[Epidemiological studies on malignant lymphoma in Nagasaki City, especially in relation to atomic bomb exposure]

One hundred and eighty-two (182) cases of malignant lymphoma registered at the Nagasaki Tumor Registry from 1973 to the end of 1977 were studied in relation to atomic bomb exposure. No significant difference in the incidence of malignant lymphoma was found between the exposed and nonexposed groups. One hundred and thirty-one (131) cases excluding Hodgkin's disease and mycosis fungoides were histologically reviewed and classified according to Lymphoma Study Group (L.S.G.) and Working Formulation (W.F.) Classifications. Using the L.S.G. Classification, the three histological types (diffuse large cell, diffuse pleomorphic, and diffuse medium sized cell) occupied 72.7% and 69.0% of the exposed and nonexposed groups respectively. No significant difference in histological type between the exposed and nonexposed groups could be found with an exception of a slightly higher incidence of the diffuse medium sized cell type in the exposed group than in the nonexposed group. An evaluation of these results was made in comparison with the results in Hiroshima.