Axillary surgery is a procedure to remove lymph nodes in the armpit (axilla). These nodes are examined to determine whether cancer cells have spread to the lymphatic system.
Sentinel lymph node biopsy involves the removal of only those nodes identified to be at highest risk of containing cancer cells. This procedure is provided as an alternative to axillary lymph node dissection which removes a larger collection of lymph nodes and has a higher risk of arm problems such as lymphoedema (obstruction of lymphatic system causing fluid retention and tissue swelling).
Guidelines for use of sentinel lymph node biopsy
Guidelines released by Australia's National Breast and Ovarian Cancer Centre (now part of Cancer Australia) in 2008 recommend sentinel lymph node biopsy be offered as an alternative for axillary lymph node dissection where breast cancer was restricted to one tumour of not more than 3cm in size. If the node or nodes removed were found to contain cancer cells, it was recommended that an axillary lymph node dissection was also performed.
National guidelines in New Zealand make similar recommendations.
Increase in use of sentinel lymph node biopsy over time
For patients with tumours of 3cm or less, the proportion being initially managed with sentinel lymph node biopsy increased from 18.8% in 1999 to 77.6% in 2010. Sentinel lymph node biopsy became more common than axillary lymph node dissection for these patients in 2004.
For patients with at least one tumour over 3cm, the proportion being initially managed with sentinel lymph node biopsy increased from 11.5% in 1999 to 44.6% in 2010. Sentinel lymph node biopsy became more common than axillary lymph node dissection for these patients in 2009.
Factors affecting choice of sentinel lymph node biopsy over sentinel lymph node dissection
Of those patients who received axillary surgery, the more invasive sentinel lymph node dissection procedure was more likely to be chosen if:
- age was over 70
- no private health insurance
- surgeon treating less cases of early breast cancer per year
- treatment occurred in an inner or outer regional centre.
Performing a second axillary surgery after sentinel lymph node biopsy
During the study period, the proportion of patients with tumours of 3cm or less undergoing a second axillary procedure after a sentinel lymph node biopsy dropped from 91.8% of patients to 19.5%. The proportion of patients with at least one tumour over 3cm undergoing a second procedure declined from 91.8% to 45.1%.
Where a second axillary surgery is performed, it is increasingly common to have it performed on a different day than the original surgery.