Metastatic lung adenocarcinoma: complete remission on nivolumab complicated by immune-mediated diabetes

What happened, in summary

This 57-year-old man, a heavy smoker, came to the emergency department in March 2017 with persistent cough, night fever, and weight loss. CT imaging showed a 40 × 80 mm mass in the superior left lung, staged cT2N0M0, Stage II, and biopsy identified pulmonary adenocarcinoma. The mass was resected, and pathology confirmed EGFR-negative and ALK-negative lung adenocarcinoma. Four weeks after surgery, he developed blurred vision, headache, and ataxia. Brain CT showed 2 lesions, one in the cerebellum and one in the occipital lobe, so the disease was treated as Stage IV lung adenocarcinoma. He received whole-brain radiation therapy, then pemetrexed plus cisplatin every 3 weeks for 6 cycles, followed by pemetrexed maintenance. In June 2018, CT showed liver and left occipital metastases. The brain metastases were resected, and nivolumab 240 mg every 2 weeks was started. He remained on nivolumab for almost 4 years with no disease progression and ECOG performance status 0. In March 2022, he tested positive for SARS-CoV-2 during screening but had no symptoms. After his next nivolumab dose, he developed severe fatigue, hyperglycemia of 585 mg/dL, electrolyte abnormalities, elevated liver enzymes, undetectable C-peptide, and negative diabetes autoantibodies. Nivolumab was permanently stopped, and he was treated with intravenous insulin followed by basal-bolus insulin. Imaging in May 2022 showed complete remission, and scans in July 2022, November 2022, April 2023, and October 2023 continued to show no evidence of cancer. As of March 2025, he had excellent long-term ECOG performance status and well-controlled diabetes on basal-bolus insulin therapy.