Case reports in oncology
Suspected Abscopal-Pattern Response following Radiotherapy in a Patient Receiving Cemiplimab for Advanced Cutaneous Squamous Cell Carcinoma: A Case Report
By Faunce WE, Agostino N and Foster B.
Abstract
Introduction
The abscopal effect is a rare phenomenon in which localized radiotherapy leads to regression of distant, nonirradiated tumors through systemic immune activation, often enhanced by immune checkpoint inhibitors. It is infrequently reported in cutaneous squamous cell carcinoma and even less so in immunocompromised patients. We report a case of head and neck cutaneous squamous cell carcinoma in an immunocompromised patient treated with PD-1 inhibition and localized radiotherapy, in which a distant untreated lesion regressed, consistent with a suspected abscopal response.
Case presentation
An 88-year-old immunocompromised male with a history of acute myeloid leukemia developed a biopsy-proven well-differentiated cutaneous squamous cell carcinoma of the head and a separate clinically suspicious scalp lesion concerning for malignancy. He was treated with systemic cemiplimab and subsequently received localized radiotherapy (30 Gy in 10 fractions) to a left postauricular lesion, while a separate left scalp lesion was outside the radiation field. Following completion of radiotherapy, the treated lesion demonstrated complete clinical response. Notably, the untreated scalp lesion also showed marked regression within weeks, consistent with an abscopal-pattern response. This occurred in the setting of chronic immunosuppression related to his underlying hematologic malignancy and its treatment.