Clinico-hematologic Findings of Leukemic Bone Marrow Involvement in Korean Patients with Non-Hodgkin Lymphoma

ABSTRACT

BACKGROUND: The purpose of the present study was to investigate the clinico-hematological findings of bone marrow (BM) involvement and leukemic phase in Korean patients with non-Hodgkin lymphoma (NHL). METHODS: We included 791 patients with NHL that were classified with the WHO (2008) criteria. Laboratory data, bone marrow histomorphologic features and medical records were reviewed. Leukemic phase was defined as when the proportion of neoplastic lymphoid cells comprised more than 10% of leukocytes in the peripheral blood or more than 25% of nucleated cells in the BM. RESULTS: We found that 21.7% (172/791) of the patients had BM involvement, and 6.2% (49/791) developed leukemic phase of the disease. NHL subtypes showing high frequencies of leukemic phase development were mantle cell lymphoma (40%), angioimmunoblastic T cell lymphoma (40%), lymphoblastic lymphoma (36.4%), and Burkitt lymphoma (26.1%). Compared to B-cell type, T-cell type of NHL showed significantly higher frequencies of BM involvement (18.6% vs 30.9%; P=0.0004) and leukemic phase development (4.8% vs 10.3%, P=0.008). Complete remission rate was significantly lower in leukemic (55.6%) than in non-leukemic (85.9%) group of patients (P=0.0002), whereas relapse rate was not different between the two groups. Death rate was higher in leukemic (46.9%) than in non-leukemic (30.1%) group of patients, and the 5-yr overall survival probability was significantly lower in leukemic group (P=0.02). CONCLUSIONS: The incidence of leukemic phase development in NHL was lower in Korean patients than that reported for Western populations and higher in T-cell lymphoma. We confirmed that the presence of leukemic phase in NHL patients is associated with a poor prognosis.