Most women with the most common form of early-stage breast cancer can safely skip chemotherapy without hurting their chances of beating the disease, doctors are reporting in a landmark study that used genetic testing to gauge each patient's risk. The study is the largest ever done of breast cancer treatment, reports the AP, and the results are expected to spare up to 70,000 US patients a year the ordeal and expense. "The impact is tremendous," said study leader Dr. Joseph Sparano of Montefiore Medical Center in New York. Most women don't need treatment beyond surgery and hormone therapy, and "the rest of them are receiving chemotherapy unnecessarily." Results were discussed Sunday at an American Society of Clinical Oncology conference in Chicago and published by the New England Journal of Medicine.
About 17% of women had high-risk scores and were advised to have chemo. The 16% with low-risk scores now know they can skip chemo, based on earlier results in this study. The new results are on the 67% of women at intermediate risk. All had surgery and hormone therapy, and half also got chemo. After nine years, 94% of both groups were still alive, and 84% were alive without cancer, so adding chemo made no difference. Certain women 50 or younger did benefit from chemo; slightly fewer cases of cancer spreading far beyond the breast occurred among some given chemo, depending on their risk scores. Testing solved a big problem of figuring out who needs chemo, said Dr. Harold Burstein of the Dana-Farber Cancer Institute. Many women think "if I don't get chemotherapy I'm going to die, and if I get chemo I'm going to be cured," but the results show there's a sliding scale of benefit and sometimes none.