Description:
<jats:p>Occurrence of second hematopoietic malignancies (SHM) among 49,163 patients with cancer, who had been admitted to the National Cancer Center Hospital from 1962 to 1987, was investigated. Forty‐two cases of malignant lymphomas (38 non‐Hodgkin lymphomas, 3 Hodgkin's diseases and 1 multiple myeloma) and 17 cases of leukemias (11 acute leukemias, 4 chronic leukemias and 2 myelodysplastic syndromes) developed as SHM. Second malignant lymphomas were 1.37 times more frequent than expected (<jats:italic>P</jats:italic><0.05), whereas no excess incidence was seen in second leukemias. The incidence of malignant lymphomas was 2.2 times higher than expected in patients with initial stomach cancer (<jats:italic>P</jats:italic><0.01). Two‐thirds of second non‐Hodgkin lymphomas occurred in extranodal regions. Nodal lymphomas were more prevalent in cases treated with chemotherapy and/or radiotherapy. Second leukemias were all of myeloid origin except one case of acute lymphoblastic leukemia. Etiological heterogeneity of SHM is discussed in relation to treatment and other risk factors.</jats:p>