Lung Cancer and Immunotherapy: When the Immune System Becomes the New Challenge

Abstract

Pembrolizumab is an immune checkpoint inhibitor. With the introduction of this therapeutic class, the adverse- event profile of antineoplastic therapy has changed, creating new challenges in the longitudinal management of patients with cancer.

We report the case of a 75- year- old man with metastatic lung adenocarcinoma (PD- L1 expression 90%90% KRAS G12C mutation) who started treatment with pembrolizumab 2mg/kg2mg/kg every three weeks. Nine months later, he presented with acute hyperglycemia (939 mg/dL) without ketoacidosis, interpreted as autoimmune diabetes secondary to immunotherapy, requiring intensive insulin therapy. Subsequently, he developed bilateral immune- mediated keratitis, treated with artificial tears, topical corticosteroids and antibiotics, as well as systemic corticosteroids. After clinical stabilization, Pembrolizumab therapy was reinstated, with adequate glycemic control and controlled ocular symptoms.

This case illustrates multisystem immune- mediated adverse reactions associated with pembrolizumab and the importance of multidisciplinary management for the success of cancer therapy and improvement of patients' quality of life.