Sentinel node biopsy for thin melanomas: which patients should be considered?

BACKGROUND As the incidence of melanoma increases, thin melanomas are being diagnosed at an increasingly frequent rate. Currently available prognostic factors are limited in their ability to reliably discriminate which patients will manifest regional nodal metastasis and would be identified early through sentinel node biopsy. METHODS We summarized our experience with sentinel node biopsy for patients with cutaneous melanomas less than 1.00 mm in Breslow thickness, with evaluation of Clark level as a predictor of positive sentinel node metastasis. RESULTS Among the 409 patients identified, micrometastases were found in the sentinel node in 20 patients, for an overall incidence of nodal progression of 4.9%. A total of 252 (62%) were Clark level II or III (11 of whom had a positive sentinel node) and 157 (38%) were Clark level IV (9 of whom had a positive sentinel node). We reviewed the literature to identify reliable indicators that might be helpful in determining which patients with "thin melanomas" would be likely to manifest regional progression to warrant routinely undergoing a preoperative lymphoscintigraphy followed by a sentinel node biopsy. CONCLUSIONS Based on available data, patients with melanomas between 0.75 and 1.00 mm are appropriate candidates to be considered for sentinel node biopsy after discussing the likelihood of finding evidence of nodal progression, the risks of sentinel node biopsy (including the risk of a false-negative result), and the lack of proven survival benefit from any form of surgical nodal staging.