“This is a really big deal,” said Dr. Adam Brusky, a coauthor on the new study and a professor of medicine at the University of Pittsburgh. The bottom line, Brusky said, is that doctors now have a test to determine which early-stage patients — and that’s most of them — can skip chemotherapy.
Of the more than 250,000 women in the U.S. expected to be diagnosed with breast cancer, the new findings could benefit more than 63,000 with non-invasive, or early stage, disease.
Women with cancer are given scores that come from genetic tests that analyze the tumors and look for the presence of 21 genes that have been associated with a high likelihood of recurrence. Until now, doctors didn’t know for sure whether to offer chemotherapy to a large percentage of patients with early stage cancer.
The new study, dubbed the TAILORx trial, followed 9,717 women with early-stage disease, ages 18 to 75, with estrogen-receptor-positive, HER2-negative cancers that had not spread to the lymph nodes — cases where doctors have been unsure whether chemo would be helpful.
Of the 9,717 women, 6,711, or 67 percent, had test scores indicating an intermediate risk of recurrence — their score was 11 to 25. After surgery and radiation, those women were randomly assigned to receive chemotherapy with an estrogen-blocking medication or just the estrogen hormone blocker.
Prior to the study, doctors knew women with a low score on the test, less than 11, were told they could skip chemo with no ill effects. Women at high risk, or scores of 26 or higher, were advised to have chemo.
The new study showed that women with intermediate risk, it made no difference in terms of recurrence whether a woman was treated with chemotherapy or not.
“We didn’t know if chemotherapy benefited women in this range,” said Dr. Sara Hurvitz, an associate professor at the University of California, Los Angeles, and director of breast medical oncology at the UCLA/Jonsson Comprehensive Cancer Center. “The study showed that if you take the group as a whole, there is no difference in the risk of recurrence when you compare chemotherapy to no chemotherapy.”
Nine years after their initial treatment 83.3 percent of women treated with just an anti-estrogen medication and 84.3 percent in the anti-estrogen plus chemotherapy group were cancer free. Further, 94.5 percent of those treated with just an estrogen blocker and 95 percent of those treated with anti-estrogen plus chemo, had no recurrence at a distant site.
Some cancer specialists have been postponing the decision to treat their newer patients with chemotherapy until the study findings were released.