Lymph node metastasis

Cancer cells that generate distant metastases travel from the primary tumor through the blood and lymphatic system. In the latter case, they penetrate the lymphatic vessels and, transported by lymph, reach the lymph node closest to the tumor, which in the clinic is called the sentinel node. Most of the cells that reach it are destroyed, but it is possible that some of them survive and can reproduce until they form a lymph node metastasis and from there spread to other nodes following the order of the lymphatic system, causing successive metastases ganglionic In fact, in certain types of cancer this type of metastasis, as well as the number of nodes affected, is an important prognostic factor, since it can predict the existence of other distant metastases that affect other organs. Also, the higher the number of nodes affected, the more advanced the primary cancer.

Occasionally, inflammation of a lymph node may be the first sign of the existence of a cancer that begins to metastasize. In fact, nodal metastases are the most frequent. Thus, for example, a breast cancer that affects the upper chest usually produces a metastasis in the nodes located in the armpit. In this case, and also in melanoma, a sentinel node biopsy is usually done. If this provides a positive result, then the map of the tumor’s lymphatic drainage system can be determined by injecting a radioactive contrast, which will provide a radiological image of the tumor, although there is no determining pattern of lymphatic drainage that allow to establish with certainty the existence or not of metastases in the different nodes, since it varies from one patient to another. This means that in 30% of cases it is not possible to establish the existence or not of a lymph node metastasis. That is why, when the primary tumor is removed by surgery, the sentinel node is also removed and biopsies are performed on the other nodes of the drainage chain to determine how many of them are affected. As already said, the higher the number, the worse the prognosis and the greater the chances of other distant metastases in other organs or tissues of the body.