CANCER INCIDENCE AND MORTALITY IN WOMEN OCCUPATIONALLY EXPOSED TO CHLOROPHENOXY HERBICIDES, CHLOROPHENOLS, AND DIOXINS

The association between exposure to chlorophenoxy herbicides contamina ted with dioxins and occurrence of cancer has been studied mainly in m ale populations. In animal experiments, gender differences have been r ecorded in the cancer response to administered 2,3,7,8-tetrachlorodibe nzo-p-dioxin (TCDD). Mortality and cancer incidence in an internationa l cohort of 701 women from an International Register of Workers occupa tionally exposed to chlorophenoxy herbicides, chlorophenols, and dioxi ns is examined. Cause-specific, national death rates and cancer incide nce rates were used as referents. Cancer risk was not increased overal l, with a standardized incidence ratio (SIR) of 96 and 95 percent conf idence interval (CI) of 64-137, based on 29 cases. Among workers expos ed to those chlorophenoxy herbicides contaminated with TCDD, excess ca ncer incidence (for all sites) was observed (SIR = 222, CI = 102-422, 9 cases); this was highest in the first 10 years after exposure. No ex cess was observed for breast cancer, the most common cancer in this co hort. Results on cancer mortality were consistent with those on incide nce.