Study: More Women Can Cut Cancer Relapse Risk

Women who survive breast cancer are often haunted by the fear that it might come back. But new research indicates that many more women than had been thought can do something to protect themselves.

Currently, women whose tumors were fueled by the hormone estrogen can take the drug tamoxifen after undergoing surgery, radiation and chemotherapy to reduce their risk of a recurrence. But tamoxifen only helps for five years. After that, it may be dangerous.

Five years ago, researchers stopped a large international study early when it showed that women who had early-stage breast cancer and who took another drug, known as an aromatase inhibitor, after tamoxifen were nearly half as likely to suffer a relapse. But many questions remained, including whether it would work for women who had been diagnosed years ago.

In the new research, Paul E. Goss of Massachusetts General Hospital and his colleagues looked at more than 1,500 women who had been taking a placebo in the original study but then started taking the aromatase inhibitor letrozole after the study was stopped. It had been at least a year and as many as seven years since they had stopped taking tamoxifen.

Even so, compared with the risk to about 800 women who did not start taking letrozole, the risk of a recurrence was cut by 63 percent. In addition, the risk of the cancer spreading was cut 61 percent, and the chance that a new tumor would be found in the other breast dropped more than 80 percent.

A second paper, also published online yesterday by the Journal of Clinical Oncology, answered another crucial question. Hyman Muss of the University of Vermont did further analysis of the original study and found that letrozole, which is sold under the brand name Femara, was effective in cutting the recurrence risk for women of all ages, including those older than 70.

A third study, involving 1,598 patients, found that a different aromatase inhibitor, known as exemestane or by the brand name Aromasin, was equally effective at reducing the recurrence risk.

Together, the research indicates a need for a "paradigm shift" in treating breast cancer survivors, Nancy U. Lin and Eric P. Winer of the Dana-Farber Cancer Institute wrote in an editorial accompanying the new research.