Good news for women with breast cancer: Many don't need chemo
"We can spare thousands and thousands of women from getting toxic treatment that really wouldn't benefit them," said Dr. Ingrid A. Mayer, from Vanderbilt University Medical Center, an author of the study.
The study found that gene tests on tumor samples were able to identify women who could safely skip chemotherapy and take only a drug that blocks the hormone estrogen or stops the body from making it. The hormone-blocking drug tamoxifen and related medicines, called endocrine therapy, have become an essential part of treatment for most women because they lower the risks of recurrence, new breast tumors and death from the disease.
"I think this is a very significant advance," said Dr. Larry Norton, of Memorial Sloan Kettering Cancer Center in New York. He is not an author of the study, but his hospital participated. "I'll be able to look people in the eye and say, 'We analyzed your tumor, you have a really good prognosis and you actually don't need chemotherapy.' That's a nice thing to be able to say to somebody."
The findings apply to about 60,000 women a year in the United States, according to Dr. Joseph A. Sparano of Montefiore Medical Center in New York, the leader of the study.
But Sparano and Mayer added a note of caution: The data indicated that some women 50 and younger might benefit from chemo even if gene-test results suggested otherwise. It is not clear why. But those women require especially careful consultation, they said. (Most cases of breast cancer occur in older women: The median age at diagnosis in the United States is 62.)
The study, called TAILORx, is being published by The New England Journal of Medicine and was to be presented Sunday at a meeting of the American Society of Clinical Oncology in Chicago. The study began in 2006 and was paid for by the U.S. and Canadian governments and philanthropic groups. Genomic Health, the company that makes the gene test, helped pay after 2016.
This year, about 260,000 new cases of breast cancer are expected in women in the United States, and 41,000 deaths. Globally, the most recent figures are from 2012, when there were 1.7 million new cases and more than half a million deaths.
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