Skin cancers are generally divided into two broad categories—malignant melanomas and nonmelanotic skin cancers. According to the American Cancer Society, approximately 34,100 new cases of melanoma (ICD-9 172.0-172.9) were diagnosed in the United States in 1995, and some 7,200 persons died of this cancer (ACS, 1995). The incidence is similar in men and women, but men account for about 60 percent of deaths. Other skin cancers (basal-cell and squamous-cell carcinomas) led to about 800,000 new cases and 2,100 deaths. According to the committee's calculations, assuming that veterans have the same cancer rates as those of the general U.S. population, 486 cases of melanoma were expected among male Vietnam veterans and 1.1 among female veterans in the year 1995. For the year 2000, the expected numbers are 632 cases in male veterans and 1.3 in female veterans. No calculations were made for the very common and highly curable nonmelanotic skin cancers.
Most of the epidemiologic studies reviewed in VAO did not find an excess risk of skin cancer among TCDD-exposed workers or veterans. These included studies of chemical production workers in the United States and other countries (Suskind and Hertzberg, 1984; Lynge, 1985; Coggon et al., 1986; Bond et al., 1988; Zober et al., 1990; Fingerhut et al., 1991; Manz et al., 1991; Saracci et al., 1991), agricultural workers (Burmeister, 1981; Alavanja et al., 1988; Wigle et al., 1990; Hansen et al., 1992; Ronco et al., 1992), pesticide applicators (Blair, 1983; Swaen et al., 1992), Seveso residents (Pesatori et al., 1992), and Vietnam veterans (Lawrence et al., 1985; Boyle et al., 1987; Breslin et al., 1988; CDC, 1988; Anderson et al., 1986a,b). The lack of association was also seen in a study in which the cohort observed consisted of those with chloracne (Moses et al., 1984). One exception is melanoma mortality following the Seveso accident. Bertazzi et al. (1989a,b) found an elevated risk in males from Zones B and R, but this was based on two and one melanoma deaths, respectively. In addition, the Ranch Hand study (Wolfe et al., 1990) found a relative risk of 1.5 (CI 1.1-2.0) for nonmelanomic skin cancer. One study of agricultural workers in Sweden (Wiklund, 1983) found an elevated risk for skin cancer excluding melanoma (RR = 1.1, 99 percent CI 1.0-1.2), but these results may be confounded by sun exposure in these groups.
One more recent study reviewed by this committee did find an excess risk of skin cancer (Lynge, 1993). Melanoma was studied in employees of two phenoxy herbicide manufacturing facilities in Denmark. There were 1,651 men and 468 women who were judged to have had potential exposure to phenoxy herbicides.