women, respectively. In Zone R, the least contaminated area, there were 39 and four bladder cancers diagnosed in men and women, respectively. None of these subgroups demonstrated a significant increase in relative risk. These results are very similar to the previous reports on bladder cancer incidence and mortality in the Seveso population (Bertazzi et al., 1989 a,b; Pesatori et al., 1992).

Summary

The additional evidence since publication of VAO does not warrant changing the conclusion on bladder cancer and herbicide exposure.

Conclusions

There is limited/suggestive evidence of no association between exposure to the herbicides (2,4-D, 2,4,5-T and its contaminant, TCDD; cacodylic acid; and picloram) and urinary bladder cancer. The evidence regarding association is drawn from occupational and other studies in which subjects were exposed to a variety of herbicides and herbicide components.

Testicular Cancer

Summary of VAO

A case-control study of 137 testicular cancer cases and 130 hospital controls (Tarone et al., 1991) found an odds ratio of 2.3 (CI 1.0-5.5) for service in Vietnam. Risk for testicular cancer was not significantly elevated by service branch. In general, the other veteran studies and most of the occupational and environmental studies have shown no association between exposure and outcome, but the sample size of some of these studies may have been too small to detect an elevated risk. Other studies of testicular cancer have generally been inconsistent. These include studies of chemical production workers in the United States and other countries (Bond et al., 1988; Saracci et al., 1991), agricultural workers (Wiklund, 1983; Ronco et al., 1992), residents of Seveso (Pesatori et al., 1992), and Vietnam veterans (Anderson et al., 1986a,b; Boyle et al., 1987; Breslin et al., 1988; Watanabe et al., 1991).

Update of the Scientific Literature

A PCMR study was performed for farmers in 23 states, using occupational information from death certificates (Blair et al., 1993). Based on 32 deaths from testicular cancer in white male farmers, the PCMR was 0.8 (CI 0.6-1.2). Based on six deaths from testicular cancer in nonwhite male farmers, the PCMR was 1.3 (CI 0.5-2.9).



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