Impact of the changes in the completion lymph node dissection criteria and approval of adjuvant therapies on the real-world outcomes of Japanese stage III melanoma patients

Background Completion lymph node dissection (CLND) has long been the standard treatment for stage III melanomas identified as metastasis on the sentinel node (SN-positive). Two major changes occurred in 2017 and 2018, the change in the CLND criteria for SN-positive patients and the approval of several adjuvant therapies could revolutionize such management approach. However, their effects have not been fully investigated on the real-world outcomes of stage III melanoma patients. Therefore, we investigated the impact of these changes on the prognosis of Japanese stage III melanoma patients. Methods Totally, 119 stage III, SN-positive melanoma patients were included. They were categorized into those diagnosed as SN-positive between January 2015 and June 2017 (pre-June 2017 group) and between July 2017 and December 2019 (post-July 2017 group). Recurrence-free survival (RFS), overall survival, and prognostic factors were analyzed. Results The frequency of patients who received CLND was significantly higher in the pre-June 2017 group ( p = 0.001), and those who received adjuvant therapy were significantly higher in the post-July 2017 group ( p