Ultraviolet effects on the incidence of skin cancer among whites in the United States (free format) Data Items 1 Gender 0 Female 1 Male 2 AgeFrom Lower Limit of age category 3 AgeTo Upper Limit of age category 4 City 1 Dallas-Forth Worth 2 Iowa 3 Minneapolis-St. Paul 4 San Francisco-Oakland 5 UVcount annual UV count (no units given) 6 R_nonM annual rate per 100,000 of non-melanoma skin cancer 7 N_nonM number of cases on which rate is based 8 R_M annual rate per 100,000 of skin melanoma 9 N_M number of cases on which rate is based ------------- Data extracted from Tables 1 and 2 in article "Mathematical Models of age and ultraviolet effects on the incidence of skin cancer among whites in the United States" by TR Fears, J Scotto and MA Schneidernan in Amer J of Epidemiology 105:420-427, 1977. Excerpts from article .... (INTRODUCTION) The skin, in protecting the body, is exposed to many environmental insults, some of which lead to cancer. It is not surprising, then, that skin neoplasms are common; but it is surprising that a single extrinsic factor, sunlight Ñ and in particular the ultraviolet (UV) component of sun light - is of overwhelming importance in the etiology of the disease. The associations which provide evidence in support of the role of ultraviolet have been swnmarized as follows (1): 1) skin cancers occur most frequently on exposed parts of the body; 2) those who have skin cancer also sunburn easily; 3) occurrence of skin cancer is higher among those who are outdoors much of the time; 4) the closer to the equator, the higher the incidence; ant 5) skin cancer can be produced in ani mals by exposure to ultraviolet radiation. There are three major types of skin cancer (2). Basal cell carcinomas are the most common among whites (3). They are slow growing, invade locally and rarely metastasize. While this type of lesion appears most frequently on the head, neck and upper extremities, exceptions are not uncommon (4). These tumors have not been produced in animals with ultraviolet radiation alone. Squamous cell carcinomas are the second most common skin cancer among whites. These lesions can be fast growing and do metastasize when left untreated. They occur predominantly on exposed areas of the body, even to a greater extent than basal cell carcinomas, and they have been produced on experimental animals by means of ultraviolet radiation alone (5). The least common of the three types of skin cancer is malignant melanoma, the form which is most frequently fatal. While melanomas occur often on exposed sites, they are also common on unexposed sites, particularly the trunk, among men. There is a clear, long-recognized asociation of melanoma incidence and latitude, which is strongest for the exposed sites. Malignant melanomas have not been produced in experimental mice with ultraviolet radiation alone, but they have been induced in association with chemicals (6). The evidence for the role of sunlight in the formation of skin cancer is generally considered stronger for squamous cell than for hsal cell carcinoma and stronger for nonmelanoma than for melanoma skin cancer (1). That sunlight leads to skin cancer has been recognized for nearly a century and is now generally accepted. As part of a continuing examination of this most common malignancy, the relationship between short-wavelength ultraviolet radiation (i.e., UVB:280-320 nm), age and skin cancer incidence rates was studied using a simple mathematical model. MATERIALS AND METHODS While nonmelanoma skin cancer is common among whites, it is also quickly and easily treated, frequently without hospitalization. The usual sources of cancer data are therefore not appropriate and accurate skin cancer incidence data have been difficult to obtain. In 1971-1972, a special nonmelanoma skin cancer survey was conducted as a part of the Third Na tional Cancer Survey. The results among whites are summarized by Scotto et al. (3). Detailed information on the incidence of malignant melanoma among whites was collected during 1989-1971 as a part of the Third National Cancer Survey (7). The wavelengths of ultraviolet radiation and their effectiveness for the production of skin cancer are believed to be similar to the action spectrum for human skin erythema (8) and can now be measured in the field by meters. During 1974, Robertson-Berger ultraviolet meters built by Temple University with the support of the Department of Transportation were placed at ten observatories of the National Oceanic and Atmospheric Administration and monitored by the National Weather Service. Four of the locations were selected because they were areas where the special skin cancer survey of the Third National Cancer Survey was conducted. Results are summarized by Scotto et al. (9). Several mathematical models have been proposed for the age distribution of cancer. Cook et al. (10) examined data from cancer registries and showed that, for many cancers, a simple power function provided a good description of age-specific incidence rates for ages 35 to 75. Doll (11) states, "No better description of the data has yet been proposed.... " RESULTS The ten-year age-specific incidence rate~ as well as~ the number of cases classified for white males and for white females, ages 35 to 75, are given for nonmelanoma in table 1 and for melanoma in table 2. Table 1 also provides the annual ultraviolet counts for 1974 at each location. ... (DISCUSSION) ... An estimate of age-specific skin cancer risk can be obtained for locations where W data are not available. Consider the risk for forty-year-old Caucasians in Oklahoma City where the latitude is 35.5¡ North and the altitude is 1280 feet: (1) Find the estimated W count for this location using the regression equation of table 2.4 of Scotto et al. (8): UVcount = 3220000 - 9613.9 (latitude) + 104.3 (altitude). For Oklahoma City we obtain an estimated count of 1,590,000. ... TABLE 1 Annual age-specifc incidence rates per 100,000 with number of cases classified for nonmelanoma skin cancer among whites in four areas, and the annual UVcount for each area Dallas- Iowa Minn. San Francisco Ft Worth St. Paul Oakland Age ______________________________________________ Group Gender-> M F M F M F M F 35-44 Rate 297.8 196.1 ... No. 179 119 45-54 Rate 760.5 396.9 ... No. 409 221 55-64 ... 65-74 Rate ... 1156.0 438.0 No. ... 391 203 UV "count" 1,605,936 1,251,567 1,065,035 1,508,568 Table 2 Annual age-specific incidence rates per 100,000 with number of cases classified for skin melanoma amorg whites in four areas Dallas- Iowa Minn. San Francisco Ft Worth St. Paul Oakland Age ______________________________________________ Group M F M F M F M F 35-44 Rate 12.5 11.0 ... No. 45 40 ... ... 65-74 Rate ... 11.8 8.3 No. ... 24 23