Sentinel Lymph Node Biopsy and Management of Regional Lymph Nodes in Melanoma: American Society of Clinical Oncology and Society of Surgical Oncology Clinical Practice Guideline Update Summary

In 2017, approximately 87,100 new cases of melanoma will be diagnosed and over 9,730 deaths due to melanoma are expected in the United States.1 Although melanoma only accounts for approximately 1% of skin cancers, it is responsible for the majority of skin cancer morbidity and mortality, and the incidence has been increasing over the past 30 years.2 The mainstay of melanoma treatment options continues to be resection (local excision of the tumor with wide margins), but strategies for management of regional and systemic disease have evolved considerably over the past two decades. Biopsy of the sentinel lymph node (SLN), the first node in a group of nodes to be affected by metastatic cancer, has become an established procedure for identifying nodal metastases. Knowledge of regional lymph node status helps to determine prognosis, facilitates strategies for regional disease control, and aids in the selection of patients who may benefit from adjuvant therapy.3 SLN biopsy is a minimally invasive procedure that accurately detects nodal metastases in patients with clinically occult disease. In 2009, the 7th edition of the American Joint Committee on Cancer staging system formally recognized the prognostic value of micrometastases.4,5 Five-year survival rates range from 70% for patients with one SLN with micrometastatic disease to 39% for patients with four or more involved nodes or with nodes that are extensively involved (Gershenwald et al, manuscript submitted for publication). When the previous version of this guideline was published in 2012, SLN biopsy was an established procedure for newly diagnosed patients with primary cutaneous melanoma; however, there was a need to develop and formalize guideline recommendations for its indications in specific subpopulations. Because the risk of lymph node involvement varies by thickness of melanoma, recommendations were stratified by this variable.6,7 For the 2012 guidelines, the joint ASCO-Society of Surgical Oncology guideline panel concluded that the potential benefits of SLN biopsy outweighed the risk of harm for patients with intermediate-thickness melanoma.6,7 SLN biopsy was also recommended as an option for thick melanomas for staging purposes and to facilitate regional disease control. SLN biopsy was not routinely recommended for patients with thin melanomas; however, it could be considered in patients with higher risk features, which were previously defined as 0.75 to 0.99 mm Breslow thickness with ulceration and/or mitotic rate ≥ 1/mm2.2 A completion lymph node dissection was recommended for all patients