Question: What are lymph nodes, and what do they do?
Answer: Lymph nodes are filtering stations along the chain of lymph drainage fluid. Lymph drainage fluid drains the excess fluid from all parts of our body; the best example people are aware of of lymph nodes is when they get a strep throat and get swollen glands in their neck. Those glands are really lymph nodes responding to the infection in the throat.
Cancers can spread from any organ to the lymph nodes that drain that area. And the cancers can grow in those lymph nodes and then continue to spread beyond. Spread to a lymph node is a factor which affects the long term outcome of cancer, by denoting that this cancer has the ability to be able to get into a vessel, to be able to spread, and to be able to grow in a site outside the breast.