Locally advanced endometrial cancer with multiple immune-related adverse events coinciding with the complete response to radiotherapy after immune checkpoint inhibitor therapy: A case report.

We report a case of a 70-year-old female patient with locally advanced endometrial cancer with primary empty sella who developed multiple immune-related adverse events (irAEs), including hypopituitarism coinciding with the complete response to radiotherapy after receiving immune checkpoint inhibitors. A computed tomography scan acquired after a traffic accident led to the discovery of endometrial cancer that had invaded the vulva and primary empty sella. Following adriamycin and cisplatin, pembrolizumab was administered for three cycles. No irAEs were observed during treatment, but the tumor was progressive. The patient underwent radiotherapy for the residual tumor. Four months after the last dose of pembrolizumab, hypopituitarism caused secondary adrenal insufficiency, primary hypothyroidism, and pseudogout at the end of radiotherapy. The tumor later achieved a complete response. In conclusion, radiotherapy after immune checkpoint inhibitor (ICI) therapy is expected to have an antitumor effect by stimulating tumor-specific immunity. However, proper management of irAEs is necessary. Patients with primary empty sella may be prone to pituitary insufficiency induced by ICIs.