Clinical epidemiology

Abstract

Although the exact incidence of chronic myeloid leukemia(CML) in Japan is obscure, the occurrence rate of CML is approximately 15% of all leukemia patients in Japan, and thus about 5/100,000 cases appeared per year. This incidence of CML seems to be lower that that of Caucasian, but the incidence of CML patients in Japan may increase gradually. Molecular investigation in CML disclosed the exact mechanism of t(9; 22) anomaly, thus providing appropriate classification for chronic myeloid leukemia. From the etiological aspect, it is well documented that exposure to atomic bomb at Nagasaki and Hiroshima actually induced CML, however, factors other than irradiation are still obscure. Recent spread of annual examination pick up some CML patients at the early phase and the disease severity might be thus different from those of previous CML patients. For example, currently diagnosed CML patients usually lack palpable splenomegaly and some of them had normal karyotypes in addition to Ph-cells in the bone marrow at the time of CML diagnosis. These findings indicate that epidemiological aspect in CML patients might be changing.