CANCER INCIDENCE IN A POPULATION ACCIDENTALLY EXPOSED TO 2,3,7,8-TETRACHLORODIBENZO-PARA-DIOXIN

In 1976, an accident in a plant near Seveso, Italy, exposed the local population to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Persons resi ding in three zones of decreasing TCDD contamination (A, B, and R) and a reference population were followed up for cancer occurrence in 1977 -1986. The most exposed subgroup (A) was small, and only 14 cancer cas es were observed. In zone B, hepatobiliary cancer was elevated, especi ally for those living in the area for >5 years [relative risk (RR) = 2 .8; 95% confidence interval (CI) = 1.2-6.3]. Men exhibited an increase in hematologic neoplasms, most notably lymphoreticulosarcoma (RR = 5. 7; 95% CI = 1.7-19.0). Women experienced an increased incidence of mul tiple myeloma (RR = 5.3; 95% CI = 1.2-22.6) and myeloid leukemia (RR = 3.7; 95% CI = 0.9-15.7). In zone R, the incidence of soft tissue tumo rs and non-Hodgkin's lymphomas was elevated, particularly among person s living in the area for >5 years (RR = 3.5; 95% CI = 1.2-10.4 for sar comas, and RR = 2.0; 95% CI = 1.2-3.6 for non-Hodgkin's lymphomas). Br east cancer among females was below expectations in the most contamina ted zones, and a clear deficit for endometrial cancer was observed in zones B and R.