A pathology review of 553 lymphoid neoplasm cases among atomic bomb survivors provides WHO classification subtype distribution.
Significant radiation dose response observed for precursor lymphoid neoplasms but not for mature lymphoid neoplasms or HL.
Epidemiological data have provided limited and inconsistent evidence on the relationship between radiation exposure and lymphoid neoplasms. We classified 553 lymphoid neoplasm cases diagnosed between 1950 and 1994 in the Life Span Study cohort of atomic bomb survivors into World Health Organization subtypes. Mature B-cell neoplasms represented 58%, mature T-cell and natural killer (NK)-cell neoplasms 20%, precursor cell neoplasms 5%, and Hodgkin lymphoma (HL) 3%, with the remaining 15% classified as non-Hodgkin lymphoid (NHL) neoplasms or lymphoid neoplasms not otherwise specified. We used Poisson regression methods to assess the relationship between radiation exposure and the more common subtypes. As in earlier reports, a significant dose response for NHL neoplasms as a group was seen for males but not females. However, subtype analyses showed that radiation dose was strongly associated with increased precursor cell neoplasms rates, with an estimated excess relative risk per Gy of 16 (95% Confidence interval: 7.0, >533) at age 50. The current data based primarily of tissue-based diagnoses suggest that the association between radiation dose and lymphoid neoplasms as a group is largely driven by the radiation effect on precursor cell neoplasms while presenting no evidence of a radiation dose response for major categories of mature cell neoplasms, either B- or T-/NK-cell, or more specific disease entities (diffuse large B-cell lymphoma, plasma cell myeloma, adult T-cell leukemia/lymphoma) or HL.