Analysis of therapeutic strategy changes for patients with melanoma using a national dataset in Japan.

BACKGROUND

Previously, surgical intervention, particularly completion lymph node dissection (CLND), was the standard treatment for sentinel lymph node (SLN)-positive melanoma. However, following the development of adjuvant immune checkpoint inhibitors (ICIs) and targeted therapies (TTs), treatment strategies have shifted toward non-surgical approaches. This shift is also supported by the findings from the Dermatologic Cooperative Oncology Group-SLN Trial and the Multicenter Selective Lymphadenectomy Trial Ⅱ. In this study, using a national dataset in Japan, we investigated trends in melanoma management including CLND and medical cost.

METHODS

We analyzed data from the Japanese Diagnosis Procedure Combination database (2008-2023) to evaluate national trends in melanoma treatment. We identified patients with cutaneous melanoma, and assessed treatment modalities, including SLN biopsy (SLNB), CLND, and adjuvant therapies. The annual proportion of CLND and first-year medical costs after SLNB were also examined.

RESULTS

Among 14,642 patients with melanoma, 874 underwent SLNB. Of these, 170 received ICIs or TTs without undergoing immediate CLND after 2018, and 95 (55.9%) were monitored with ultrasonography. The use of CLND declined steadily after 2017, whereas the average cost during the first year after SLNB increased annually, with a marked rise observed after 2019.

CONCLUSION

The approval of adjuvant therapies and findings from clinical trials may have contributed to the reduction in CLND and rising treatment costs in Japan. As management strategies shift toward non-surgical approaches, more appropriate follow-up strategies will be required. Further research is needed to assess the cost-effectiveness of adjuvant therapies and to optimize follow-up strategies in the Japanese healthcare setting.