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Sentinel lymph node biopsy for thin melanoma‐con

When sentinel lymph node biopsy (SLNB) for the regional staging of melanoma was first introduced, it was recommended for any patient with a melanoma between 1.0 and 4.0 mm in Breslow thickness. Patients with thin melanomas were not felt to have a sufficiently high risk to warrant the additional cost and morbidity of the procedure. As experience grew, several retrospective series identified risk factors beyond Breslow thickness that were associated with an increased risk of regional metastases, and should therefore prompt consideration of SLN biopsy for patients with melanomas shy of 1.0 mm (generally considered to be 0.76–0.99 mm). These were quite varied and included Clark level IV or V, ulceration, mitotic rate (MR), angiolymphatic invasion, and the age of the patient (younger patients having a higher rate of SLN metastases than their older counterparts), with the last three being the most consistent. SLN biopsy is also often recommended for patients with thin melanoma who have significant regression or a positive deep margin, as the true Breslow thickness is often unknown. When the most recent version of the AJCC staging system for melanoma was released [1], one of the most significant changes was the classification of stage T1b as any melanoma 1.00 mm with ulceration or a MR of 1/mm 2 . Despite the caveat that ‘‘the AJCC Melanoma Staging Database did not contain sufficient data to assess risk of occult nodal micrometastases in this population,’’ many surgeons have advocated extending the indications for SLNB to include any T1b melanoma. This would include any melanoma <0.76 mm with a MR of at least 1/mm 2 . However, this is not an accurate interpretation of the data. One might assume that the majority of these patients recur regionally first, then distally, and survival may be impacted because of regional recurrence. However, recent data suggests that this is not true; T1b status does not impact regional recurrence but does increase the likelihood of distant recurrence [2]. These data support the new AJCC staging system for prognostication, but not for selection for SLNB. So should SLN biopsy be performed for patients with T1b melanoma? As with most debates in medicine, most of the controversy centers on the semantics. Are there some patients with T1b melanomas who require SLN biopsy? Absolutely, this has never been in debate, as discussed above. So the real controversy centers on two questions: