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Information from PDQ -- for Health Professionals
Prevention of skin cancer
208/04733
** SUMMARY OF EVIDENCE **
Note: Separate PDQ summaries on Screening for Skin Cancer and Skin Cancer
Treatment are also available.
Nonmelanoma skin cancer:
Evidence suggests that reduction of exposure to ultraviolet (UV) radiation will
reduce the incidence of nonmelanoma skin cancer. Sun exposure can be reduced
by changing patterns of outdoor activities to reduce time of exposure to
high-intensity UV radiation, and by using adequate amounts of sufficiently
protective sunscreens or wearing protective clothing when exposed to
sunlight.[1]
Levels of Evidence for preceding statement: 1b,3aii,5
Evidence obtained from at least one well-designed and conducted randomized
controlled trial with a generally accepted intermediate endpoint
Evidence obtained from well-designed and conducted cohort or case-control
analytic studies, preferably from more than one center or research group, with
a cancer incidence endpoint
Opinions of respected authorities based on clinical experience or reports of
expert committees
Cutaneous melanoma:
Evidence suggests that avoidance of sunburns, especially in childhood and
adolescence, may reduce the incidence of cutaneous melanoma. Sunburn can be
avoided by changing patterns of outdoor activities to reduce time of exposure
to high-intensity UV radiation, by wearing protective clothing when exposed to
sunlight, and by using adequate amounts of sufficiently protective sunscreen.
Sunscreen is not a substitute for avoidance of sun exposure.[1,2]
Levels of Evidence for preceding statement: 3aii,4aii,5
Evidence obtained from well-designed and conducted cohort or case-control
analytic studies, preferably from more than one center or research group, with
a cancer incidence endpoint
Ecologic (descriptive) studies with a cancer incidence endpoint
Opinions of respected authorities based on clinical experience or reports of
expert committees
References:
1. Vainio H, Miller AB, Bianchini F: An international evaluation of the
cancer-preventive potential of sunscreens. International Journal of
Cancer 88(5): 838-842.
2. Autier P, Dore JF, et al, for the European Organization for Research and
Treatment of Cancer Melanoma Cooperative Group: Sunscreen use, wearing
clothes, and number of nevi in 6- to 7-year-old European children.
Journal of the National Cancer Institute 90(24): 1873-1880, 1998.
** SIGNIFICANCE **
Skin cancer is the most commonly occurring cancer in the United States. It
accounts for about 2% of all cancer deaths in the United States.[1] In 2002,
about 53,600 individuals are expected to develop melanoma and almost 7,400 will
die of melanoma.[2] There are 3 main types of skin cancer: basal cell
carcinoma, squamous cell carcinoma (together referred to as nonmelanoma skin
cancer), and melanoma. Basal cell carcinoma and squamous cell carcinoma are
the most common forms of skin cancer. The incidence of melanoma and
nonmelanoma skin cancer appears to be increasing,[3,4] although melanoma
incidence rates may have stabilized in the 1990s.[5] 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, although
the type of exposure (high-intensity intermittent versus chronic) and pattern
of exposure (continuous versus intermittent) may differ among the 3 main types
of skin cancer.[3,4,6]
The visible evidence of susceptibility to skin cancer (skin type, precancerous
lesions) and of sun-induced skin damage (sunburn, 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.
References:
1. American Cancer Society: Cancer Facts and Figures-1999. Atlanta, Ga:
American Cancer Society, 1999.
2. American Cancer Society: Cancer Facts and Figures-2002. Atlanta, Ga:
American Cancer Society, 2002.
3. Koh HK: Cutaneous melanoma. New England Journal of Medicine 325(3):
171-182, 1991.
4. Preston DS, Stern RS: Nonmelanoma cancers of the skin. New England
Journal of Medicine 327(23): 1649-1662, 1992.
5. Hall HI, Miller DR, Rogers JD, et al.: Update on the incidence and
mortality from melanoma in the United States. Journal of the American
Academy of Dermatology 40(1):35-42, 1999.
6. English DR, Armstrong BK, Kricker A, et al.: Case-control study of sun
exposure and squamous cell carcinoma of the skin. International Journal
of Cancer 77(3): 347-353, 1998.
** EVIDENCE OF BENEFIT **
Most evidence about 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.[1]
It is not known, however, if reduction of exposure to UV radiation through 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.[3] In Australia, 588 persons 40 years and older who attended a free
skin cancer screening clinic and had 1 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. 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.
