Colonoscopy for frank bloody stools associated with cancer chemotherapy.

Diarrhea is a common complication of cancer chemotherapy, while bloody stool is rare. Pseudomembranous colitis has been reported as causing bloody diarrhea after chemotherapy. In this report, we describe nine consecutive patients who presented frank bloody stools within one month after cancer chemotherapy. Patients with a history of pelvic irradiation or with a previously identified colorectal tumor were excluded. Among nine patients, bleeding from tumor undetected before chemotherapy was seen in three, pseudomembranous colitis in four, ischemic colitis in one and methicillin-resistant Staphylococcus aureus enterocolitis in one. Of the three tumors, one was an adenomatous polyp and the other two were metastatic tumors. Two of the four patients with pseudomembranous colitis had not received antibiotics before the onset of colitis. Causes of bloody stools after chemotherapy were various and colonoscopy played an important role in diagnosis and prompt therapy.