For fatal cancers, these results strengthen those of the recent analysis of mortality based on death certificates on the same LSS cohort. Since atomic bomb radiation in Nagasaki consisted essentially of gamma rays, the present report provides a good opportunity to examine the shape of dose-response curve for gamma exposure. A linear model fits best or at least as well as a linear-quadratic model for many cancers other than leukemia, specifically, cancer of the breast, lung, stomach, and thyroid, where the fit of the quadratic model is not good. This is in contrast to leukemia where the quadratic model fits better than either the linear or the linear-quadratic model. Statistically, however, one cannot actually distinguish one model from another.
Further data are obviously necessary.