A Case of Radically Resected Sigmoid Colon Cancer with Bladder Invasion after Chemotherapy and Weight Loss in an Extremely Obese Patient

A 30's extremely obese patient(body mass index: BMI 45 kg/m2)was referred to our hospital with a chief complaint of bloody urine and stool. Colonoscopy revealed a sigmoid colon tumor. Barium enema examination revealed stenosis of the sigmoid colon. CT scan showed a tumor in the sigmoid colon, with bladder invasion. The para-aortic lymph node was partially swollen. We considered surgery to be high risk because of the patient's severe obesity. Therefore, we decided to examine the possibility of radical surgery followed by chemotherapy(mFOLFOX6/cetuximab)with weight reduction. Following this, the tumor had shrunk remarkably, and the patient's BMI decreased from 45 kg/m2 to 39 kg/m2. The visceral fat area was reduced from 298 cm2 to 199 cm2 at the umbilical level. We then performed a sigmoid colectomy with partial resection of the bladder. Thus, chemotherapy combined with weight loss enabled us to perform radical surgery safely for a locally advanced sigmoid colon cancer in a patient with severe obesity.