Sentinel node biopsy versus elective lymph node dissection in patients with cutaneous melanoma in a Japanese population

Background In Japan, elective lymph node dissection (ELND) has been the standard treatment for patients with possible nodal melanoma. Sentinel node biopsy (SNB) has now replaced ELND, not only in Japan but also worldwide. The objective of this study was to compare the interim outcomes of SNB and ELND. Methods. A retrospective study was conducted among patients with clinically node-negative disease treated at our institute with either SNB (n = 30) or ELND (n = 72). Results. The background was similar in the two groups. Nodal metastases were found in 40.0% of patients in the SNB group, but in only 26.4% in the ELND group (P = 0.173). The median follow-up was 31.5 months for the SNB group and 82 months for the ELND group. The incidence of locoregional recurrence and distant metastasis in the SNB group was 10.0% and 16.7%, respectively, and for the ELND group the incidence was 5.6% and 31.9%, respectively. The 3-year disease-free survival rate was similar in the two groups (P = 0.280), and the 3-year disease-free survival rates for node-positive patients were also similar in the two groups (P = 0.90), as were the 3-year disease-free survival rates for node-negative patients (P = 0.193). Conclusion. This interim result in a Japanese melanoma population with clinically node-negative disease demonstrated that SNB identified more nodal micrometastases than ELND. This increase in accurate staging likely resulted from the reliable identification of the lymph node field by lymphoscintigraphy, as well as the more detailed pathologic examination of the nodes removed in SNB. It is quite reasonable to perform SNB instead of ELND in this population.