Study finds oestrogen-after-menopause link with ovarian cancer

CHICAGO - In another piece of the increasingly complex hormone-replacement health puzzle, researchers said today that women given oestrogen-only treatment after menopause ran a higher risk of ovarian cancer.

The report followed two other recently released studies that found oestrogen in combination with progestin -- a slightly less common replacement therapy than oestrogen-only -- does not generally protect against heart disease and may increase the risk of breast cancer, stroke and blood clots.

Hormone replacement therapy is prescribed to treat immediate symptoms such as hot flushes and vaginal dryness, and to protect against bone-thinning osteoporosis.

James Lacey of the National Cancer Institute, lead author of the oestrogen study published in this week's Journal of the American Medical Association, said there was not enough evidence to say if there was also an ovarian cancer risk from oestrogen-progestin use.

He offered this advice to women:

"Because hormone therapy may influence so many conditions ... after menopause -- cardiovascular disease, osteoporosis, breast cancer, uterine cancer, gallbladder disease, blood clots, and now 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 might be right for them."

Lacey's study involved more than 44,000 post-menopausal women whose health histories were tracked for about 20 years.

It found that compared to similar women not on hormone replacement therapy, those taking oestrogen only had a 60 per cent greater risk of developing ovarian cancer.

"The main finding of our study was that post-menopausal women who used oestrogen replacement therapy for 10 or more years were at significantly higher risk of developing ovarian cancer than women who never used hormone replacement therapy," Lacey said in a statement released by the cancer institute.

The institute said that as early as the 1940s women began using oestrogens in high doses to counteract some of the short-term discomforts of menopause; but after it became clear in the 1970s that it carried a high risk of uterine cancer, doctors began prescribing progestin, along with much lower doses of oestrogen.

Oestrogen only therapy continues to be widely prescribed today for women who have had a hysterectomy. The women in the NCI study varied -- some had undergone hysterectomy, but all had at least one ovary.

In an editorial in the same publication commenting on the study, Kenneth Noller of Tufts University and New England Medical Centre in Boston said the latest research as well as two recent studies including one from Sweden indicate that a causal connection could exist between oestrogen therapy and ovarian cancer.

"While the data from these observational studies do not establish causality, the association between oestrogen use and ovarian cancer should be worrisome enough for clinicians to consider carefully whether to suggest oestrogen-only HRT," he said.

He noted that it is still common for women who have had a hysterectomy but who retain one or both ovaries to be prescribed oestrogen-only therapy.

- REUTERS

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