Beating Breast Cancer

By Christine Gorman

For women facing the trials and terrors of breast cancer, the worst part of the ordeal -- worse even than the possibility of losing a breast -- is the sense that the nightmare is not over even after the stitches heal. Breast cancer strikes 1 out of 9 women in industrialized countries and recurs in a third of all patients within five years of their initial diagnosis and in more than half within 10 years.

The grim statistics have led most women and their doctors to opt for additional treatment beyond surgery: radiation, chemotherapy with toxic drugs, and hormonal therapy with tamoxifen pills, which block the estrogens that can stimulate tumor growth. Though millions of research dollars and hours have been poured into determining which treatments work best for which patients, the results have often been contradictory and confusing.

Now, thanks to a gigantic study published in last week's issue of the British medical journal Lancet, the choice of treatment should be clearer. Tamoxifen, alone or combined with other therapies, will become the treatment of choice for a greater number of patients than ever before.

Led by epidemiologist Richard Peto, researchers at Oxford University pooled together the raw data from 133 studies conducted around the world on 75,000 women with operable breast cancer over the past four decades. Using a complex and unusual statistical process, they found that for women with early cancer, tamoxifen boosted 10-year survival rates from 71% to 75%. Although that kind of advance seems incremental, it translates into tens of thousands of lives each year.

For women with somewhat more advanced tumors, the study showed, combining tamoxifen with other therapies greatly improved survival rates. Furthermore, tamoxifen alone, which produces few side effects, reduced the risk of cancer spreading to the other breast by 40%.

The drug's benefits were clear in both young and old patients. Most surprising, tamoxifen seemed to help even those women whose tumors were not of the type whose growth depends on estrogen. "The drug probably has other mechanisms of action," says Dr. Andrew Dorr of the National Cancer Institute. "It may be a tumor suppressor in and of itself."

Though most patients receiving tamoxifen stop taking the pills after a few years, last week's report showed that the benefits seem to last longer than anyone had realized. "Women on tamoxifen for just two years had a decreased chance of dying 10 years later," observes Dr. I. Craig Henderson of Harvard, an organizer of the study.

The Oxford study was a milestone not only in breast-cancer research but also in the use of a new statistical technique called meta-analysis, which enables researchers to pool data from many studies and compare otherwise incomparable results. The technique was recently used in a major study revealing the benefits of aspirin in treating heart disease. "It is emerging as an important tool in medicine," says Dorr, and one that can be deployed without the considerable costs and risks of a large clinical trial.