Many women with early-stage breast cancer who would receive chemotherapy under current standards do not actually need it, according to a major international study that is expected to quickly change medical treatment.
“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. “This is very powerful. It really changes the standard of care.”
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.”