Postoperative immune-related adverse events after conversion surgery following induction immune checkpoint inhibitor-combined chemotherapy in patients with unresectable esophagogastric junction carcinoma: A report of two cases

Background An increasing number of patients are undergoing conversion surgery owing to the rising popularity of relatively strong regimens such as immune checkpoint inhibitor (ICI)-combined chemotherapy for the treatment of unresectable esophageal or esophagogastric junction (EGJ) cancer. However, the perioperative safety of conversion surgery after ICI combined with chemotherapy remains unclear. We report two cases of postoperative immune-related adverse events (irAEs) in patients who underwent conversion surgery after the induction of ICI-combined chemotherapy. Case presentations Case 1: A patient with unresectable EGJ adenocarcinoma and para-abdominal aortic lymph node (LN) metastasis developed adrenal insufficiency after four courses of nivolumab + S1 + oxaliplatin (Nivo + SOX) therapy. As significant tumor shrinkage was observed, conversion surgery was performed. While the postoperative course was uneventful, two months after surgery, hypothyroidism developed and was determined to be an irAE. Thyroid hormone replacement therapy was administered and the symptoms improved. Case 2: A patient with EGJ adenocarcinoma and extensive metastasis to mediastinal, supraclavicular, and para-aortic LNs, along with aortic invasion, also received four cycles of Nivo + SOX. Hypothyroidism developed during treatment and was managed with thyroid hormone replacement therapy. Following notable tumor regression, the patient underwent conversion surgery. The patient’s postoperative course was uneventful and was discharged. However, one month after surgery, the patient was readmitted with severe respiratory distress and was diagnosed with interstitial pneumonia. Intensive care with extracorporeal membrane oxygenation (ECMO) was initiated following steroid and endoxan pulse therapy, but the patient died four months after surgery. Conclusions The risk of irAEs should always be considered in patients receiving ICIs, even after conversion surgery. This condition should be differentiated from complications of esophagectomy and managed promptly.