Positive Health Online

Abstract

Green and colleagues, Epidemiology and Population Health Unit, Queensland Institute of Medical Research, Brisbane, University of Queensland, Australia. AdeleG@qimr.edu.au write that the use of sunscreens on the skin may prevent sunburn ; however it is not known whether long-term use can prevent skin cancer . There is evidence that oral betacarotene supplementation lowers skin-cancer rates in animals; however, evidence of its effects in human beings is limited.

Background

Methodology

The authors conducted a randomised controlled clinical trial. Participants, 1621 residents of Nambour in southeast Queenland Australia, were assigned to one of four treatment group: 1) daily application of a sun protection factor 15-plus sunscreen to the head, neck, arms and hands and betacarotene supplementation of 30 mg daily; 2) sunscreen plus placebo tablets; 3) betacarotene only; or 4) placebo only. Endpoints after 4.5 years of follow-up were incidence of basal-cell and squamous-cell cancers, for people treated for newly diagnosed disease and number of tumours which occurred. The analysis of the sunscreens effect was based only on skin cancers which developed on the sites of daily application. All analyses were by intention to treat.

Results

1838 participants underwent full skin examination by a dermatologist in the follow-up period. 250 of these individuals developed 758 new skin cancer during follow-up. There were no significant differences in incidence of first new skin cancers between groups randomly assigned daily sunscreen and no sunscreen . Also, there was no significant difference between the betacarotene and placebo groups in the incidence of either cancer . There was no effect upon the incidence of basal-cell carcinoma by sunscreen use or by betacarotene regarding number of tumours ; however the incidence of squamous-cell carcinoma was significantly lower in the sunscreen group than in the no-daily sunscreen group .

Conclusion

References

Green A et al. Daily sunscreen application and betaacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial. Lancet 354(9180) 723-9 28 Aug 1999.

Comment

With the incidence of skin cancer rising due, supposedly to greater unprotected sun exposure, these results reporting significant reductions in squamous-cell cancer following the use of sunscreen are encouraging.