Carta Revisado por pares

Betacarotene and sunscreen use

1999; Elsevier BV; Volume: 354; Issue: 9196 Linguagem: Inglês

10.1016/s0140-6736(05)77066-5

ISSN

1474-547X

Autores

Jeffrey A. Linder, Jeffrey A. Tice,

Tópico(s)

Photodynamic Therapy Research Studies

Resumo

Adèle Green and colleagues1Green A Williams G Neale R et al.Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial.Lancet. 1999; 354 (published erratum appears in Lancet 1999; 354: 1038).: 723-729Summary Full Text Full Text PDF PubMed Scopus (832) Google Scholar describe the results of the Nambour Skin Cancer Prevention Trial, a randomised trial that evaluated betacarotene and sunscreen in the prevention of basal-cell carcinoma and SCC of the skin. Although a trial on this topic is welcome and long overdue, the investigators and the commentator David Hill2Hill D Efficacy of sunscreens in protection against skin cancer.Lancet. 1999; 354: 699-700Summary Full Text Full Text PDF PubMed Scopus (16) Google Scholar will have to forgive our wry smile when we examine the cost-effectiveness of this intervention in places other than the Sunshine Coast of Australia. If one uses the total tumour incidence as reported in their table 2 as the primary outcome, the absolute risk reduction of SCC is 0·72% per year. This yields a 1-year number needed to treat of 139. The cost of 139 people using four bottles per year of the sunscreen used in the trial (AU$8·79 per bottle) is AU$4887 to prevent one individual from getting one SCC. By contrast, charges at the University of California, San Francisco to treat a large (>4 cm) SCC on the forearm, including initial dermatology visit, punch biopsy, excisional biopsy, dermatopathological fees, and a follow-up visit is AU$3050. Any benefit of daily sunscreen would be greatly reduced in a population with a lower incidence of SCC. A recent US study found the incidence of SCC to be 64·8/100 000 persons per year,3Karagas MR Greenberg RE Spencer SK Stukel TA Mott LA Increase in incidence rates of basal cell and squamous cell skin cancer in New Hampshire, USA.Int J Cancer. 1999; 81: 555-559Crossref PubMed Scopus (268) Google Scholar about 20-fold less than in Nambour, Australia. The relative risk reduction of 0·61 found by Green and colleagues yields a number needed to treat of almost 4000 people at a cost of AU$140 000 of sunscreen to prevent a single SCC in this US population. Of course there are other reasons for sun avoidance and sunscreen use: painful sunburn, photodamage, and other skin cancers. We believe that the promotion of sunscreen use during times of high exposure is crucial, but the findings of Green and colleagues do not support the use of daily sunscreen in adults as a cost-effective, public-health measure.

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