Background The use of sunscreens on the skin can prevent sunburn but whether long-term use can prevent skin cancer is not known.
Also, there is evidence that oral betacarotene supplementation lowers skin-cancer rates in animals, but there is limited evidence of its effect in human beings.
Methods In a community-based randomised trial with a 2 by 2 factorial design, individuals were assigned to four treatment groups :
daily application of a sun protection factor 15-plus sunscreen to the head, neck, arms, and hands, and betacarotene supplementation (30 mg per day) ;
sunscreen plus placebo tablets ;
betacarotene only ;
or placebo only.
Participants were 1621 residents of Nambour in southeast Queensland, Australia.
The endpoints after 4.5 years of follow-up were the incidence of basal-cell and squamous-cell carcinomas both in terms of people treated for newly diagnosed disease and in terms of the numbers of tumours that occurred.
Analysis of the effect of sunscreen was based only on skin cancers that developed on sites of daily application.
All analyses were by intention to treat.
Findings 1383 participants underwent full skin examination by a dermatologist in the follow-up period. 250 of them developed 758 new skin cancers during the follow-up period.
There were no significant differences in the incidence of first new skin cancers between groups randomly assigned daily sunscreen and no daily sunscreen (basal-cell carcinoma 2588 vs 2509 per 100 000 ; rate ratio 1. (...)
Mots-clés Pascal : Carcinome basocellulaire, Carcinome épidermoïde, Bétacarotène, Supplémentation, Voie orale, Crème, Soleil, Protection, Etude en condition contrôlée, Prévention, Homme, Randomisation, Peau pathologie, Tumeur maligne
Mots-clés Pascal anglais : Basal cell carcinoma, Squamous cell carcinoma, Betacarotene, Supplementation, Oral administration, Cream, Sun, Protection, Controlled environment study, Prevention, Human, Randomization, Skin disease, Malignant tumor
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0449363
Code Inist : 002B08A. Création : 22/03/2000.