Study Measures Prognosis for Breast Cancer Patients with High 21-gene Recurrence Score Receiving Adjuvant Chemotherapy Plus Endocrine Therapy

A recent study published in JAMA Oncology analyzed outcomes for patients with early breast cancer with a high 21-gene recurrence score who underwent adjuvant chemotherapy plus endocrine therapy. The outcomes were superior compared to those associated with endocrine therapy alone.

“The 21-gene recurrence score (RS) assay provides prognostic information for distant recurrence in hormone–receptor-positive, ERBB2-negative early breast cancer that is independent of clinicopathologic features, and is also predictive of chemotherapy benefit when the RS is high,” the authors reported, adding, “In this report we provide a descriptive analysis of clinical outcomes, characteristics, and adjuvant chemotherapy regimens for patients with an RS of 26 to 100 assigned to receive chemotherapy, including regimens largely including taxanes and/or anthracyclines, plus endocrine therapy.”

The study was a secondary analysis of outcomes associated with the TAILORx trial. The multicenter, randomized clinical trial included women with hormone receptor–positive, ERBB2-negative, axillary node-negative breast cancer who had a high 21-gene recurrence score of 26 to 100. Patients received adjuvant chemotherapy, selected by the treating doctor, in conjunction with endocrine therapy. The primary outcome measure was freedom from breast cancer recurrence at a distant site and freedom from recurrence, second primary cancer, and death—or invasive disease-free survival (IDFS).

Of the 9,719 eligible total patients (mean age [range] 56 [23-75] years), 1,389 (14%) had a recurrence score between 26 and 100; of the high recurrence score group, 598 (42%) had a score between 26 and 30 and 791 (58%) had a score > 30. Regarding chemotherapy regimens, most patients (n = 589, 42%) received docetaxel/cyclophosphamide; 334 (24%) received an anthracycline without a taxane, 244 (18%) received an anthracycline and taxane, 52 (4%) received cyclophosphamide/methotrexate/5-fluorouracil, 81 (6%) received other regimens, and 89 (6%) did not receive chemotherapy.

After five years, the freedom from breast cancer recurrence at a distant site rate was about 93.0% (standard error [SE], 0.8%). Breast cancer recurrence at a distant and/or local regional site freedom was about 91.0% (SE, 0.8%); IDFS was about 87.6% (SE, 1.0%), and overall survival was about 95.9% (SE, 0.6%).

The authors wrote in sum, “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.”