A majority of women with the most common type of breast cancer can to opt out of chemo without changing their outcome, according to research published this summer in the New England Journal of Medicine.
New findings from the groundbreaking Trial Assigning Individualized Options for Treatment (Rx), or TAILORx trial, show no benefit from chemotherapy for 70 percent of women with the most common type of breast cancer.
The study found that for women with hormone receptor (HR)-positive, HER2-negative, axillary lymph node-negative breast cancer, treatment with chemotherapy and hormone therapy after surgery is not more beneficial than treatment with hormone therapy alone.
The new data, released at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago, will help inform treatment decisions for many women with early-stage breast cancer.
Dr. Mark Taylor, an oncologist with Summit Cancer Care in Savannah, was the investigator for the trial at the Nancy N. and J.C. Lewis Cancer and Research Pavilion at St. Joseph’s/ Candler, which was one of 1,182 trial sites in the U.S. Australia, Canada, Ireland, New Zealand and Peru.
“We’re thrilled to get further and further away from chemo,” he said. “We’re getting further away from chemo in all kinds of cancers, and breast is no exception. And the TAILORx study was important in sort of furthering that movement.”
He explained that the goal of the trial was to focus in on a specific subset of women that previously would have been given chemo by default to err on the side of caution.
“There was a group of women we knew already didn’t get chemo, so that was no revelation. And there was a group that’s high risk that would still get chemo. The TAILORx was just looking at that intermediate group,” Taylor said.
“It was basically just trying to move the goal posts narrower – figuring out more women in that intermediate group that don’t need chemo and making sure you’re clearly identifying women who do need chemo.”
TAILORx was a phase 3 clinical trial that opened in 2006 and used a molecular test that assesses the expression of 21 genes associated with breast cancer recurrence to assign women with early-stage, HR-positive, HER2-negative, axillary lymph no denegative breast cancer to the most appropriate and effective post-operative treatment.
The trial enrolled 10,273 women with this type of breast cancer. When patients enrolled, their tumors were analyzed using the 21-gene expression test and assigned a risk score, on a scale of 0100, for cancer recurrence. Based on evidence from earlier trials, women who had a score in the low-risk range, 010, received hormone therapy only. and those who had a score in the high-risk range, 26 and above, were treated with hormone therapy and chemotherapy.
Women who had a score in the intermediate range, 1125, were randomly assigned to receive hormone therapy alone or hormone therapy with adjuvant chemotherapy. The goal was to assess whether women who received hormone therapy alone had outcomes that were as good as those among women who received chemotherapy in addition to hormone therapy.
Five years after treatment, the rate of invasive disease-free survival – women who had not died or developed a recurrence or a second primary cancer – was 92.8 percent for those who had hormone therapy alone and 93.1 percent for those who also had chemotherapy.
At nine years, the rate was 83.3 percent for those with hormone therapy alone and 84.3 percent for the group that had both therapies.
None of these differences were considered statistically significant.
The rates of overall survival were also very similar in the two groups. At five years, the overall survival rate was 98.0 percent for those who received hormone therapy alone and 98.1 percent for those who received both therapies, and at nine years the respective overall survival rates were 93.9 percent and 93.8 percent.
There is one caveat to the new findings.
When the researchers analyzed premenopausal women and those younger than 50 years old at the higher end of the intermediate- risk range (16-25) separately, the results showed there may be a small benefit from chemotherapy, and thus these women should consider chemotherapy with their doctor.
“This is still not cut and dry. You have to talk to your oncologist, and there will be nuances that may make the overall headline (of the trial) not apply to you,” Taylor said. “But there’s no doubt about it, it was a good study.”