Nonmelanoma Skin Cancer
        Squamous cell carcinoma
        Basal cell carcinoma
Cutaneous Melanoma

Note: Separate PDQ summaries on Skin Cancer Screening ¹, Skin Cancer Treatment ², and Levels of Evidence for Cancer Screening and Prevention Studies ³ are also available.

There is inadequate evidence to determine whether the use of sunscreen reduces the incidence of squamous cell carcinoma of the skin.[1]

Description of the Evidence

• Study Design: One randomized controlled trial (RCT) with tumor incidence as the outcome and one RCT with actinic keratosis as the outcome. Other study designs give inconsistent results.
• Internal Validity: Poor.
• Consistency: Good.
• Magnitude of Effects on Health Outcomes: 39% point estimate reduction in tumor incidence (from one study).
• External Validity: Poor.

There is inadequate evidence to determine whether the use of sunscreen reduces the incidence of basal cell carcinoma of the skin.

Description of the Evidence

• Study Design: Evidence of association obtained from cohort studies.
• Internal Validity: Not applicable (N/A).
• Consistency: N/A.
• Magnitude of Effects on Health Outcomes: N/A.
• External Validity: N/A.

There is inadequate evidence to determine whether the avoidance of sunburns alters the incidence of cutaneous melanoma.

Description of the Evidence

• Study Design: Evidence of association only obtained from cohort or case-control studies.
• Internal Validity: Inadequate.
• Consistency: Poor.
• Magnitude of Effects on Health Outcomes: N/A.
• External Validity: N/A.

References

1. Green 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 354 (9180): 723-9, 1999.  [PUBMED Abstract]