Reversible functional disorders of the intestinal tract caused by abdominal radiotherapy

: In 20 patients with malignancies receiving abdominal radiotherapy, tests for disturbed intestinal functions were performed at the beginning and at the end of the therapy and after 6 to 12 month following radiation. Four noninvasive tests were performed: 75Se-homotaurocholate (75SeHCAT) test for estimation of bile acid malabsorption; Schillings test for quantification of vitamin B12 absorption; H2-breath analysis before and after a test meal containing lactose as a parameter of lactose malabsorption; and 51Cr-EDTA test for estimation of intestinal permeability. Both bile acid and vitamin B12 absorption decreased significantly towards the end of abdominal radiotherapy in more than 50% of patients. Only one patient developed lactose malabsorption. After 6 to 12 month, these abnormalities had completely disappeared. In contrast, small intestinal permeability did not increase during radiotherapy but was significantly elevated 6 to 12 month following treatment as the only indication of chronic injury of small intestinal mucosa. During radiotherapy, a significant correlation existed between the severity of diarrhea and the degree of bile acid malabsorption.