Elevated Tumor-Infiltrating Lymphocytes

This study tests a new treatment approach for people with early-stage triple negative breast cancer whose tumors have a high number of immune cells, called tumor-infiltrating lymphocytes or TILs, as seen by a pathologist on tissue review. A high TIL count is a sign the cancer may respond especially well to chemotherapy and immunotherapy together, meaning more toxic treatment may not be needed for everyone. All patients with high TILs will receive 12 weeks of chemotherapy (carboplatin and paclitaxel) with the immunotherapy drug pembrolizumab before surgery, without anthracyclines, a class of chemotherapy drugs that is effective but carries risks of heart damage and, rarely, bone marrow disorders or leukemia. Patients with no cancer found at surgery continue on pembrolizumab alone. Those with residual cancer receive anthracycline-based chemotherapy plus pembrolizumab, closer to current standard treatment. The goal is to personalize treatment, sparing anthracyclines for patients likely to do well without them while reserving stronger therapy for those who need it. The main measure of success is the pathologic complete response rate, with cancer-free survival and overall survival also assessed.