Immunotherapy for orbital squamous cell carcinoma

Purpose: To evaluate the demographics, clinical features and response of orbital squamous cell carcinoma treated with immunotherapy in an Australian and New Zealand cohort. Methods: This is a multi-institutional, retrospective case series. Data was collected on patient demographics, clinical presentation, imaging findings, treatment course and outcomes. Details of post-immunotherapy surgical interventions were documented along with their histological findings. Results: Ten patients were included. All patients had invasive orbital squamous cell carcinoma. Perineural spread was present in six patients. Seven patients received Cemiplimab, while three patients received Pembrolizumab. No patients experienced side effects requiring cessation of immunotherapy. One patient died during follow up due to an unrelated cause. Eight (80%) patients had measurable radiological response, whereas one (10%) patient had progressive disease. Two patients had orbital exenteration: one due to progressive disease and one due to residual disease on MRI. One patient had orbital mapping biopsies. Two (66%) patients that had tissue analysis following immunotherapy showed complete pathologic response. Conclusion: Our findings support the emerging role of immunotherapy in the management of invasive orbital squamous cell carcinoma.