The addition of adjuvant capecitabine provided no survival benefit for patients with early triple-negative breast cancer who had undergone surgery and standard chemotherapy, according to a randomized, global, phase 3 GEICAM/CIBOMA clinical trial (ClinicalTrials.gov Identifier: NCT00130533). The exception to this, however, may be in patients with nonbasal-like disease. The trial results were presented at the 2018 San Antonio Breast Cancer Symposium (SABCS) in Texas.1
The trial enrolled 876 patients with early triple-negative breast cancer that was node-positive and who had undergone surgery and standard chemotherapy. Node-negative disease was included if the tumor size was 1 cm or greater. Stratification factors included institution site, phenotype (basal vs nonbasal), prior chemotherapy regimen, and involvement of axillary lymph nodes.
Patients were randomized in a 1:1 fashion to receive either 8 cycles of capecitabine or to be observed. The primary endpoint was disease-free survival (DFS), and secondary endpoints included overall survival (OS) and subgroup analyses.
The patient and tumor characteristics between both arms were “well balanced,” according to study presenter Miguel Martín, MD, PhD, professor of medicine and head of the Medical Oncology Service at Hospital Gregorio Marañón, Universidad Complutense in Madrid, Spain.
At a median follow-up of 7.34 years, the 5-year DFS was 79.6% for the capecitabine arm and 76.8% for the observation arm; the adjusted hazard ratio was 0.79 (95% CI, 0.61 – 1.03; P = .082). The 5-year OS was also similar between arms, with 86.2% of patients in the capecitabine arm and 85.9% of patients in the observation arm still alive at 5 years (HR = 0.92; 95% CI, 0.66 – 1.28; P = .623).
Dr Martín described the trial results as “formally negative” because statistical significance was not reached for the primary endpoint.
The prospectively planned subgroup analysis, however, showed a statistically significant survival benefit for patients with nonbasal-like disease who received capecitabine. The 5-year DFS was 82.6% for patients with nonbasal-like disease in the capecitabine arm compared to 72.9% in the observation arm (HR = 0.53; 95% CI, 0.31 – 0.91; P = .020). The 5-year OS was 89.5% for patients with nonbasal-like disease in the capecitabine arm compared to 79.6% in the observation arm (HR = 0.42; 95% CI, 0.21 – 0.81; P = .007).
Barbara Jacoby is an award winning blogger that has contributed her writings to multiple online publications that have touched readers worldwide.