BREAST CANCER DRUG AIDS WIDE AGE RANGE.

Byline: Emma Ross Associated Press

The drug Tamoxifen, already standard treatment for older victims of breast cancer, works equally well in young women and could save an additional 20,000 lives a year around the world if given more widely, according to a study published today.

When taken immediately after surgery for five years, Tamoxifen halved the recurrence rate over the next 10 years - regardless of age - as well as the chances of developing a new cancer in the other breast, according to the study, described as the largest cancer study ever undertaken.

``The evidence is getting to be quite strong that these are permanent preventions - in other words, a cure,'' said Dr. Harmon Eyre, chief medical officer of the American Cancer Society. ``This takes it beyond any question of scientific debate.''

The study, by the Early Breast Cancer Trialists' Collaborative Group, was headed by scientists at Oxford University and published in this week's issue of The Lancet, a British medical journal. It is part of an ongoing analysis of all Tamoxifen studies ever conducted worldwide and followed 37,000 women with early breast cancer. It was funded by the Imperial Cancer Research Fund, an independent charity.

Breast cancer is described as early if it can be detected only in or near the breast and can be removed by surgery. However, microscopic fragments already might have spread elsewhere.

In most cases, breast cancer spreads as a result of hormones that encourage it to grow. Tamoxifen attacks spreading cancer by blocking these hormones. The drug does not help when women's tumors are insensitive to hormones.

With 1 million women worldwide taking it, Tamoxifen is one of the most widely used cancer drugs. But it is most often given to postmenopausal women. Younger women are mostly treated with chemotherapy alone because doctors did not believe Tamoxifen helped, theorizing that high hormone levels in premenopausal women might overwhelm the drug.

The new findings showed Tamoxifen was effective for women of all ages with hormone-sensitive cancer, whether or not chemotherapy had been given and whether or not the cancer had spread to their lymph nodes.

``Starting five years of Tamoxifen immediately after surgery prevented one in six women from relapsing and one in 12 from dying,'' said the study's leader, Richard Peto, professor of medical statistics and epidemiology at Oxford. ``Tamoxifen for older women is already saving more lives than any other cancer drug, but most of the young breast cancer patients who need Tamoxifen are not getting it.''

Peto's group started collecting all the breast cancer treatment studies conducted worldwide nearly 15 years ago. Early findings in the mid-1980s showed Tamoxifen could improve five-year survival. By 1992, the drug was shown to improve 10-year survival as well, but that was based on prescribing it for two years or less.

The latest information shows, however, that five years of Tamoxifen is about twice as effective.

Part of the reason why Tamoxifen is not being prescribed as widely as it could be is because the drug is linked to cancer of the womb and blood clots in the lung.