| Axillary lymph nodes | |
|---|---|
 Lymphatics of the breast and the axillary glands | |
| |
| Details | |
| System | Lymphatic system |
| Drains from | Axilla |
| Identifiers | |
| Latin | nodi lymphoidei axillares |
| TA98 | A13.3.01.002 |
| TA2 | 5236 |
| FMA | 12771 |
| Anatomical terminology | |
Theaxillary lymph nodes orarmpit lymph nodes arelymph nodes in the humanarmpit. Between 20 and 49 in number, they drainlymph vessels from the lateral quadrants of the breast, the superficial lymph vessels from thin walls of the chest and theabdomen above the level of the navel, and the vessels from the upper limb. They are divided in several groups according to their location in the armpit. These lymph nodes are clinically significant inbreast cancer, andmetastases from the breast to the axillary lymph nodes are considered in thestaging of the disease.[1]
The axillary lymph nodes are arranged in six groups:[2]
The apical nodes drain into thesubclavian lymph trunk. On the left side, this trunk drains into thethoracic duct; on the right side, it drains into theright lymphatic duct. Alternatively, the lymph trunks may drain directly into one of the large veins at the root of the neck.[3]
About 75% oflymph from the breasts drains into the axillary lymph nodes, making them important in the diagnosis andstaging of breast cancer. A doctor will usually refer a patient to a surgeon to have an axillarylymph node dissection to see if the cancer cells have been trapped in the nodes. For clinical stages I and II breast cancer, axillary lymph node dissection should only be performed after first attempting sentinel node biopsy.[4]
If cancer cells are found in the nodes, it increases the risk of metastatic breast cancer. Another method of determining breast cancer spread is to perform an endoscopic axillary sentinelnode biopsy. This involves injecting a dye into the breast lump and seeing which node it first spread to (thesentinel node). This node is then removed and examined. If there is no cancer present, it is assumed the cancer has not spread to the other lymph nodes. This procedure is often less invasive and less damaging than the axillary lymph node dissection. The estimated risk of lymphedema following sentinel lymph node procedure is less than 3%.[citation needed] The approximate risk of lymphedema following axillary lymph node dissection is 10-15% and this can slightly increase with the addition of radiotherapy and chemotherapy to as much as 20-25% depending on the extent of dissection, extent of radiotherapy fields, and history of chemotherapy.[citation needed]
OnCT scan orMRI, axillarylymphadenopathy can be defined as solid nodes measuring more than 1.5 cm without fatty hilum.[5] Lymph nodes may be normal up to 3 cm if consisting largely of fat.[5]
Axillary lymph nodes are included within the standard tangential fields in radiotherapy for breast cancer. In the case of comprehensive nodal irradiation, which includes axillary levels I, II, and III, as well as a supraclavicular lymph node field, there is a risk of damage to brachial plexus. The risk is estimated to be less than 5% as the brachial plexus radiation tolerance according to (Emami 1991) is 60 Gy in standard fractionation (2 Gy per fraction).[citation needed] A common prescribed dose for breast cancer with comprehensive nodal fields would be 50 Gy in 25 fractions with a boost planned to the lumpectomy cavity in the breast or scar on the chest wall if it is a mastectomy. If brachial plexopathy does occur, it is generally a late effect and may not manifest itself until 10 or 15 years later, and usually presents with slight painless muscular atrophy.
Malignancies in the gastrointestinal system likegastric cancer can metastasize to the left axillary lymph node which is called "Irish’s node".[6]
