Skin Cancer Prevention (PDQ®): Prevention - Health Professional Information [NCI]
This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http://cancer.gov or call 1-800-4-CANCER
Skin Cancer Prevention
Purpose of This PDQ Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about skin cancer prevention. This summary is reviewed regularly and updated as necessary by the PDQ Screening and Prevention Editorial Board.
Information about the following is included in this summary:
- Skin cancer incidence and mortality statistics and information about skin cancer risk factors.
- Interventions for skin cancer prevention.
- Benefits and harms of interventions to prevent skin cancer.
This summary is intended as a resource to inform clinicians and other health professionals about the currently available information on skin cancer prevention. The PDQ Screening and Prevention Editorial Board uses a formal evidence ranking system in reporting the evidence of benefit and potential harms associated with specific interventions. It does not provide formal guidelines or recommendations for making health care decisions. Information in this summary should not be used as a basis for reimbursement determinations.
This summary is also available in a patient version, which is written in less technical language.
Summary of Evidence
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.
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: 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.
|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.|
Skin cancer is the most commonly occurring cancer in the United States and accounts for about 4% of all cancer deaths. In 2009, it is estimated that 68,720 individuals in the United States will develop melanoma and approximately 8,650 are expected to die of it.
There are three main types of skin cancer: basal cell carcinoma, squamous cell carcinoma (together with basal cell carcinoma referred to as nonmelanoma skin cancer), and melanoma. Basal cell carcinoma and squamous cell carcinoma are the most common forms of skin cancer but have substantially better prognoses than the less common but generally more aggressive melanoma.
The incidence of melanoma and nonmelanoma skin cancer appears to be increasing,[3,4] though melanoma incidence rates may have stabilized in the 1990s. Epidemiologic evidence suggests that exposure to ultraviolet (UV) radiation and the sensitivity of an individual's skin to UV radiation are risk factors for skin cancer, though the type of exposure (high-intensity and short-duration vs. chronic exposure) and pattern of exposure (continuous vs. intermittent) may differ among the three main types of skin cancer.[3,4,6]
The visible evidence of susceptibility to skin cancer (skin type and precancerous lesions) and of sun-induced skin damage (sunburn and solar keratoses) and the ability of an individual to modify sun exposure provide the basis for implementation of programs for the primary prevention of skin cancer.
Evidence of Benefit
Most evidence about ultraviolet (UV) radiation exposure and the prevention of skin cancer comes from observational and analytic epidemiologic studies, not from experimental studies in humans. Such studies have consistently shown that increased cumulative sun exposure is a risk factor for nonmelanoma skin cancer.[1,2] Individuals whose skin tans poorly or burns easily after sun exposure are particularly susceptible.
It is not known, however, if reduction of exposure to UV radiation through the use of sunscreens and/or protective clothing or through limitation of exposure time can reduce the incidence of nonmelanoma skin cancer in humans. One study has shown that regular sunscreen use can reduce the incidence of solar keratoses (precursors of squamous cell carcinoma) and increase remissions of existing lesions. In Australia, 588 persons aged 40 years and older who attended a free skin cancer screening clinic and had one to 30 solar keratoses were enrolled in a randomized controlled trial assessing the effect that the regular use of sunscreen (sun protection factor 17) could have on solar keratoses; 431 persons completed the study. Persons in the sunscreen group developed significantly fewer new lesions and had significantly more remissions of existing lesions than persons in the base-cream group. Furthermore, the amount of sunscreen used was related to development of new lesions and remission of existing lesions in the sunscreen group; no such effect was observed in the base-cream group. A different Australian randomized study, however, showed that after 4.5 years of follow-up, there was no significant difference in incidence of squamous cell carcinomas after regular sunscreen use. Although a post hoc subgroup analysis showed a reduction in the frequency of carcinomas on the sites of daily sunscreen application, the validity of that finding is questionable because of the possible effects of multiple testing. An 8-year post-trial observational follow-up demonstrated statistically significant reductions in both the frequency and the overall incidence of squamous cell carcinomas in the regular sunscreen-use arm, but the reliability of these findings is uncertain given their occurrence outside of the controlled-trial environment.
The relationship between UV radiation exposure and cutaneous melanoma is less clear. Rather than cumulative sun exposure, it is intermittent acute sun exposure leading to sunburn that seems to be more damaging; such exposures in childhood or adolescence may be particularly important. Results from a collaborative European case-control study and one animal study, however, suggest that sunscreens that protect against sunburn may not protect against UV radiation-associated cutaneous melanoma.[8,9] Nonmodifiable host factors, such as propensity to burn, a large number of benign melanocytic nevi, and atypical nevi may also increase the risk of developing cutaneous melanoma. A meta-analysis of 18 studies that explored the association between melanoma risk and previous sunscreen use illustrates widely differing study qualities and suggests an absence of an association.
