Advances in the Use of Retinoids in Cancer Therapy and Prevention

Retinoids are natural and synthetic derivatives of vitamin A. The anticancer properties of retinoids have long been investigated in the preclinical, epidemiological and clinical settings. It is recognized that retinoids have potent, widespread and, in many ways, unprecedented anticancer activities. This chapter summarizes the current use of retinoids as cancer agents with emphasis on recent clinical advances and mechanistic insights for their optimal clinical utility. Promising results from a prospective randomized trial for the prevention of secondary hepatocellular carcinomas have been demonstrated with the acyclic retinoid polyprenoic acid. Retinoids have been tested for prevention of secondary cancers in head and neck and lung cancer. Systematic study of retinoid scheduling in animal models and phase 0 clinical trials may prove to be a fruitful approach to optimize retinoid use in the clinic. One approach to increase the efficacy of retinoids in advanced cancer is through combination therapy.