Question: What can you tell me about sentinel node biopsy? Can I trust the results?
Lymph nodes are filters that trap cancer cells (and other unwanted cells) and eliminate them from the body. Pathologists check lymph nodes for cancer cells that have left the tumor and are trying to spread.
The presence ("node-positive") or absence ("node-negative") of cancer in the lymph nodes is one of the most important factors your doctor will consider when determining how aggressive your treatment needs to be. Read more about what lymph node involvement means.
In both types of lymph node dissection, lymph nodes are removed from the underarm area next to the breast. A pathologist checks to see if they have cancer cells in them. In sentinel node biopsy, fewer lymph nodes are removed.
Doctors once thought that removing as many lymph nodes as possible would reduce the risk of cancer ever spreading. Doctors also wanted to remove as many lymph nodes as possible to get a better idea of how many lymph nodes were affected by cancer. Sentinel node biopsy has changed the way doctors think about this issue.
In sentinel node dissection, the surgeon looks for the sentinel node or nodes, which is the first lymph node or first few nodes that filter fluid draining away from the breast. If cancer cells are traveling in the lymph system, the sentinel node is more likely than the others to contain them. So, rather than remove 10 or more nodes, surgeons remove only the one node, or a cluster of two or three, which is most likely to have cancer. If the sentinel node is clean, chances are the other nodes are clean, too.
But it's important to remember that sentinel node biopsy is not appropriate for everyone. In 2014, the American Society of Clinical Oncology released guidelines on sentinel lymph node biopsy. The guidelines say sentinel lymph node biopsy SHOULD be offered under these circumstances:
- breast cancer in which there is more than one tumor, all of which have formed separately from one another (doctors call these multicentric tumors); these types of breast cancers are rare
- DCIS treated with mastectomy
- women who have previously had breast cancer surgery or axillary lymph node surgery
- women who have been treated before with chemotherapy or another systemic treatment (treatment before surgery is called neoadjuvant treatment)
Sentinel node biopsy SHOULD NOT be offered under these circumstances:
- the cancer is 5 cm or larger or locally advanced (the cancer has spread extensively in the breast or to the nearby lymph nodes)
- the cancer is inflammatory breast cancer
- DCIS treated with lumpectomy
- the woman is pregnant
The guidelines also say:
- Women with negative sentinel node biopsies shouldn’t have axillary node surgery.
- Women with one or two positive sentinel nodes who plan to have lumpectomy plus radiation also don’t need axillary node surgery.
- Women who have one or more positive sentinel nodes and plan to have mastectomy with no radiation should be offered axillary node surgery.