Robin Marks, Professor of Dermatology, University of Melbourne, comments:
Dr Joseph has raised an interesting point about the possible carcinogenic effect of the use of topical tretinoin or alpha-hydroxy acid creams because of the tendency to either irritate the skin, or else sensitise it to sunlight.
One of the problems with the use of tretinoin is that it sensitises the skin to sunlight and people will burn easily without adequate photo protection. A history of sunburn in the past is one of the risk factors for skin cancer, both for melanoma and for non-melanoma skin cancers. Thus, it seems logical to query whether or not the use of tretinoin might enhance the risk of skin cancer.
The answer is that there is no evidence that it does so. On the contrary, tretinoin has been reported to be useful in reducing carcinogenic risk. It has been used topically to treat solar keratoses and thus prevent their progression. It has also been used systemically in chronic immuno suppressed patients to delay the development of squamous cell carcinoma in particular, but also basal cell carcinoma. There are no data available on either carcinogenic risk, or reduction of carcinogenesis, for alpha-hydroxy acid creams.
In summary, photo protection is advised with the use of tretinoin or alpha-hydroxy acid creams. However, it is largely related to preventing the short-term effects of acute photosensitivity, rather than because of any established long-term risk of carcinogenesis.
