Three cases of human bladder cancer following high dose cyclamate ingestion.

Vesical implantation and oral feeding studies in animals raised sufficient suspicion of the carcinogenic propensity of cyclamates to result in their withdrawal from sale throughout the world. The structural similarity to known carcinogens, an effect on human chromosomes in tissue culture and a high carcinogenic potential when combined with non-injurious co-carcinogens gave further support to this ban. On the other hand, numerous epidemiological studies failed to support any statistical relationship between cyclamate ingestion and vesical carcinoma in man. Three patients are described in whom vesical carcinoma developed after a prolonged period of ingestion of an unusually high amount of cyclamate sweetener. Moreover, the severity of the disease appeared to be proportional to the dose ingested. Although this is not a conclusive indictment of the role of cyclamates we believe that patients with bladder cancer should be questioned about intake of cyclamates either directly or in diet soft drinks.