The Primary Objective is to characterize the circulating tumor DNA (ctDNA) profile of triple-negative breast cancer (TNBC) in participants with residual disease after standard neoadjuvant chemotherapy (NAC) receiving standard-of-care adjuvant capecitabine.~The Secondary Objectives are to correlate ctDNA levels with genomic features and survival.
The purpose of the study is to evaluate the use of a circulating tumor DNA (ctDNA) assay, ie, a liquid biopsy, as a tool to identify triple-negative breast cancer (TNBC) patients who will or will not experience benefit from treatment with capecitabine. Participants will be monitored for changes in ctDNA in the blood over time received during capecitabine treatment. Results of ctDNA analysis will be correlated to genetic characteristics of individual tumors. This may inform future clinical trials in which patients could receive a different treatment than capecitabine to reduce their risk of breast cancer relapse.