Several groups have conducted studies to learn more about possible intervention strategies for reduction of exposure to UV radiation. The best approach seems to be education about the risks associated with sun exposure and sunburn and education about sun protection strategies.[11,12] Although long-term reminders regarding recommendations for sun protection may have had some impact on reducing sun exposure in individuals who had been treated for nonmelanoma skin cancer, it was the educational intervention at the time of treatment—a time when an individual may have recognized his or her susceptibility to skin cancer—that seemed to have had the greatest impact. Even in this high-risk group, it was difficult for many individuals to maintain sun-protective behaviors. A community skin cancer screening study found that although regular use of sunscreens was not related to personal or family history of skin cancer, it was more common among persons who perceived themselves to be at moderate or high risk of developing melanoma. Sun-protective strategies may include avoiding sun exposure at times of the day when the exposure is more intense and wearing clothing that protects skin from sun exposure.
Self-examination for skin pigmentary characteristics associated with melanoma (e.g., freckling status) may be a useful way to identify individuals at increased risk of developing melanoma. Skin type (propensity to burn after sun exposure, tanning ability), alone or with other physical characteristics such as hair color, has been used as a measure of sun sensitivity in epidemiologic studies.
The efficacy of chemopreventive agents (isotretinoin, beta carotene) has been assessed in individuals at increased risk of developing nonmelanoma skin cancer. High-dose isotretinoin was found to prevent new skin cancers in individuals with xeroderma pigmentosum. A randomized clinical trial of long-term treatment with isotretinoin in individuals previously treated for basal cell carcinoma, however, showed that such treatment did not prevent the occurrence of new basal cell carcinomas but did produce side effects characteristic of isotretinoin treatment.[16,17] Randomized clinical trials of long-term treatment with beta carotene in individuals previously treated for nonmelanoma skin cancer showed no benefit in preventing the occurrence of new nonmelanoma skin cancers.[4,18] For all of these trials, it is not known whether treatment would benefit individuals at high-risk (sun-damaged skin) who have not yet developed skin cancer or if longer follow-up would show a long-term effect in the prevention of subsequent skin cancers.
A multicenter, double-blind, randomized, placebo-controlled trial of 1,312 patients with a history of basal cell or squamous cell skin cancer and a mean follow-up of 6.4 years showed that 200 µg selenium (in brewer's yeast tablets) did not have a significant effect on the primary endpoint of the development of basal cell carcinoma of the skin and may increase the risk of squamous cell carcinoma and total nonmelanoma skin cancer.[19,20]
Get More Information From NCI
For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 9:00 a.m. to 4:30 p.m. A trained Cancer Information Specialist is available to answer your questions.
The NCI's LiveHelp® online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 9:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.
WRITE TO US
For more information from the NCI, please write to this address:
|NCI Public Inquiries Office|
|6116 Executive Boulevard, MSC8322|
|Bethesda, MD 20892-8322|
SEARCH THE NCI WEB SITE
The NCI Web site provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. For a quick search, use the search box in the upper right corner of each Web page. The results for a wide range of search terms will include a list of "Best Bets," editorially chosen Web pages that are most closely related to the search term entered.
There are also many other places to get materials and information about cancer treatment and services. Hospitals in your area may have information about local and regional agencies that have information on finances, getting to and from treatment, receiving care at home, and dealing with problems related to cancer treatment.
The NCI has booklets and other materials for patients, health professionals, and the public. These publications discuss types of cancer, methods of cancer treatment, coping with cancer, and clinical trials. Some publications provide information on tests for cancer, cancer causes and prevention, cancer statistics, and NCI research activities. NCI materials on these and other topics may be ordered online or printed directly from the NCI Publications Locator. These materials can also be ordered by telephone from the Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237).
Changes To This Summary (06 / 30 / 2009)
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Updated incidence and mortality estimates for 2009 (cited American Cancer Society as reference 2).
Questions or Comments About This Summary
If you have questions or comments about this summary, please send them to Cancer.gov through the Web site's Contact Form. We can respond only to email messages written in English.
- PDQ® - NCI's Comprehensive Cancer Database.
Full description of the NCI PDQ database.
ADDITIONAL PDQ SUMMARIES
- PDQ® Cancer Information Summaries: Adult Treatment
Treatment options for adult cancers.
- PDQ® Cancer Information Summaries: Pediatric Treatment
Treatment options for childhood cancers.
- PDQ® Cancer Information Summaries: Supportive and Palliative Care
Side effects of cancer treatment, management of cancer-related complications and pain, and psychosocial concerns.
- PDQ® Cancer Information Summaries: Screening/Detection (Testing for Cancer)
Tests or procedures that detect specific types of cancer.
- PDQ® Cancer Information Summaries: Prevention
Risk factors and methods to increase chances of preventing specific types of cancer.
- PDQ® Cancer Information Summaries: Genetics
Genetics of specific cancers and inherited cancer syndromes, and ethical, legal, and social concerns.
- PDQ® Cancer Information Summaries: Complementary and Alternative Medicine
Information about complementary and alternative forms of treatment for patients with cancer.
This information is intended mainly for use by doctors and other health care professionals. If you have questions about this topic, you can ask your doctor, or call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
Date Last Modified: 2009-06-30