Abscopal Effect in a Patient With Metastatic Melanoma Receiving Hypofractionated Radiation Therapy and Dual Immune Checkpoint Inhibition: A Case Report.

Concurrent with the increasing utilization of immune checkpoint inhibitors (ICIs) in melanoma, there has been renewed interest in understanding the potential interplay between radiation therapy (RT) and the immune system. One such phenomenon is the abscopal effect, where localized treatments, such as RT, not only shrink the targeted tumor but also induce shrinkage of untreated tumors elsewhere in the body. Here, we report a case of an abscopal effect in a 63-year-old patient with metastatic melanoma who was progressing on first-line dual ICI therapy but experienced a rapid and durable systemic response following the administration of hypofractionated palliative RT to a large primary melanoma skin tumor.