Evidence Table. Selected Randomized Trials of Skin Cancer Prevention and Counseling

Sunscreen Trials

SubjectsTopicDesignQualityResults
Children in Vancouver, B.C.71 Efficacy of sunscreen vs. no sunscreen in preventing nevi. 458 randomized; treated group (n=222) given sunscreen and instructions to use it; controls (n=236) were not given any. 309 children completed 3 years of followup. Fair-poor: baseline differences in groups; not blinded; did not use intention-to-treat analysis At baseline, grade 1 students had 41 nevi (median) and grade 4 students had 68 nevi. By the end of the study, children in the treated group developed a median of 24 new nevi vs. 28 new nevi in the control group (P=.048).
Residents of Nambour, Australia70 Efficacy of sunscreen vs. placebo in preventing NMSC.* 1,621 randomized; 1,383 completed 4 1/2 years of followup. Outcome measure: new skin cancers. Analysis: intention-to-treat. Good No difference in the incidence of first cancers. Sunscreen reduced the total incidence of squamous cell cancers but not basal cell cancers. The number needed to treat (NNT) to prevent one squamous cell cancer was 140.
Residents of Maryborough, Australia over 40 with solar keratoses68,69 Effect of sunscreen plus moisturizer vs. moisturizer alone on solar keratoses. 588 began study; 431 completed it; 417 (71%) had complete data. Outcome measure: ratio of numbers of solar keratoses at end of study and beginning of study. Good 1.6 new lesions per subject in the sunscreen group, vs. 2.3 in the moisturizer group (adjusted relative risk [ARR], 0.72; CI, .15-1.28). Remission of base-line lesions, 2.2 vs. 1.4 per subject (ARR, .814).
Residents of Maryborough, Australia over 40 with solar keratoses83 Effect of sunscreen plus moisturizer vs. moisturizer alone on vitamin D levels
 Substudy of Thompson, 1993 study (68). 153 began the substudy; 113 completed one summer of followup. Outcome measures: 25-hydroxyvitamin D3 levels and 1,25-dihydroxyvitamin D3.
 Good
 Sunscreen: 25-hydroxyvitamin D3 levels rose by a similar amount in both groups. 1,25-dihydroxyvitamin D3 increased significantly in the placebo group only (placebo, +10.8 pmol/L; sunscreen, +1.3 pmol/L; P=.0009), but no individual developed a level below the lower limit of the reference range.
French and Swiss paid volunteers 18-24 years of age who had a history of sunburn and who were regular sunscreen users (2 trials)78,79 Effect of sunscreen with high sun protection factor (SPF 30) versus low (SPF 10) on sun avoidance behavior. 86 of 87 completed one summer of followup. Outcome measures: cumulative sun exposure, sunburn episodes. Fair The SPF 30 group spent 72.6 hours in the sun, versus 58.2 hours for the SPF 10 group (P =.011). There was no difference in sunburn experience between the two groups, but the incidences of sunburn (45%) and skin-reddening episodes (81%) were high.

*NMSC - non-melanoma skin cancer. ARR - Adjusted relative risk.

Community-based Intervention Including a Primary Care Counseling Component

SubjectsTopicDesignQualityResults
Children in 10 New Hampshire low-income towns with populations between 5,000 and 15,00044,50 Community-based promotion (5 towns) of SunSafe message vs. controls (5 towns) in day care, schools, beach areas, and physicians' offices.Children 2 to 9 years of age who visited beaches between 10 AM and 3 PM were measured before and after the intervention (summer, 1995 vs. summer, 1996). Outcome measures: use of protective clothing, sunscreen, shade, hats with brim. Good Sunscreen use, but not clothing or shade use, increased significantly in intervention towns. In intervention towns, the proportion of children with some sun protection increased from 78% to 87%, while in controls the proportion fell from 85% to 80% (P=.029). In the first summer, the proportion using full protection increased from 53% to 74% in intervention towns vs. 66% to 72% in controls (P=.18). The difference persisted after 2 years of followup.
Children in 10 New Hampshire low-income towns with populations between 5,000 and 15,00086 Practice meeting and materials to help practices in establishing an office system to promote sun protection advice to children. 86 clinicians, including 15 of 21 intervention-town practices. Good Before the intervention, 25% of parents reported that they had received sun protection information from a clinician. Afterwards, 34% of parents in intervention towns vs. 27% in control towns reported this.

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