Early Detection of Triple Negative Breast Cancer Relapse (CUPCAKE)

This study is developing and testing a blood-based test (circulating tumor DNA, or ctDNA) to detect very early signs of triple-negative breast cancer (TNBC) returning, so that treatment can be started before a full relapse becomes visible on imaging. **You may be eligible if...** - You are a woman 18 years old or older - You have been diagnosed with non-metastatic triple-negative breast cancer - You had surgery to remove the cancer between 3 and 9 months before joining the study - You are considered high-risk (cancer did not completely disappear with pre-surgery chemotherapy, or was stage IIB or higher) - You have started any planned additional (adjuvant) treatment at least 12 weeks ago - There are no current signs of cancer returning **You may NOT be eligible if...** - You are male - Your cancer has already spread to other organs - You have had another cancer in the past 5 years (except certain early-stage or skin cancers) - You have a condition that would prevent you from following study procedures Talk to your doctor to see if this trial is right for you.