In a secondary analysis of the phase III TAILORx trial reported in JAMA Oncology, Joseph Sparano, MD, and colleagues found that adjuvant chemotherapy plus endocrine therapy produced good 5-year outcomes among women with hormone receptor–positive, HER2-negative, axillary node–negative breast cancer and a high 21-gene recurrence score (RS) of 26 to 100.

Joseph Sparano, MD

The primary analysis of TAILORx showed that endocrine therapy alone was noninferior to adjuvant chemotherapy plus endocrine therapy in distant recurrence-free survival in the population of women with an RS of 11 to 25. In the trial, women with an RS of 26 to 100 were assigned to receive adjuvant chemotherapy and endocrine therapy.

Study Details

The current analysis included 1,389 women from the trial with an RS of 26 to 100 who received endocrine therapy plus investigator’s choice of adjuvant chemotherapy and were enrolled in a voluntary prospective registry. Chemotherapy regimens included docetaxel/cyclophosphamide in 589 women (42%); an anthracycline without a taxane in 334 (24%); an anthracycline plus a taxane in 244 (18%); cyclophosphamide/methotrexate/fluorouracil (CMF) in 52 (4%); other regimens in 81 (6%); and no chemotherapy in 89 (6%). Among the 1,389 women, 598 (42%) had an RS of 26 to 30 and 791 (58%) had an RS of 31 to 100.

Five-Year Outcomes

At 5 years among all patients, the estimated rate of freedom from recurrence at a distant site was 93.0%, freedom of recurrence at a distant or local regional site was 91.0%, invasive disease–free survival was 87.6%, and overall survival was 95.9%.

The 5-year rates of freedom from distant recurrence ranged from 92.3% to 95.5% for all chemotherapy regimens except CMF (88.5%); the 5-year rate was 92.8% in those receiving no chemotherapy. The 5-year rates of invasive disease–free survival ranged from 84.0% with CMF, to 88.6 with anthracycline/taxane, to 91.3% with other chemotherapy; the rate was 79.7% among those receiving no chemotherapy.

Analysis including only those patients who received chemotherapy showed a 5-year freedom from distant recurrence rate of 94.6% among patients with an RS of 26 to 30 and 91.9% among those with an RS of 31 to 100. The 5-year rates of invasive disease–free survival were 90.5% among patients with an RS of 26 to 30 and 86.3% among those with an RS of 31 to 100.

The investigators concluded, “The estimated rate of freedom from recurrence of breast cancer at a distant site in women with an RS of 26 to 100 treated largely with taxane and/or anthracycline-containing adjuvant chemotherapy regimens plus endocrine therapy in the prospective TAILORx trial was 93% at 5 years, an outcome better than expected with endocrine therapy alone in this population.”

Dr. Sparano, of Montefiore Medical Center, Albert Einstein College of Medicine, is the corresponding author for the JAMA Oncology article.

Disclosure: The study was supported by the National Cancer Institute and others. For full disclosures of the study authors, visit jamanetwork.com.