lymph node dissection
Meaning of lymph node dissection: Removing a block of nodes tells surgeons how far a cancer has traveled, at the cost of the drainage those nodes provided.
Definition of lymph node dissection
A lymph node dissection is an operation that removes a group of lymph nodes from the region draining a tumor so a pathologist can examine them for cancer cells. The nodes are taken as a block of tissue rather than sampled one at a time. The extent varies from a limited regional clearance to removal of nearly every node in the area.
Why are the nodes removed at all?
Fluid drains away from a tumor along predictable channels and passes through nodes on the route. Cancer cells that break loose travel the same way, so the nodes nearest a tumor are where spread usually shows up first. Removing them serves two purposes at once. Under the microscope they answer how far the disease has reached, which sets the stage and shapes what treatment follows. Their removal also clears deposits too small to see or feel, which is treatment rather than testing. The same operation is called a lymphadenectomy.
How much tissue is taken?
That depends on what the nodes are being asked to answer.
| Approach | What is removed | Usual purpose |
|---|---|---|
| Sentinel node biopsy | Only the first node or two the tumor drains into | Staging with the least disturbance |
| Regional dissection | Part of the draining group of nodes | Staging, and clearing limited disease |
| Radical dissection | Most or all nodes in the area, with surrounding fat | Clearing known or heavy involvement |
Mapping the drainage first with a dye or a tracer identifies the sentinel lymph node. When that node is clear, the ones beyond it usually are too, which is why a negative sentinel result spares many people a full clearance.
What does removing them cost?
Nodes are junction boxes in a drainage network, and taking them out leaves fluid with fewer routes home. Persistent swelling of the limb below, called lymphedema, is the characteristic late consequence, and it can begin months or years afterward. It becomes more likely as more nodes are taken, and more likely again when radiation is given to the same area. Shorter-lived effects include a fluid collection under the wound, numbness where small sensory nerves were cut, and stiffness of the nearby joint. The pattern is best described in the armpit, after axillary lymph node dissection for breast cancer.
Also known as
Used in a sentence
Staging was completed by axillary lymph node dissection at the time of the mastectomy.
Good to know
Lymphedema of the limb below a cleared area is the characteristic late consequence, and its likelihood rises with the number of nodes removed and with radiation given to the same region.
Word origin
Where “lymph node dissection” comes from
Lymph comes from the Latin lympha, meaning clear water, and dissection from dissecare, to cut apart.