Assessment of bone marrow infiltration in malignant lymphoma: importance of bone marrow examination and positron emission tomography-computed tomography

Abstract

Bone marrow infiltration （BMI） is a crucial factor in determining the stage of malignant lymphoma （ML）. However, the Lugano classification method suggests that a bone marrow examination is not required for routine staging of Hodgkin’s lymphoma （HL） and diffuse large B cell lymphoma （DLBCL）. Instead, positron emission tomography （PET）-computed tomography （CT） is recommended for the staging of ML, as it is noninvasive and allows for whole-body evaluation. Despite this, the use of PET-CT alone for BMI detection remains controversial. We investigated 253 patients with lymphoma who underwent bone marrow examinations at our hospital. We evaluated the diagnostic accuracy of BMI using bone marrow biopsy, aspiration, clot section, flow cytometry, and gene rearrangement. A BMI-positive case was defined as the detection of BMI using at least one of the abovementioned methods. The results revealed that 85 of 253 （34％） patients were BMI-positive. Biopsy showed the highest sensitivity （87％）, whereas gene rearrangement had the lowest sensitivity （45％）. To compare the usefulness of PET-CT and bone marrow examination for detecting BMI, we analyzed 90 patients with newly diagnosed lymphoma. Of these, 15 were BMI-positive using both PET-CT and bone marrow examination, 7 were BMI-positive using PET-CT but BMI-negative using bone marrow examination, and 6 were BMI-negative using PET-CT but BMI-positive using bone marrow examination. No patients with HL or DLBCL who showed negative PET-CT outcomes were found to be positive using bone marrow examination. However, of 31 patients with indolent lymphoma, 6 were found to be BMI-negative using PET-CT but BMI-positive using bone marrow examination. Our findings revealed that bone marrow examination may not be required to evaluate BMI if PET-CT is performed in patients with DLBCL or HL. However, only PET-CT may be inadequate for assessing BMI in indolent lymphoma.