Retinoids and carotenoids in cancer chemoprevention trials

: At the present time, cancer chemoprevention trials, especially non-randomised studies, constitute a large part of the scientific literature. Our purpose was to perform a critical analysis of the few randomised trials comparing a group treated with retinoids or carotenoids to an untreated control group or a placebo control group. Only one trial gave convincing results in favor of such chemoprevention, especially concerning the incidence of secondary cancer, at the cost of severe toxicity. Moreover, we have attempted to list the ongoing intervention trials which could provide details on the indications involved for such treatments.