An 84-year-old man visited our department for further examination of anemia and elevation of tumor marker levels. Colonoscopy revealed a huge circumferential type 3 tumor in the ascending colon. Significant hypoalbuminemia was observed at 1.1 g/dL, and prolonged hypoalbuminemia was considered to be caused by protein-losing gastroenteropathy due to the large tumor. In this case, we performed right hemicolectomy, and performed single-stage anastomosis. The resected specimen showed a huge type 3 lesion with a diameter of 140×120 mm in the ascending colon, which directory invaded to the cecum and ileum. After the operation, there were no particular complications, and albumin levels gradually improved. Although hypoalbuminemia is one of the risks of anastomotic leakage, there are many reports with one-stage anastomosis and with a good course, including our case. Therefore, it was considered necessary to examine each case regarding the surgical procedure.