Should All High-Risk Early Breast Cancer Patients Receive Chemotherapy?

A 21-gene assay is effective in guiding the use of adjuvant chemotherapy in patients with early breast cancer, according to a recent analysis of the TAILORx trial. 

The findings, presented at the European Society for Medical Oncology (ESMO) 2019 Congress, held September 27-October 31 in Barcelona (Abstract LBA18), focused on patients with high recurrence scores based on that assay (scores from 26-100), and found that treatment with various chemotherapy regimens can improve outcomes over endocrine therapy alone.

“It is known that the 21-gene recurrence score in hormone receptor-positive, HER2-negative breast cancer is not only prognostic for distant recurrence with endocrine therapy in multiple cohorts, but also is predictive of chemotherapy benefit when added to endocrine therapy in node-negative, HER2-negative breast cancer,” said Joseph A. Sparano, MD, of the Albert Einstein College of Medicine, who presented the new results at ESMO. “There is limited data on outcomes in high recurrence scores treated with taxanes and/or anthracyclines.”

The new analysis was focused on the “High Risk Registry” portion of the TAILORx trial; it included a total of 1,389 patients with recurrence scores of 26-100 who were followed for a median of 61 months. They had a median age of 56 years, and 57% were considered at clinical high risk. The median recurrence score was 32, with 57% of patients falling in the 31-100 range and 43% in the 26-30 range, according to the data.

The most common chemotherapy regimen among these patients was docetaxel and cyclophosphamide (42% of patients), followed by an anthracycline without a taxane (24%), an anthracycline plus a taxane (18%), cyclophosphamide/methotrexate/5-FU (4%), and other regimens in 6% of patients, the study showed.

At five years, 93.0% of patients were distant relapse free, and the invasive disease-free survival (IDFS) rate was 87.6%. At nine years, those rates were 86.8% and 75.7%, respectively. Results were generally good for distant relapse-free interval across the various chemotherapy regimens, ranging from 88.5% with cyclophosphamide/methotrexate/5-FU up to 95.1% with an anthracycline and a taxane and 95.5% with other regimens.

A comparison of the actual outcomes for patients treated with chemotherapy plus endocrine therapy and the expected outcomes for those treated with endocrine therapy alone substantially favored the addition of chemotherapy. For IDFS, at five years the actual outcome with the combination was 88.1%, compared with an expected outcome of 74.7% with endocrine therapy alone. At nine years, those rates were 76.2% and 55.3%, respectively, according to the results.

“This adds to the evidence base supporting the use of the 21-gene assay to guide use of adjuvant chemotherapy,” Sparano said. “Outcomes with chemotherapy plus endocrine therapy are better than expected with endocrine therapy alone.”

Antonio L. Cussac, MD, PhD, of the Hospital Universitario Arnau de Vilanova in Lleida, Spain, discussed the study for ESMO. He noted that TAILORx did not randomize the high-recurrence score patients, and it was not designed to evaluate specific chemotherapy regimens. Still, most of the regimens used were consistent with available literature. He said that it is “very clear” that adding chemotherapy to endocrine therapy does offer benefit, and that all patients with a risk score above 25 should be offered chemotherapy.

References:

Sparano J, Gray R, Makower D, et al. Clinical Outcomes by Chemotherapy Regimen in Patietns with RS 26-100 in TAILORx. ESMO 2019 Congress. Presented September 30, 2019.