a new compound would help women avoid the risk of developing breast cancer after hormone replacement therapy ( hrt ). T M Wilson and his colleagues at the Duke University Medical Centre, Durham, North Carolina, usa and Glaxo Wellcome, claim that the compound called gw 5638 could become an important medicine for women as a first-line treatment for the breast cancer. It can also work as an all purpose oestrogen replacement pill that protects against the heart disease and osteoporosis without increasing the risk of cancer. The non-steroidal compound is a kind of synthetic oestrogen ( Endocrinology , Vol 138, No 9).
When oestrogen levels drop at menopause, women experience extreme distress with symptoms such as vaginal dryness, sleep disturbances, depression and other mood disorders. They receive contradictory advice from doctors about the use of hormones.Even most of the gynaecologists advocating hrt do not have proper knowledge of the benefits and risks of the therapy.
At present, data available on this aspect are not sufficient to provide a clue about the effect of hrt. However, long-term trials are being conducted to study the impact of the therapy. One of the largest such studies is being conducted with the help of the National Institutes of Health, Bethesda, usa. Results of this long-term study with over 275,000 women in the age group 50-79 years - half on hrt and the rest on placebo -are expected to be available by the year 2007.
One of the compelling reasons why most women take hrt could be its impact on their personality. It makes them look much younger and healthier. Last year, an analysis at the New England Medical Center, Boston, usa , demonstrated that for most women, hrt is more likely to extend life span than shorten it, provided they do not have heart disease, hip fractures and close relatives with breast cancer. In post-menopausal women, oestrogen cuts the risk of Alzheimer's disease by half and strengthens the bones in all part of the body including teeth.
But there are some negative implications of the therapy. The collaborative group on hormonal factors in breast cancer has found that the risk of having breast cancer increases in women who undergo hrt. They reached the conclusion after analysing 51 studies from 21 countries with nearly 160,000 women ( The Lancet , Vol 350, No 9084).
The chances of dying of breast cancer are greater in those women who undergo oestrogen therapy for a longer period. Oestrogen intake also increases the risk of gall bladder cancer and when taken with progesterone, it further adds to the risk of uterine cancer. In the absence of female hormones, older women lose calcium from the body. It makes them more vulnerable to osteoporosis and associated problems of fracture of hips.
Scientists are testing the compound gw 5638 in women who have failed to get benefit of standard breast cancer drug called tamoxifen. The drug blocks oestrogen's cancer promoting properties in breast tissue. Over the time, it may increase the risk of uterine cancer. When this compound was given to animals who did not produce natural oestrogens, it stopped the development of osteoporosis. In contrast, the animals who were given a placebo developed bone disease. Unlike the natural oestrogen, the designer variety is safer and does not cause uterine cancer.
The compound and other synthetic oestrogens called selective oestrogen-receptor modulators ( serms ) are essentially non-steroidal compounds. They are being developed by many leading pharmaceutical companies. A drug called raloxifene is very effective in preventing osteoporosis in post-menopausal women. The drug also reduces serum cholesterol. Unlike oestrogen, it does not alter the concentration of good cholesterol. Raloxifene's role in preventing osteoporosis is well established while its protective role in cardiovascular disease needs to be firmly established.
J E Compston at the University of Cambridge School of Medicine, Cambridge, uk , comments on the designer oestrogens, "In the Western countries, women now live nearly one-third of their lives after the menopause ( The Lancet , Vol 350, No 9079).