year study of nearly 50,000 women provides incredible insights as to just how dangerous progestins really are. Progestins are synthetic progesterone and they appear to increase the breast cancer risk 800% above that of using estrogen alone. I cannot think of one clinical situation where progestin (synthetic progesterone) are useful. The only reason they are being used is that the patent ran out on natural progesterone many decades ago. The ideal way to address hormone replacement therapy is to normalize the adrenal glands. This is best done by accurate salivary samples. Once the adrenal glands are normalized one can then consider the use of natural estrogen and progesterone if needed. My current favorite laboratory for this assessment is Bio Health Diagnostics 800-570-2000.

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