Cancer incidence among workers occupationally exposed to dinitrotoluene in the copper mining industry

PURPOSE: Epidemiological and toxicological studies point to a potential carcinogenic effect of dinitrotoluene (DNT), particularly with respect to renal and urothelial cancer.

METHODS: The cohort comprised all men born between 1920 and 1974 (n = 16,441) who were gainfully employed between 1953 and 1990 in one of two underground copper mines in Mansfeld, Saxony-Anhalt, former German Democratic Republic, and who were followed up for cancer incidence, 1961-2005. Incident cancer cases were identified by record linkage with the Common Cancer Registry of the New Laender. Standardized incidence ratios (SIR) were calculated with the general population of Saxony-Anhalt as the reference.

RESULTS: Standardized incidence ratios for all cancers were not significantly elevated in the cohort (SIR = 1.04; 95 % confidence intervals (CI) 0.96-1.14). We found an increase in lung cancer (SIR = 1.29; 1.13-1.46), but not in kidney cancer (SIR = 1.01; 95 % CI 0.79-1.27) or bladder cancer (SIR = 1.04; 95 % CI 0.82-1.30). Standardized incidence ratios stratified by duration of employment with DNT exposure indicated moderately increased risks for kidney and bladder cancer in cohort members with longer exposure.

CONCLUSIONS: The SIR analysis of workers in the copper mining industry in comparison with the general population of Saxony-Anhalt overall did not indicate increased risks for renal or bladder cancer. However, results by years of exposure to DNT suggested weakly increased risks for outcomes of a priori interest, bladder and kidney cancer. A subsequent case-cohort analysis including expert assessment of DNT exposure and identification of additional cancer cases from a network of pathology institutes will provide further insight into a potential etiologic role of DNT in renal and urothelial cancer.