Immune-Related Adverse Events in a Patient Treated with Pembrolizumab: A Case Report from the Point of View of a Geriatrician.

We report the case of a 78-year-old female patient who received palliative immunotherapy with pembrolizumab and lenvatinib as a treatment of pulmonary and osseous metastatic endometrial carcinoma. Under this therapy, the patient developed dysphagia, thyroiditis with hypothyroidism, myositis, and myocarditis, which required, due to third-degree AV block, the installation of a pacemaker. The patient received high-dose cortisone therapy, a thyroid hormone substitution, and pyridostigmine for symptom control. With this therapy, we saw a significant but not complete regression of symptoms. Ultimately, we could discharge the patient home for an outpatient treatment. The case report is followed by a discussion of the management of immune-related adverse events (irAEs) during pembrolizumab therapy from a geriatric perspective. Elderly patients on pembrolizumab therapy require close monitoring for irAEs, which can present atypically or without symptoms and may be fatal. Non-invasive diagnostics and minimizing hospital stays are essential to preserve the fitness of this vulnerable population.