Description of Treatment/Procedure

The most important prognostic factor for patients with breast cancer is the tumor status of the regional lymph nodes draining the primary tumor site. Patients with axillary metastases are more likely to develop systemic metastases and die of their disease than those with pathologically negative nodes. Determination of nodal status by random sampling or by palpation has been found to be inadequate; lymph node dissection (LND) is the standard of care. LND is associated with potential long-term morbidities including lymphedema, nerve injury, limited range of motion, pain, and weakness and is an unnecessary procedure in the 70-80% of breast cancer patients who are node-negative. Lymphatic mapping with sentinel lymph node biopsy (SLNB) has been proposed as a method to determine the nodal status of the axillary region. Ideally, the tumor status of the sentinel node (SN) would be reflective of the tumor status of the entire axillary region and therefore would indicate the need for LND.

Committee Summary

With regard to lymphatic mapping with SLNB, the ICSI Technology Assessment Committee finds the following:

1. For axillary staging, SLNB has become an acceptable alternative to axillary lymph node dissection (LND) in patients with invasive breast cancer. (Conclusion Grade II) SLNB would be appropriate for patients with solitary tumors less than 5 cm and a clinically negative axilla. SLNB should be performed by an experienced surgeon. The literature would suggest that to achieve an acceptable identification rate (>=85%) and false negative rate (<=5%), at least 10 to 20 cases of SLNB followed by LND should be performed.
   
2. At present, no long term survival data are available. Two national, multicenter, randomized trials designed to evaluate survival are underway.
   
3. The procedure is safe; reports of procedure-related complications are rare, adverse effects are minimal, and exposure levels to radioactive materials (when used) have been found to be acceptable.
   
4. There is a learning curve for locating the sentinel node(s) (SN). A protocol that uses both vital blue dye and a radioactive tracer is typically easier to learn and results in lower false negative rates.
   
5. The approach requires a multidisciplinary team including surgeons, radiologists (nuclear radiologists if radioactive materials are to be used), pathologists, and medical or radiation oncologists and, if radioactive materials are used, must be done in facilities adequately equipped to dispose of those materials.
   
6. It appears that serial sectioning with immunohistochemical (IHC) staining detects more occult nodal metastases. Clinical trials are underway to determine the significance of IHC positive cells in lymph nodes.