Axillary lymph nodes
|Axillary lymph nodes|
Lymphatics of the breast and the axillary glands
2. Axillary lymphatic plexus
4. Cubital lymph nodes (not part of the lymph node drainage of the breast)
5. Superficial axillary (low axillary)
6. Deep axillary lymph nodes
7. Brachial axillary lymph nodes
8. Interpectoral axillary lymph nodes (Rotter nodes)
10. Paramammary or intramammary lymph nodes
11. Parasternal lymph nodes (internal mammary nodes)
|Latin||Nodi lymphoidei axillares|
The axillary or armpit lymph nodes drain lymph from the arms, breast, chest wall and upper abdomen. They are large, vary from twenty to thirty in number, and may be arranged in the following groups:
- brachial lymph nodes (or "lateral", or "humeral")
- pectoral axillary lymph nodes (or "anterior")
- subscapular axillary lymph nodes (or "posterior")
- apical lymph nodes (or "medial" or "subclavicular")
About 75% of lymph from the breasts drains into the axillary lymph nodes, making them important in the diagnosis of breast cancer. A doctor will usually refer a patient to a surgeon to have an axillary lymph 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.
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 sentinel node biopsy. This involves injecting a dye into the breast lump and seeing which node it first spread to (the sentinel 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%. 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.
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). 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.
- American College of Surgeons (September 2013), "Five Things Physicians and Patients Should Question", Choosing Wisely: an initiative of the ABIM Foundation (American College of Surgeons), retrieved 2 January 2013, which cites various primary research studies.
- Image at breastcancer.org
- lesson3axillarylymphnodes at The Anatomy Lesson by Wesley Norman (Georgetown University)