The relationship between UV radiation exposure and cutaneous melanoma is less
clear. Rather than cumulative sun exposure, it is intermittent acute sun
exposure that seems to be more damaging; such exposures in childhood or
adolescence may be particularly important.[4] 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.[5,6] Non-modifiable 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.[4]
Several groups have conducted studies to learn more about possible intervention
strategies for reduction of exposure to UV radiation. The best weapon seems to
be education about the risks associated with sun exposure and sunburn and
education about sun protection strategies.[7,8] 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 that
seemed to have had the greatest impact - a time when an individual may have
recognized his or her susceptibility to skin cancer.[7] 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.[8] 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.[9] 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.[10]
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.[11] 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.[12,13] A randomized clinical trial
of long-term treatment with beta carotene in individuals previously treated for
nonmelanoma skin cancer showed no benefit for the occurrence of new nonmelanoma
skin cancers.[14] For both of these 2 trials, it is not known if 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 1312
patients with a history of basal-cell or squamous-cell skin cancer and a mean
follow-up of 6.4 years showed that 200 ug selenium (in brewer's yeast tablet)
did not have a significant effect on the primary endpoint of the development of
basal-cell or squamous-cell carcinoma of the skin.[15]
References:
1. Preston DS, Stern RS: Nonmelanoma cancers of the skin. New England
Journal of Medicine 327(23): 1649-1662, 1992.
2. English DR, Armstrong BK, Kricker A, et al.: Case-control study of sun
exposure and squamous cell carcinoma of the skin. International Journal
of Cancer 77(3): 347-353, 1998.
3. Thompson SC, Jolley D, Marks R: Reduction of solar keratoses by regular
sunscreen use. New England Journal of Medicine 329(16): 1147-1151,
1993.
4. Koh HK: Cutaneous melanoma. New England Journal of Medicine 325(3):
171-182, 1991.
5. Autier P, Dore JF, Schifflers E, et al.: Melanoma and use of sunscreens:
an EORTC case-control study in Germany, Belgium and France.
International Journal of Cancer 61(6): 749-755, 1995.
6. Wolf P, Donawho CK, Kripke ML: Effect of sunscreens on UV
radiation-induced enhancement of melanoma growth in mice. Journal of
the National Cancer Institute 86(2): 99-105, 1994.
7. Robinson JK: Compensation strategies in sun protection behaviors by a
population with nonmelanoma skin cancer. Preventive Medicine 21(6):
754-765, 1992.
8. Berwick M, Fine JA, Bolognia JL: Sun exposure and sunscreen use following
a community skin cancer screening. Preventive Medicine 21(3): 302-310,
1992.
9. Gruber SB, Roush GC, Barnhill RL: Sensitivity and specificity of
self-examination for cutaneous malignant melanoma risk factors.
American Journal of Preventive Medicine 9(1): 50-54, 1993.
10. Weinstock MA: Assessment of sun sensitivity by questionnaire: validity of
items and formulation of a prediction rule. Journal of Clinical
Epidemiology 45(5): 547-552, 1992.
11. Kraemer KH, DiGiovanna JJ, Moshell AN, et al.: Prevention of skin cancer
in xeroderma pigmentosum with the use of oral isotretinoin. New England
Journal of Medicine 318(25): 1633-1637, 1988.
12. The Isotretinoin-Basal Cell Carcinomas Study Group, Tangrea JA, Edwards
BK, et al.: Long-term therapy with low-dose isotretinoin for prevention
of basal cell carcinoma: a multicenter clinical trial. Journal of the
National Cancer Institute 84(5): 328-332, 1992.
13. The Isotretinoin-Basal Cell Carcinoma Study Group, Tangrea JA, Adrianza
E, et al.: Clinical and laboratory adverse effects associated with
long-term, low-dose isotretinoin: incidence and risk factors. Cancer
Epidemiology, Biomarkers and Prevention 2(4): 375-380, 1993.
14. The Skin Cancer Prevention Study Group, Greenberg ER, Baron JA, et al.: A
clinical trial of beta carotene to prevent basal-cell and squamous-cell
cancers of the skin. New England Journal of Medicine 323(12): 789-795,
1990.
15. Clark LC, Combs GF Jr, Turnbull BW, et al.: Effects of selenium
supplementation for cancer prevention in patients with carcinoma of the
skin: a randomized controlled trial. JAMA: Journal of the American
Medical Association 276(24): 1957-1963, 1996.
Date Last Modified: 05/2002
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