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 from a landmark study that used genetic testing to gauge each patient’s risk.
The study is the largest ever done of breast cancer treatment, and the results are expected to spare up to 70,000 patients a year in the United States and many more elsewhere the ordeal and expense of these drugs.
“The impact is tremendous,” said the study leader, Dr. Joseph Sparano of Montefiore Medical Center in New York. Most women in this situation don’t need treatment beyond surgery and hormone therapy, and “the rest of them are receiving chemotherapy unnecessarily.”
The study was funded by the National Cancer Institute, some foundations and proceeds from the US breast cancer postage stamp. Results were discussed Sunday at an American Society of Clinical Oncology conference in Chicago and published by the New England Journal of Medicine. Some study leaders consult for breast cancer drugmakers or for the company that makes the gene test.
About 17 per cent of women had high-risk scores and were advised to have chemo. The 16 per cent with low-risk scores now know they can skip chemo, based on earlier results from this study. The new results are on the 67 per cent of women at intermediate risk. All had surgery and hormone therapy, and half also got chemo. After nine years, 94 per cent of both groups were still alive, and about 84 per cent were alive without signs of cancer, so adding chemo made no difference.