Correlation of Clinical Response to Pathologic Response in Patients With Early Breast Cancer

Neoadjuvant therapy was first introduced to improve surgical outcomes of breast cancer and to be able to assess the pathological responsiveness to therapy at the time of surgery. Over time, it became a useful experimental platform in clinical research in breast cancer, and in recent years became an important part of standard management of certain subtypes and clinical stages in breast cancer. It has been long established that patients who achieve pathologic complete response (pCR, i.e., the absence of any cancer in the tissue removed during surgery) after receiving neoadjuvant treatment have better outcomes than those who don't, especially in HER2+, and triple-negative breast cancer (TNBC). Many reports add aggressive ER+ breast cancer to these groups. So far, the only way to know whether a patient achieved pCR is to give them a full course of therapy and then proceed to surgery. One of the areas that has attracted significant research interest has been the effort to develop early predictors of pCR. This way, treatment can be tailored in the future to each patient and each tumor and can spare patients ineffective therapy. Some of these predictors include tissue biomarkers, blood based biomarkers, and imaging biomarkers. It has been observed in neoadjuvant clinical trials that many patients have an impressive early clinical response to treatment after 1-2 cycles of treatment. Anecdotally, many of those patients go on to have a pCR at the time of surgery. This observation, if validated in a prospective clinical trial, may lead to a simple, inexpensive way to assess tumor responsiveness and predict pCR using clinical exam and simple imaging. Using imaging or molecular changes to predict pCR will also be explored in this study. A consortium of investigators will be studying image analysis and proteogenomic changes early in the course of treatment to predict clinical response specifically in participants with TNBC. Only participants with TNBC will be required to undergo a research biopsy and research MRI prior to starting treatment, and again after the first cycle of treatment. The investigators therefore hypothesize that absence of early clinical response, defined as at least a 30% reduction in the size of the breast tumor by Day 21 of treatment (as measured by either imaging or clinical exam), will be associated with absence of pCR at the time of surgery, in 3 subtypes of breast cancer - TNBC, HER2+, high-risk ER+. All treatment in this study is standard of care (non-investigational).