Introduction We report the use of preoperative radiotherapy in a moribund patient with advanced carcinoma colon with complete intestinal obstruction who had undergone colostomy for a previous episode of intestinal obstruction. Methods Fifty-five-year-old man presented in Dec 2016 with acute intestinal obstruction with pain in abdomen and vomiting for 3 months. On exploratory laparotomy, a 12x15 cm hard mass in splenic flexure of colon was found involving root of mesentery, superior mesenteric vein and third part of duodenum and abutting tail of pancreas. Finding it unresectable, loop transverse colostomy was performed. He was started on Capecitabine. In Mar 2017, he presented to us in emaciated condition weighing 28 kilograms with acute intestinal obstruction with a large abdominal mass. He was started on nasogastric aspiration with total parenteral nutrition. Imaging revealed a 14x19 cm large abdominal mass involving pancreas, duodenum, spleen and transverse colon with dilated stomach. In view of poor general condition and advanced disease, the prognosis was discussed with the family and the idea of radiotherapy to relieve intestinal obstruction was discussed with family. After taking the consent, he was started on radiation therapy with 1.8 Gy per fraction after three-dimensional conformal radiation planning to spare maximum bowel. After 11 fractions, the patient started passing stools through the stoma. He was gradually started on enteral nutrition and was discharged to continue radiation therapy on outpatient basis. After 15 fractions, planning PET-CT scan was taken for adaptive therapy to make changes as per the reducing tumor size. He was also started on capecitabine as he was taking orally well. He completed 45 Gy in 25 fractions over 5 weeks. One month after completion of radiation therapy, he was found to be doing well and was planned for definitive surgery. Six weeks after the radiation therapy completion, extended left hemicolectomy with distal pancreatico-splenectomy and colostomy closure was performed. Histopathology showed residual viable poorly differentiated adenocarcinoma invading full thickness of colonic wall into pericolic soft tissues with a discontinuous microscopic nodular tumor deposit in pericolic soft tissue with all margins and nodes negative. Postoperatively, he developed biliary leak which healed with conservative management. Six weeks after the surgery, he recovered completely and was started on adjuvant Capecitabine. Five months after the surgery, he is doing well and is on oral Capecitabine. Conclusion To our knowledge, this is the first reported case of preoperative radiation therapy in advanced carcinoma colon and also in the setting of intestinal obstruction. Radiotherapy should be further tested in setting of malignant intestinal obstruction due to unresectable carcinoma colon and may spare patients with ileo/colostomy.

Citation Format: Amit Jain, Elumalai L, Punam Goswami. Preoperative radiation therapy in advanced carcinoma colon with post-colostomy intestinal obstruction: The first report [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 673.