Experimental evidence against the bile salt theory of colon carcinogenesis

According to the bile salt theory of colon carcinogenesis, therapeutic agents which increase the delivery of bile salts to the large intestine may promote colon cancer. The possibility that aluminium hydroxide (Aludrox), a bile salt binding agent, might facilitate colon carcinogenesis in vivo was tested experimentally, using the dimethylhydrazine (DMH)-induced rat colon cancer model. 48 Wistar rats were randomly allocated to 1 of 3 groups, all fed the same standard diet. Two groups received a course of ten weekly DMH injections. One was allowed fresh drinking water ad libitum whilst the other received Aludrox in their drinking water. A third group received weekly saline injections plus Aludrox in their drinking water. After 1 year's observation, there were no significant differences between the groups of DMH-injected rats given drinking water with or without Aludrox in respect of survival, necropsy incidence of primary or metastatic colon cancer, or in the total number of colon tumours per group. The results provide reassurance that Aludrox does not promote colon cancer and tend to contradict the bile salt theory of colon carcinogenesis.