Background: More than 2 million cases of skin cancer are diagnosed annually in the United States, and melanoma incidence is increasing.

Purpose: To assist the U.S. Preventive Services Task Force in updating its 2003 recommendation on behavioral counseling to prevent skin cancer.

Data sources: Existing systematic reviews, database searches through February 2010, and outside experts.

Study selection: English-language, primary care-relevant counseling trials to promote sun-protective behaviors and studies examining the association between sun-protective behaviors and skin cancer outcomes or potential adverse effects were included.

Data extraction: Each study was appraised by using design-specific quality criteria. Important study details were abstracted into evidence tables.

Data synthesis: 11 fair- or good-quality, randomized, controlled trials examined the counseling interventions' effect on sun-protective behaviors. In young women, appearance-focused behavioral interventions decrease indoor tanning and ultraviolet exposure. In young adolescents, computer support can decrease midday sun exposure and increase sunscreen use. Thirty-five mainly fair-quality observational studies examined the relationship between ultraviolet exposure or sunscreen use and skin cancer. Increasing intermittent sun exposure in childhood is associated with an increased risk for squamous cell carcinoma, basal cell carcinoma, and melanoma. Evidence suggests that regular or early use of indoor tanning may increase melanoma risk. On the basis of 1 fair-quality trial, regular sunscreen use can prevent squamous cell carcinoma, but it is yet unclear if it can prevent basal cell carcinoma or melanoma.

Limitations: There are limited rigorous counseling trials. Observational studies are limited by the complexity of measuring ultraviolet exposure and sunscreen use, and inadequate adjustment for important confounders.

Conclusion: Randomized, controlled trials suggest that primary care-relevant counseling can increase sun-protective behaviors and decrease indoor tanning.