[A Case of Transverse Colon Cancer in Which Long-Term Chemotherapy Was Performed after Palliative Colonic Stent Placement].

We report a case involving a 76-year-old woman with transverse colon cancer undergoing long-term chemotherapy following palliative colonic stent placement. She visited our hospital with a diagnosis of colonic obstruction. Her abdomen was evidently distended and tender. CT revealed the apple core sign in the transverse colon-hepatic flexure area, and then bowel obstruction. The disseminated lesion occluded the superior mesenteric vein. Multiple masses were found on both lungs; a single tumor was detected in liver S6. Hence, we diagnosed her with unresectable obstructive transverse colon cancer. A colonic stent was inserted to remove the obstruction. Because primary tumor resection was rendered impossible, mFOLFOX6 was initiated with the colonic stent intact. After 5 courses, CT revealed that the liver metastasis disappeared, and lung metastases exhibited SD of a therapeutic effect. She further received 5 courses of mFOLFOX6 and 20 courses of maintenance therapy using FU. However, single liver metastasis recurred, exhibiting PD of a therapeutic effect. Histological diagnosis of liver metastasis was a consistent finding due to metastatic colorectal cancer; RAS mutation was not detected. Currently, 2 years after the diagnosis, FOLFIRI and panitumumab are being administered as the second-line treatment, with no colonic stentrelated complications.