Ovarian cancer fear over oestrogen-only therapy

By ANGELA GREGORY health reporter

New research shows a significant increase in the risk of ovarian cancer with the use of oestrogen-only hormone replacement therapies.

But a cancer specialist says there is no reason for the thousands of New Zealand women who take oestrogen-only medication to panic.

Dr Vernon Harvey, an Auckland Hospital medical oncologist, said the findings of the American study were surprising. "It goes against what we had normally thought, that hormones protected from ovarian cancer."

But Dr Harvey said the risk of ovarian cancer was very low, even when taking into account the new research.

"It is not a reason for them to stop taking the medication before discussing it with their doctors. There are always questions of balancing the benefits and disadvantages. This might be one of many small disadvantages."

Ministry of Health spokesman Stewart Jessamine said women taking oestrogen-only hormone replacement therapy should discuss with their doctors at their next visit the risks and benefits of long-term treatment.

The study, published in the Journal of the American Medical Association, found that women who used oestrogen-only hormone replacement therapy (HRT), particularly for 10 or more years, were at significantly increased risk of ovarian cancer.

Oestrogen-only therapy is widely available in New Zealand in a subsidised drug called Premarin. The therapy is prescribed to treat immediate symptoms of menopause such as hot flushes and vaginal dryness and to protect against bone-thinning osteoporosis.

In the study of 44,241 postmenopausal American women, 329 women developed ovarian cancer during follow-up. The use and increased duration of oestrogen-only HRT were significantly associated with the cancer.

The study found that women who used short-term combination oestrogen-progestogen HRT were not at increased risk but that the results warranted further investigation with long-term use.

The latest research follows close on the heels of a study of 16,608 postmenopausal American women who took combined oestrogen-progestogen HRT. The research found an increased risk of breast cancer, coronary heart disease and strokes.

James Lacey of the National Cancer Institute, lead author of the oestrogen study, said not enough evidence was available to say if there was also an ovarian cancer risk from oestrogen-progestin use.

"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."

Dr Lacey said the women's health histories had been tracked for about 20 years.



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 indicated 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."