Tsutomu Yamamoto

Cancer of the head and neck in atomic bomb survivors: Hiroshima and Nagasaki, 1957-1976

A search was conducted in Hiroshima and Nagasaki for all cases of cancer of the lip, nose and nasal cavity, accessory sinuses, larynx, and the oral cavity and pharynx with their subdivisions occurring during the period 1957–1976 among a large, fixed cohort of atomic bomb survivors. A total of 232 cases were identified, of which 154 (66.4%) were histologically confirmed (definite cases). Among definite cases, cancer of the epiglottis and larynx predominated (31.2%), followed by accessory sinus (24.7%) and tongue (18.8%). Of the 154 definite cases, 141 (91.6%) were squamous‐cell carcinomas. Only two sarcomas were identified, neither of which was attributable to radiation exposure. Analysis of both total and definite cases, by both total group and major anatomic site, failed to reveal definite evidence of a radiation relationship. Although a suggestive relationship to radiation dose was found for accessory sinus cancers (P = 0.06) among the definite cases, inconsistencies in the data do not permit the conclusion that the incidence of tumors in this group increased as a result of atomic bomb radiation exposure. The medical literature concerning post‐irradiation head and neck tumors is briefly reviewed.

Histologic review of breast cancer cases in survivors of atomic bombs in Hiroshima and Nagasaki, Japan

A panel of Japanese and American pathologists reviewed existing histologic material used to study breast cancer risk among the A‐bomb survivors in Hiroshima and Nagasaki, a population in which incidence studies have found a strong relationship between breast cancer risk and radiation dose. The primary charge to the panel was to define a body of confirmed cases in the Life Span Study sample of the Radiation Effects Research Foundation that would require little or no reveiw for inclusion in future studies of breast cancer incidence. Broad agreement on histologic type was reached for 298 of 300 confirmed cases. The distribution of histologic types was, overall, similar to that seen in other studies of breast cancer in Japanese women, and did not appear to depend on dose; thus radiation‐induced breast cancer appeared to be no different histologically from other breast cancer. Also, no evidence was found of variation in histologic type by city, age at exposure, age at diagnosis, or calendar time.