Prognostic impact of concordant and discordant bone marrow involvement on diffuse large B-cell lymphoma

In diffuse large B-cell lymphoma (DLBCL), bone marrow (BM) involvement includes two types that are concordant involvement and discordant involvement. It has been reported that concordant BM involvement has a worse prognosis than discordant involvement in previous studies. However, the prognostic effects of concordant or discordant BM involvement on DLBCL still need further research. In this work, DLBCL cases with BM involvement were collected and analyzed to better reflect the prognostic implications of concordant and discordant BM involvement.

We reviewed the cases with newly diagnosed DLBCL and BM involvement from April 2018 to April 2022 in Northern Jiangsu People's Hospital. Overall survival (OS) and progression-free survival (PFS) were accessed by the Kaplan-Meier method and compared between groups by the log-rank test. A multivariate regression analysis based on Cox proportional hazard model was used to test the independent effect of each variable on survival.

In total, 32 patients were included and 15 (46.9%) patients had concordant BM involvement and 17 (53.1%) patients had discordant BM involvement. Compared with the discordant group, the concordant group tended to be older and had elevated lactate dehydrogenase level. The outcome of patients with concordant BM involvement was worse than the discordant subset, including OS (P=0.04) and PFS (P=0.03). Furthermore, the discordant BM involvement was excluded to acquire a BM-adjusted International Prognostic Index (IPI) score. The significance of BM-adjusted IPI scores to predict OS was improved greatly compared with the previous IPI scores (P=0.053 vs. P=0.16). Multivariate analysis showed that the BM-adjusted IPI was an independent predictor for OS [hazard ratio =3.406; 95% confidence interval (CI): 1.145-10.127; P=0.03].

These results highlight the requirement for identifying BM infiltration type accurately and then adjusting the IPI score by excluding discordant BM involvement since concordant involvement can partly predict a poor prognosis of DLBCL with BM involvement other than discordant involvement.