Study: Breast cancer treatment cuts recurrence by 40%

Breast cancer patients who follow up tamoxifen treatment with letrozole, an estrogen suppressor, cut risk of recurrence by 40%, according to a study published online Thursday by the New England Journal of Medicine. The study, involving more than 5,000 women who had the most common form of breast cancer, was suspended halfway through its planned five-year time span because of the surprisingly strong results. The journal also moved up publication of the study, which will appear in the November 6 print issue, because of the importance of the findings. The study, conducted by 18 doctors from various Canadian, U.S., and European hospitals, universities, and cancer centers, found that women with estrogen-sensitive breast cancer who had completed five years of tamoxifen treatment and then took letrozole were about 40% less likely to have the cancer return or get a new tumor in the other breast than those who received a placebo after tamoxifen. Letrozole, made by pharmaceutical company Novartis, is an aromatase inhibitor that blocks production of estrogen. Side effects include increased risk of osteoporosis, hot flashes, night sweats, and pain in the bones, joints, or back. Estrogen fuels the growth of about half of all breast cancers, especially those in older women. Tamoxifen, the top hormonal treatment for estrogen-fueled tumors, is given to almost all such U.S. patients after surgery to help prevent breast tumors from returning. In addition, when breast cancer returns and spreads, tamoxifen is the top treatment to stall tumor growth. It prevents estrogen from linking up to a receptor on the surface of cancer cells.