For some people, breast cancer treatment begins with neoadjuvant therapy, which is given before surgery. Neoadjuvant therapy can include chemotherapy, HER2-targeted therapy, hormone therapy and/or immunotherapy. Neoadjuvant therapy can shrink cancer in the breast and axillary lymph nodes. In some cases, it may shrink a tumor enough to allow a lumpectomy instead of a mastectomy. Pathology reports can look different for people who get neoadjuvant therapy compared to those who have surgery first.

Before neoadjuvant therapy, the stage of breast cancer is determined by imaging, such as mammograms, and by a physical breast exam. This is called the clinical prognostic stage. After surgery, the stage of breast cancer is determined by a pathologist’s examination of tissue removed during surgery. This is called the pathological stage and gives the most detailed information about prognosis. Breast cancer is staged using the TNM system. When TNM is reported after neoadjuvant therapy, a lower case “y” will appear before the Tumor and Node categories on the pathology report. Otherwise, the staging categories are the same as for tumors not treated with neoadjuvant therapy. Since neoadjuvant therapy is only used for non-metastatic breast cancer, the pathology report will list “M0.” After surgery, a pathologist will examine the tissue removed and take measurements which will be included in the pathology report. The largest measurement of the tumor is reported as the tumor size. If there’s more than one area of cancer in the breast, the largest continuous area is reported as the tumor size. After neoadjuvant therapy, tumor size is labeled with “ypT” before other identifying numbers or letters. The “y” means the measurement was taken after neoadjuvant therapy, the “p” means a pathologist took the measurement from tissue removed during surgery and the “t” refers to the tumor. If there’s more than one area of cancer in the breast, it’s reported with the letter “m.” Lymph node status is reported the same way whether or not you receive neoadjuvant therapy. The only difference is that “yp” appears before the “N” on the report. If the status of lymph nodes is reported before treatment, it’s designated with a “cN.” The pathologist’s findings may also be used to determine how well the cancer responded to neoadjuvant therapy which helps predict prognosis. If no sign of cancer is found in the breast or axillary lymph nodes, this is called a pathologic complete response, or pCR. If any cancer remains in the breast or axillary lymph nodes, it’s called residual breast cancer, and it may be reported as a Residual Cancer Burden or RCB score. A higher RCB score means more cancer remains in the breast and lymph nodes. For more information on pathology reports, visit the Diagnosis section on komen.org.