One of the most important prognostic factors in patients with early-stage melanoma is the presence of metastasis to regional nodes. Determining which patients have nodal metastases and who may benefit from resection of involved regional lymph nodes is of key importance. Sentinel lymph node biopsy (SLNB) is a minimally invasive surgical technique that involves removal of the node(s) most likely to demonstrate metastases (the “sentinel” node) from melanoma. When cancer is found, the remaining nodes in that area are also at risk for metastases.
In most cases, no cancer is detected in the sentinel node, allowing patients to avoid the pain, discomfort, expense, and side effects of unnecessary procedures or therapies. In an effort to clarify which patients should undergo SLNB, the American Society of Clinical Oncology and the Society for Surgical Oncology published clinical practice guidelines in the Journal of Clinical Oncology.
Key Recommendations for Melanoma
Recommendations were made based on the three main stages of melanoma:
1. Intermediate-thickness melanomas: SLNB is recommended for patients with cutaneous melanomas with Breslow thickness of 1 to 4 mm at any anatomic site.
2. Thick melanomas: SLNB may be used for staging purposes and to facilitate regional disease control in patients with melanomas greater than 4 mm in Breslow thickness.
3. Thin melanomas: There is insufficient evidence to support routine SLNB for patients with melanomas that are less than 1 mm in Breslow thickness, although it may be considered in selected high-risk patients.
It’s recommended that complete lymph node dissection be performed for all patients with a positive SLNB. If sentinel nodes are positive, additional nodes should be removed for complete staging of the disease and prevention of further metastases. Use of this procedure in thin melanomas is controversial because benefits have been unproven in clinical trials and clinical practice. Studies show that the rate of positive sentinel node detection in this group is quite low. Clinicians must determine if putting patients with thin melanomas through an additional procedure will have a positive impact for them when the benefits are unclear.
“Clinicians must determine if putting patients with thin melanomas through an additional procedure—with additional risks and costs—will have a positive impact for them when the benefits are unclear.”
Implications on Treatment Decisions
It’s possible that payers will review these guidelines and determine that they will only support using SLNB based on guideline-recommended indications. Clinicians who treat patients with melanoma should be aware of the recommendations and adapt their practice accordingly. The guidelines also offer assistance in deciding whether or not patients should be referred to surgical oncologists for consideration of the procedure. Considering that the guideline was strictly evidence-based, it may differ slightly from other guideline recommendations based solely on consensus or expert opinion. Physicians should think about the standard of care; if standards aren’t being adhered to, patients may benefit from entering a clinical trial.
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