Successful treatment of multiple in-transit melanomas on the leg with intensity-modulated radiotherapy and immune checkpoint inhibitors: Report of two cases.

Because the efficacy rates of monotherapy with immune checkpoint inhibitors such as nivolumab or ipilimumab are not sufficient, to enhance the antitumor effects of these reagents is of great interest among dermato-oncologists. In this report, we describe two cases of multiple in-transit metastatic melanomas on the leg successfully treated with intensity-modulated radiotherapy (IMRT) using a CyberKnife in combination with ipilimumab or nivolumab. Our cases suggested that IMRT could enhance the antitumor effects of immune checkpoint inhibitors in patients with multiple in-transit melanomas.