An assessment of the Mancuso study

Two papers (Mancuso, Stewart and Kneale, Health Physics; 33:369 (1977); and Kneale, Stewart and Mancuso, Reanalysis of the data relating to the Hanford study of the cancer risks of radiation workers, IAEA International Symposium on the Late Biological Effects of Ionizing Radiation, Vienna, March 1978) claim to demonstrate a significant excess of deaths among radiation workers at Hanford (USA) and attribute them to radiation-induced cancers. The work is important because it is essentially the only large scale study which has been reported of the effects of occupationally permitted levels of exposure to ionising radiation. However, both papers have been widely criticised on several substantial aspects. This report summarises some of the major points from these criticisms. The overall assessment is a rejection of the validity of the majority of the claims from the study. Other analyses of the same data indicate reasons for the incorrect conclusions drawn by Mancuso, Stewart and Kneale. From these analyses it is concluded that the only excess fatal malignancies at Hanford that may be associated with radiation are cancer of the pancreas and multiple myeloma. Even for these, further investigation is necessary since no attempt has been made to eliminate the possibility of the effects being due to other carcinogens. (author)