Cancer incidence and risk in Alaskan natives exposed to radioactive fallout

Summary

ABSTRACT. Cancer incidence in northern Alaskan villages exposed to radioactive fallout from nuclear weapons testing in the late 1950^s and early 1960^s was assessed using data from the Alaskan Native Tumor Registry. Previous studies have shown that cancer incidence in Alaskan natives differs from that in residents of the rest of the United States: rates of cancer of the nasopharynx and liver are higher in Alaskan native men and rates of cancer of the nasopharynx, gallbladder, cervix, and kidney are higher in Alaskan native women. Leukemia, breast cancer and bone sarcoma are the cancers most likely to result from fallout exposure in the Arctic, but the incidence of these cancers in the North Slope villages appeared to be lower than in either the entire Inuit population or the US population.

The fallout radionuclides of potential health concern are cesium–137 and strontium– 90, because of their abundance, long half-life, and chemical characteristics that facilitate transport through and concentration in the food chain and accumulaton in sensitive tissues of the body. Radionuclide body burdens were determined in North Slope Inuit 25 years ago, because of their possible exposure to radioactive fallout via the lichen-caribou-man pathway. Cancer risk estimates have been calculated using highest average dose measurements from residents of Anaktuvuk Pass, under the assumption that peak exposure levels of the mid 1960s remained steady over the following 20 years. Worst-case estimates of expected cancer excess were calculated for leukemia, breast cancer and bone sarcoma.