Clinical significance of bone marrow involvement as confirmed by bone marrow aspiration vs. Bone marrow biopsy in diffuse large B-cell lymphoma

Background: In diffuse large B-cell lymphoma (DLBCL), bone marrow (BM) involvement confirmed by BM biopsy confers a poor prognosis. However, in clinical practice, there may be disagreement in results between BM biopsy and BM aspiration in determination of BM involvement. It is unknown which of BM biopsy or BM aspiration better correlates with clinical outcome. Objective: To evaluate clinical outcome of BM involvement as confirmed by BM aspiration vs. confirmation by BM biopsy in patients with DLBCL. Material and Method: Clinical data, treatment, and outcome of 126 DLBCL patients with available BM aspirate slides who attended the Hematology Clinic at Siriraj Hospital between January 1, 2007 and December 31, 2009 were reviewed. BM aspirate slides were revised and interpreted by hematologists. Results: BM involvement was found in 12.7% (16/126) by BM biopsy and 24.6% (31/126) by BM aspiration. Regarding BM biopsy results, rates of complete remission (CR) among patients with unequivocal involvement, equivocal involvement, and without involvement were 75.0%, 57.1%, and 77.7%, respectively (p = 0.464). Two-year overall survival (OS) rates among the three groups were not significantly different (p = 0.663). Regarding BM aspiration results, CR rates among patients with unequivocal involvement, equivocal involvement, and without involvement were 80.6%, 75.8%, and 72.7% (p = 0.755). Two-year OS rates among the three groups were not significantly different (p = 0.118). In multivariate analysis, BM involvement as determined by either BM biopsy or BM aspiration was not associated with CR rate or 2-year OS rates. However, the International Prognostic Index (IPI) and use of rituximab were found to be significantly associated with CR rate and OS. Conclusion: In patients with DLBCL, BM involvement confirmed by either BM biopsy or BM aspiration appears not to influence the rate of complete remission or 2-year overall survival.