After you find out you have breast cancer, your doctor may recommend a sentinel lymph node biopsy. This is a procedure used to see if cancer has spread beyond the place where it started and into the nearby lymph nodes. This type of biopsy is based on the idea that cancer cells spread in an orderly manner from where they start — first, to the sentinel lymph node(s), and then to other nearby lymph nodes before spreading to other organs in the body. The sentinel lymph node is the first lymph node to which cancer is likely to spread. In some cases, there can be more than 1 sentinel lymph node.
In a sentinel lymph node biopsy the sentinel lymph node is identified, removed, and examined under a microscope to see if cancer cells are present. This information may help the doctor determine the stage of the cancer (the extent of the spread of cancer in your body) and develop the best treatment plan for you. For instance, if the sentinel biopsy does not show cancer in your lymph node, your doctor may opt not to remove other underarm tissue and lymph nodes. Having your underarm lymph nodes removed isn’t a dangerous operation, but it can lead to a number of side effects, such as numbness due to nerve damage and a lifelong risk of swelling in your arm and chest (called lymphedema).
If your doctor suggests a sentinel lymph node biopsy, talk about why this may be needed and how it can help you. This type of biopsy requires a lot of skill and it should only be done by a surgical team with experience. Ask your doctor how many sentinel lymph node biopsies he or she has done.
During a sentinel lymph node biopsy, a specially trained surgeon injects a radioactive substance and/or dye near the tumor. This helps your surgeon locate the sentinel node so that he or she can remove it. Then, the surgeon sends it to a lab for examination.
If there is no cancer in the sentinel node then removing more nodes to look for cancer may not be necessary.
If there is cancer in the sentinel node, your surgeon may remove more of your underarm lymph nodes. This may be done at the same time or several days later, depending on how easily the cancer can be seen in the sentinel node at the time of surgery.
Sentinel node biopsy is often followed by breast-conserving surgery or a mastectomy.
This biopsy may be scheduled for the same time as breast-conserving surgery, or it can be done separately.