The X factor.

Adjuvant capecitabine improves disease-free and overall survival in patients with residual HER2- breast cancer following neoadjuvant systemic therapy. In practice, this approach is mainly used for triple negative disease. Most TNBC falls under the basal molecular subtype, which has a BRCA-ness phenotype that is associated with platinum sensitivity. The EA1131 trial sought to determine if adjuvant platinum (cis or carbo) was superior to capecitabine. Patients had stage II or III disease and were allowed to have 1-2+ hormone receptor positivity in 10% or fewer cells and had to be HER2 negative. They had to have a 1 cm or greater residual focus of disease in the breast regardless of nodal disease. Capecitabine was 1000 mg/m2 daily for 14 days every 3 weeks for 6 cycles. Cisplatin (12%) or carboplatin (88%) were given every 3 weeks for 4 cycles. At 3 years, there was no difference in the rate of invasive disease-free survival, and there was a significant increase in the rate of grade 3-4 toxicity with platinum chemo (26% vs 15%). | Mayer, J Clin Oncol 2021