Background Bone marrow involvement confers a poor prognosis in patients with diffuse, large, B-cell lymphoma (DLBCL). However, the prognostic significance of concordant and discordant bone marrow involvement in these cases differs. We analysed this further in patients treated with R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone) at a single institute.

Design and Methods The cytomorphology of bone marrow involvement was evaluated in 632 patients who were diagnosed with DLBCL in primary tissues and had received R-CHOP therapy. Bone marrow trephine biopsies and clot sections were analysed, along with the immunohistochemical analysis of CD20, CD79a and CD3.

Results Bone marrow involvement was identified in 80 of our DLBCL patient subjects (12.7%). Of these, 32 (40%) showed discordant bone marrow involvement, and 48 (60%) showed concordant involvement. Kaplan–Meier survival analysis showed that progression-free survival and overall survival was poorer in the concordant group (p<0.001). Multivariate analysis, adjusted for the International Prognostic Index score, showed that concordant involvement was an independent predictor of progression-free survival (p<0.001) and overall survival (p=0.011). Discordant involvement was not a negative prognostic factor independent of the International Prognostic Index.

Conclusions Prognostication based on bone marrow involvement cytomorphology is a useful indicator of progression-free survival and overall survival, independent of the International Prognostic Index score, in DLBCL patients. Accurate staging based on morphology should thus be included in bone marrow examinations of such cases.