Understanding Your Pathology Report After Neoadjuvant Therapy
For some people with breast cancer, treatment begins with chemotherapy, HER2-targeted therapy, immunotherapy and/or hormone therapy, rather than surgery. This is called neoadjuvant therapy or preoperative therapy.
The goal of neoadjuvant therapy is to shrink the cancer in the breast and/or lymph nodes in the underarm area (axillary lymph nodes). Neoadjuvant therapy may shrink a tumor enough so a lumpectomy becomes an option to a mastectomy.
Information on a pathology report is a bit different for people who get neoadjuvant therapy compared to those who get surgery as their first treatment. This page describes pathology reports, including the information used in breast cancer staging, for people who get neoadjuvant therapy.
Neoadjuvant therapy and breast cancer staging
Breast cancers treated with neoadjuvant therapy are staged a bit differently than those treated with surgery first.
Before neoadjuvant therapy begins, the pre-treatment stage of your breast cancer may be determined using imaging (such as mammograms) and findings from a physical exam of the breast. This is called clinical prognostic stage.
After surgery, the stage of your breast cancer is determined using pathology information from the tissue removed during surgery. The pathologic stage after neoadjuvant therapy gives the most information on your prognosis (chances for survival).
TNM staging system and neoadjuvant therapy
The main method of pathologic staging for breast cancer is the TNM system which stands for (Tumor size, lymph Node status and Metastases).
When TNM is used after neoadjuvant therapy, you’ll see a “y” before the T and N measures on your pathology report. Otherwise, the categories are the same as those for tumors not treated with neoadjuvant therapy.
yT = Tumor stage after neoadjuvant therapy
yN = Lymph node status after neoadjuvant therapy
Metastatic status is determined before treatment begins.
M0 = No metastases
M1 = Metastases
Neoadjuvant therapy is only used to treat non-metastatic breast cancer. So, if you get neoadjuvant therapy, you should see “M0” on your pathology report.
Clips mark the location of the breast cancer
During the biopsy that diagnosed breast cancer, a clip may have been placed in your breast to mark the location of the cancer. This clip helps guide the surgeon to the tumor bed during surgery. Sometimes, neoadjuvant therapy shrinks breast cancer so much it can be hard to find the tumor bed without this clip.
Similarly, if a lymph node with cancer was found before treatment began, a clip may have been placed to mark its location. That way, the surgeon can find and remove the lymph node during surgery, even if neoadjuvant therapy shrinks the node.
Clips are usually removed during surgery.
Neoadjuvant therapy and surgery
Neoadjuvant therapy may shrink a tumor enough so a lumpectomy becomes an option to a mastectomy.
Sometimes, imaging shows there’s no cancer left in the breast after neoadjuvant therapy. However, you will still have breast surgery.
There may be some cancer left in the tumor bed (the original site of the breast cancer) that’s too small to see on imaging. So, tissue from the tumor bed must be removed and checked to be sure.
How well did the tumor respond to neoadjuvant therapy?
After surgery, a pathologist studies the breast tissue removed. The pathologist’s findings are used to determine how well the breast cancer responded to neoadjuvant therapy. This information may be included on your pathology report.
The breast cancer’s response to neoadjuvant treatment gives useful information about prognosis (chances for survival).
Pathologic complete response
Sometimes, the pathologist’s exam shows no sign of cancer in the breast or axillary lymph nodes. This is called a pathologic complete response (pCR) and means the neoadjuvant therapy got rid of all the breast cancer.
If you have a pCR, it will be noted on your pathology report.
Learn more about pathologic complete response.
Residual breast cancer
Any breast cancer that remains in the breast or axillary lymph nodes after neoadjuvant therapy is called residual breast cancer. Many people have some residual breast cancer after neoadjuvant therapy.
Your pathology report will include whether or not residual breast cancer was found in the breast and/or lymph nodes.
Residual cancer burden
Sometimes, information about residual cancer burden (RCB) is included on your pathology report.
An RCB score is determined using information on the size of the tumor and the extent of tumor cells in the breast and axillary lymph nodes after neoadjuvant therapy.
The higher the RCB score, the more residual breast cancer there is in the breast and lymph nodes:
- RCB-0 = No residual breast cancer
- RCB-I = Small amount of residual breast cancer
- RCB-II = Moderate amount of residual breast cancer
- RCB-III = Extensive (a lot of) residual breast cancer
Learn more about the contents of a pathology report.
Pathology tests repeated after surgery for breast cancer
Sometimes, tests done on the pre-treatment biopsy tissue (the tissue that diagnosed the breast cancer), such as tests for hormone receptors status and HER2 status, are repeated on the tissue removed during breast cancer surgery.
It’s not clear whether repeating these tests is helpful to guide prognosis (chances for survival) or treatment.
Other information on a pathology report
Other information on a pathology report is the same for people who have neoadjuvant therapy and those who have surgery as their first breast cancer treatment.
Learn more about the contents of a pathology report.
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