Heidenreich et al. have recently reported an analysis of the cancer incidence data for the atomic bomb survivors with mathematical models of carcinogenesis (1). The main result of the paper is, as expressed in the title, the suggestion of an evidence for a promoting radiation effect on carcinogenesis in several organs, i.e., of evidence for a radiation-induced growth of preneoplastic lesions. Such evidence was also found earlier for lung cancer incidence among the atomic bomb survivors (2). Heidenreich et al. (1) use the same assumed time Δt for the promoting effect (1 week) as was used in ref. (2).

Consistent with earlier work (3), Heidenreich et al. hypothesize that the promotional effect of radiation might be due to a replacement of normal cells that were killed by radiation. An alternative...