The effects of lifetime feeding studies on patterns of senile lesions in mice and rats

Data from lifetime feeding studies in mice and rats comparing controls to three doses of Xylitol, to Sorbitol, and to sucrose are examined to illustrate the thesis that the occurrence of some tumors is often confounded with other lesions and even other tumors in lifetime feeding studies. It is suggested that it may be impossible to test whether a treatment is a "carcinogen" in the presence of such biological confounding.