Neoadjuvant Cemiplimab Followed by Radiation for Locally Advanced, Unresectable Cutaneous Squamous Cell Carcinoma: A Case Report

Background: Cutaneous squamous cell carcinoma (cSCC) is highly treatable with early detection and surgical resection. However, patients with locally advanced and metastatic disease have poor outcomes with surgery alone and require additional treatment. Neoadjuvant cemiplimab followed by surgery has shown promising results, but there is little evidence to the efficacy of cemiplimab in patients who are not amenable to surgical resection.Case: A 60 year old woman with a pertinent medical history of COPD, Hepatitis C, and tobacco abuse presented to the emergency department with a 12 cm fungating mass on the right forearm. Skin biopsy revealed cSCC and imaging studies showed invasion into the brachioradialis muscle. The patient was initially planned for 4 cycles of neoadjuvant cemiplimab followed by surgery and radiation, but socioeconomic issues pervaded, and surgical resection was inevitably not recommended. The patient instead was treated with neoadjuvant cemiplimab for 9 cycles followed by radiation 60 Gy over 30 fractions. Partial clinical response was seen after 2 cycles of cemiplimab, and a complete clinical response was seen after completion of radiotherapy. Complete clinical response was maintained at 1.5-year follow-up with only mild sensory deficits over the original site of the tumor.Conclusion: Locally advanced cSCC that is not amenable to surgical excision can be definitively treated with cemiplimab followed by radiotherapy with long term response and minimal deficits from treatment.