The weight of the evidence from metabolic studies, short-term tests, animal bioassays, and epidemiological studies indicates that
cyclamate (CHS) is not carcinogenic by itself; however, there is evidence from in vitro and in vivo studies in animals that implies it may have
cancer-promoting or cocarcinogenic activity. Epidemiological studies indicate that the use of nonnutritive
sweeteners (CHS and
saccharin) has not resulted in a measurable overall increase in the risk of
bladder cancer in individuals who have ever used these products. No epidemiological information exists on the possible associations of these
sweeteners and
cancers other than those of the urinary tract. It is recommended that (1) no further studies on the metabolism of CHS to evaluate its carcinogenicity are required since no potentially hazardous metabolites have been appreciably detected in humans; (2) no further animal bioassays to test for the carcinogenicity of CHS by itself are necessary; (3) the studies in rodents that suggest a promotional or cocarcinogenic effect of CHS should be repeated because they cannot be ruled out; (4) because the significance to human health of a positive outcome of such studies is uncertain, additional research aimed at understanding the predictive value for human health of such results and more generic studies to develop well-validated systems that can be relied on in the assessment of
cancer-promoting agents are recommended; (5) in populations where CHS continues to be used, epidemiological monitoring should be continued to determine whether there is an increased risk of
cancer in humans who are heavy or long-term users or for those observed long after first exposure. In such monitoring, other
cancer sites--in addition to the bladder--should be considered.