VIII. A. NEOPLASIA, NON-THYROID Malignancies Table 1 lists the malignancies in the exposed Rongelap and Utirik and unexposed Marshallese groups. (As indicated in Section II.C, the causes of many of the deaths over the years have been uncertain.) The most extensive data on the late effects of radiation on human beings appear in the reports on the Japanese victims of the atomic bombs at Hiroshima and Nagasaki. Beebe et al. (62) report that "although there have been 14,405 deaths from natural causes other than cancer, analysis of the whole material and its major components provided no support for the belief that diseases other than cancer are involved in the late mortality effect." The following cancers are listed by Beebe et al. (61,63) and other authors as being related to radiation exposure in the Japanese: leukemia (81~83,204), thyroid (84-87), lung (88), breast (89), gastrointestinal (stomach) (90,205), salivary gland (62), urinary tract (91), lymphoma (92), multiple myeloma (206), and possibly involvement of the large bowel, liver, and perhaps other organs (56,62,93-95). In Appendix V, from Shapiro (96), cancers in irradiated populations are tab- ulated. Despite differences in ethnicity and in types of exposure, the radiation-related cancers in the Marshallese would be expected to be generally similar to those reported in the Japanese. The only malignancies noted thus far that appeared to be related to radiation exposure (Table 1) are those of the thyroid in the Rongelap and Utirik populations and one case each of leuke- mia and cancer of the stomach in the Rongelap group. Thyroid neoplasia is discussed separately in Section IX.C.1l. The leukemia case has been discussed in detail in the 20-year report (1) and elsewhere (33). Acute myelogenous leukemia developed in a 19-year-old Marshallese male who had been exposed to 175 rads of gamma radiation at one year of age. At age 13 he had a subtotal thyroidectomy for removal of adenomatous nodules and was put on suppressive thyroxin treatment. He was treated for leukemia at the National Cancer Institute in Bethesda, MD, but responded poorly and died six weeks later. A preleukemic finding from retro- spective studies of his hemograms indicated that he had had a relative neu- tropenia compared with other exposed and unexposed peers over a number of years prior to the development of leukemia. The death from cancer of the stomach occurred in a 64-year-old Rongelap male who had been exposed to 175 rads of gamma radiation. The cancers of the female genital tract listed in Table 1 are not likely to be related to radia- tion exposure, on the basis of the Japanese data, particularly since they developed only a few years after exposure, and in older women. Table 2 shows the expected number of malignancies that might be due to radiation exposure, calculated by using the risk estimates (cases /10° people/ rad/yr) for the Japanese (97,99). Statistics on the spontaneous incidence of cancers of the various organs in the general Marshallese populations (with the possible exception of our data on the thyroid) are not sufficient to allow estimation of spontaneous incidence in the Marshallese study groups. However, statistics on other world populations (98) indicate that the number of sponta- neous cancers would be small. Table 2 shows that, except for the thyroid tumors, the small numbers of radiation-related cancers that might be expected - 47 -