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

Nonmelanoma Skin Cancer

Squamous cell carcinoma

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.

Basal cell carcinoma

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: N/A.
• CONSISTENCY: N/A.
• MAGNITUDE OF EFFECTS ON HEALTH OUTCOMES: N/A.
• EXTERNAL VALIDITY: N/A.

Cutaneous Melanoma

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.