Nearly 70 percent of women with a common type of early-stage breast cancer can undergo hormone therapy alone.
A MAJORITY OF WOMEN with early stages of a common type of breast cancer may safely be able to forego postoperative chemotherapy.
According to a long-awaited study presented Sunday at the American Society of Clinical Oncology, about 70 percent of women with early stages of the most common type of breast cancer can avoid chemotherapy and its debilitating side effects after surgery.
The findings were published in the New England Journal of Medicine and show that patients with an intermediate risk of cancer recurrence, which affects about 65,000 women a year in America, can avoid the post-op treatment and receive only hormone therapy, which has less severe side effects.
The study examined how well a vastly used genetic test assessed cancer risk based on 21 genes linked with breast cancer recurrence. It concluded that using this test to evaluate the risk of recurrence “can spare women unnecessary treatment if the test indicates that chemotherapy is not likely to provide benefit,” lead author Dr. Joseph Sparano said in a press release.
Sparano is the associate director for clinical research at the Albert Einstein Cancer Center and Montefiore Health System and vice chair of the ECOG-ACRIN Cancer Research Group. He said the results of the study, designed and led by the ECOG-ACRIN Cancer Research Group, “give clinicians high-quality data to inform personalized treatment recommendations for women.”
The study examined 10,273 women beginning in 2006 with hormone-receptor-positive, human epidermal growth factor receptor 2-negative, axillary node-negative breast cancer. Participants’ tumors were analyzed using the 21-gene expression tests and given a risk score from zero to 100 for cancer recurrence. Women with scores of zero to 10 (low risk) received only hormone therapy. Women with scores of 26 and above (high risk) were treated with both hormone and chemotherapy. Women with scores between 11 and 25 (intermediate risk) were randomly assigned to receive solely hormone therapy or a mix of the therapies.
At the end of the study, which was the largest of its kind, researchers found the number of women who had survived, developed a recurrence or a second primary cancer was very similar in both the hormone therapy-only group and the chemotherapy group. At five years, the overall survival rate was 98 percent for women who only received hormone therapy and 98.1 percent for women who received both therapies.
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Women with a score of zero to 10 also had very low recurrence rates – 3 percent – with a hormone-only treatment at nine years.
According to the press release, these results suggest that “chemotherapy is not beneficial for most women in the intermediate-risk group,” which was uncertain before the study.
“Before TAILORx, there was uncertainty about the best treatment for women with a mid-range score of 11–25 on the Oncotype DX Breast Recurrence Score test. The trial was designed to address this question and provides a very definitive answer,” Sparano said. “Any woman with early-stage breast cancer age 75 or younger should have the 21-gene expression test and discuss the results with her doctor to guide her decision to the right therapy.”