Melanoma Nodal Management in Ontario the Year after the 2012 American Society of Clinical Oncology and Society of Surgical Oncology Guideline

Background: In 2012 in the United States, the American Society of Clinical Oncology and the Society of Surgical Oncology (ASCO/SSO) published a joint guideline about indications for sentinel lymph node biopsy (SLNB) in cutaneous melanoma. The guideline supported completion lymph node dissection (CLND) for all patients with positive sentinel nodes. We examined the rates and predictors of SLNB and CLND for melanoma patients in Ontario (population 13.6 million) after publication of that guideline. Methods: We used the Ontario Cancer Registry to identify patients diagnosed with cutaneous melanoma in 2013. Patient records were linked to prospectively maintained health administrative databases to obtain details for each patient, including surgical procedures. Results: Of the 3298 patients with melanoma identified in Ontario in 2013, 1973 (59.8%) could be analyzed. Most of that group (n = 1227, 62.2%) underwent local excision alone; 746 (37.8%) had a SLNB. The slnb was performed in 13.9%, 67.8%, 62.6%, and 47.2% of patients with T1, T2, T3, and T4 primary melanomas respectively. In multivariate analysis, receipt of slnb was positively associated with younger age (<80 years), higher T stage, and a non-head-and-neck primary. Of the patients who had a SLNB, 136 (18.2%) were found to be node-positive. A CLND was performed in 82 of those patients (60.3%). Conclusions: In Ontario, only two thirds of patients with intermediate-thickness melanomas (T2, T3) underwent SLNB as recommended by the ASCO/SSO guideline. Use of SLNB was less frequent for patients with a head-and-neck primary and higher for younger patients (<80 years). The rate of CLND after a positive SLNB was also low relative to the guideline recommendation.