2019 Volume 53 Issue 6 Pages 343-348
A man in his 70s underwent pancreaticoduodenectomy due to pancreatic head cancer six years ago. He received S‐1 for 1 year as postoperative adjuvant chemotherapy. A right lung tumor was found four years later. He underwent partial resection of the right lung by video‐assisted thoracic surgery for suspected primary or metastatic lung cancer. He was diagnosed postoperatively with lung metastasis of pancreatic cancer. He was administered S‐1 again, but his compliance was poor. He underwent partial resection of the right lung by video‐assisted thoracic surgery due to pneumothorax the following year. A sudden increase in his serum CA19‐9 level was noted in April six years later. Although no abnormality was observed on plain or contrast‐enhanced CT imaging of the chest and abdomen, he received single‐agent chemotherapy with gemcitabine in July of the same year under the strong suspicion of pancreatic cancer recurrence. Following his complaint of thirst during chemotherapy, laboratory tests revealed hyperglycemia, indicated by markedly high levels of glucose at 510 mg/dL and HbA1c at 14.3％．After he was hospitalized for diabetes mellitus and received intensive insulin therapy, his serum CA19‐9 level immediately normalized. Hyperglycemia is a known cause of high serum CA19‐9, but CA19‐9 may also increase due to secondary diabetes following pancreatectomy. However, six years had passed since the operation, and his blood glucose and HbA1c levels had not been measured recently. This case highlighted the importance of maintaining the continuity of blood glucose management after pancreaticoduodenectomy．
