Retinoids in the chemoprevention of non-melanoma skin cancers: why, when and how.

The chemoprevention refers to the use of various types of chemical agents for preventing carcinogenic progression. Systemic retinoids are the most studied chemopreventive agents due to their capacity to regulate cell proliferation and their demonstrated efficacy in several clinical studies. The aim of the authors was to give precise indications regarding the use of the systemic retinoid in the chemoprevention of non-melanoma skin cancer (NMSC). The authors reviewed the literature found through a search to MEDLINE (from 2001 to December 2011). Both acitretin and isotretinoin are effective for the prevention of NMSC. Isotretinoin is preferred in xeroderma pigmentosum and nevoid basal cell carcinoma syndrome, whereas acitretin is more used in transplant recipients, psoriasis and severe sun damage. Despite numerous studies of the literature concerning retinoids in chemoprevention of NMSC, precise details of the type of retinoid to use, dosage and the duration of this preventive treatment and how to manage side effects in the case of long-lasting treatment are still not uniform and comparable. Moreover, neither guidelines nor approval by Food and Drug Administration exist to regulate the use of retinoids in chemoprevention.