432. A CASE OF ADVANCED ESOPHAGEAL CARCINOSARCOMA DIAGNOSED LATE DUE TO SEVERE STENOSIS AFTER CHEMORADIOTHERAPY

Radiochemotherapy (CRT) is one of the curative treatment options next to surgery in the treatment of esophageal squamous cell carcinoma. However, CRT may cause esophageal stenosis or obstruction during the healing process. Therefore, in such cases, follow up of early recurrence detection becomes an issue for those patients. We report a case of severe stenosis after CRT, in which recurrence could not detected until advanced cancer developed on the anal side of stenosis. The case is a 73-year-old male. He was diagnosed with upper thoracic esophageal cancer (T4N2M0StageIVa) and had undergone radical chemoradiotherapy 5 years ago. The treatment effect achieved a complete response, but the primary tumor site caused severe esophageal stenosis. Therefore, biannual CT follow up had been done instead of endoscopic follow up. During follow-up, CT revealed a new neoplastic lesion in the lower thoracic esophagus, and endoscopy inserted through a gastrostomy revealed a bulky tumor on the anorectal side of the stenotic lesion. Biopsy revealed carcinosarcoma and robot-assisted thoracoscopic esophagectomy was performed. Malignant neoplasms can be developed not only the same site of primary tumor after CRT. Especially in case of carcinosarcoma, detection would be delayed because of rapid growing. But when the severe esophageal stenosis occurred after CRT, the examination of anal side become difficult. Therefore, it is necessary to observe by frequent CT or PET examination, or endoscopy from gastrostomy for early detection of recurrence or newly malignant neoplasm.