Sentinel lymph node biopsy
Checking the first lymph nodes cancer would reach
The short version
A sentinel lymph node biopsy identifies and removes the first one or few lymph nodes cancer cells would likely reach, to check whether cancer has spread there — often done at the same time as breast surgery.
A sentinel lymph node biopsy identifies the "sentinel" nodes — the first lymph nodes that fluid (and potentially cancer cells) would drain to from the tumor — using a tracer injected before surgery. These nodes are removed and examined; if they're free of cancer, it's often unnecessary to remove more nodes.
Removing only the sentinel nodes, rather than all the nodes under the arm, is generally associated with a lower risk of lymphedema (arm swelling) when the sentinel nodes are cancer-free.
Questions you may want to ask
Will this be done at the same time as my other breast surgery?
What happens if the sentinel nodes show cancer cells?