Results from a recent article published in the British Journal of Surgery suggest that breast cancer patients with a negative sentinel node biopsy (SNB) may safely avoid additional axillary dissection.
For over 30 years, the standard of practice for breast cancer staging has included the removal of axillary (under the arm) lymph nodes to aid in determining the spread of cancer in the body. If cancer spreads from its site of origin, it is thought to spread first to the lymph nodes that initially collect the excess lymph fluid from that area (sentinel lymph nodes). With current standard staging procedures, axillary lymph nodes are removed during surgery and are tested to determine if they contain breast cancer cells. The presence or absence of cancer cells in axillary lymph nodes is an essential factor in defining optimal treatment strategies following surgery. Women who have cancer cells present in their axillary lymph nodes are thought to have cancer that has spread and therefore require adjuvant systemic (full-body) therapy. Conversely, women without cancer cells in their axillary lymph nodes are thought to have only localized breast cancer and may require less aggressive adjuvant therapy and observation.
Unfortunately, the removal of axillary lymph nodes (approximately 25 nodes) is associated with chronic side effects including pain, infection, limited shoulder motion, numbness and lymphedema (swelling of the arm due to an accumulation of lymph fluid). Since these complications can become debilitating, the strategy of sentinel lymph node dissection is currently being evaluated and refined. This strategy incorporates the removal of only the sentinel lymph node(s) for biopsy (SNB) to determine the extent of cancer spread. Because the sentinel lymph node(s) (SLN) receives initial drainage from the cancer, it has the highest probability of containing cancer cells if the cancer has spread. Therefore, the removal of other axillary lymph nodes may be unnecessary if the SNB is negative. If accurate, this practice could eliminate the need for standard axillary node dissection and its complications.
The precision in correctly identifying the SLN is imperative in order for this procedure to provide accurate results. Currently, there are two methods that are commonly used together: 1) injections of blue dye in the area immediately encompassing the cancer, 2) injections of a radioactive substance in the area immediately encompassing the cancer. The injections are administered prior to surgery. During surgery, the surgeon identifies the node(s) containing either the blue dye (through direct visualization) or the radioactive substance (through a hand-held probe that detects radioactivity), indicating the collection of drainage from the cancer. The node(s) that collects the injected substances is determined to be the SLN and is subsequently removed for a SNB.
Researchers in Britain recently conducted a study evaluating the safety of avoiding additional axillary dissection in breast cancer patients who had a negative SNB. One hundred breast cancer patients that had a negative SNB were observed for 1 to 3 years for local recurrence, distant metastases, overall survival, and functional impairment of the involved arm or shoulder. Only 1 of the 100 patients had any axillary recurrence. Twelve of the 94 patients assessed for functional impairment reported mild disabilities and no patient developed lymphedema.
These results provide more encouraging evidence for the standardization of SNB without additional axillary dissection for negative SNB cases. They also show promise that future breast cancer patients with negative SNB may be able to avoid unnecessary procedures and potential complication like lymphedema associated with axillary dissection. However, since SLN dissection is a relatively new clinical procedure, the experience of a physician in performing this procedure is crucial in providing accurate results. It is imperative that patients who decide to undergo SLN dissection ask their physician how accurate the procedure is in their institution.
Patients with breast cancer that have a negative SNB may wish to speak with their physician about the risks and benefits of excluding additional axillary dissection or other novel therapeutic approaches. Two sources of information regarding ongoing clinical trials include comprehensive, easy-to-use listing services provided by the National Cancer Institute (cancer.gov) andwww.eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients. (British Journal of Surgery, Vol 88, No 12, pp 1639-1643, 2001)
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