Extranodal site of diffuse large B‐cell lymphoma and the risk of R‐CHOP chemotherapy resistance and early relapse

Background About 20%‐30% of diffuse large B‐cell lymphoma (DLBCL) patients experience early disease progression despite R‐CHOP chemotherapy treatment. Revised international prognostic index (R‐IPI) score could risk stratify DLBCL patients but does not identify exactly which patient will be resistant to R‐CHOP therapy or experience early relapse. Aims of the Study To analyse pre‐treatment clinical features of DLBCL patients that are predictive of R‐CHOP therapy resistance and early disease relapse after R‐CHOP therapy treatment. Methods Used to Conduct the Study A total of 698 lymphoma patients were screened and 134 R‐CHOP‐treated DLBCL patients were included. The Lugano 2014 criteria was applied for assessment of treatment response. DLBCL patients were divided into R‐CHOP resistance/early relapse group and R‐CHOP sensitive/late relapse group. Results of the Study 81 of 134 (60%) were R‐CHOP sensitive/late relapse, while 53 (40%) were R‐CHOP resistance/early relapse. The median follow‐up period was 59 months ± standard error 3.6. Five‐year overall survival rate of R‐CHOP resistance/early relapse group was 2.1%, while it was 89% for RCHOP sensitive/late relapse group. Having more than one extranodal site of DLBCL disease is an independent risk factor for R‐CHOP resistance/early relapse [odds ratio = 5.268 (1.888‐14.702), P = .002]. The commonest extranodal sites were head and neck, gastrointestinal tract, respiratory system, vertebra and bones. Advanced age (>60 years), advanced disease stage (lll‐lV), raised pre‐treatment lactate dehydrogenase level, bone marrow involvement of DLBCL disease high Eastern Cooperative Oncology Group status (2‐4) and high R‐IPI score (3‐5) showed no significant association with R‐CHOP therapy resistance/early disease relapse (multivariate analysis: P > .05). Conclusion and Clinical Implications DLBCL patients with more than one extranodal site are 5.268 times more likely to be R‐CHOP therapy resistance or experience early disease relapse after R‐CHOP therapy. Therefore, correlative studies are warranted in DLBCL patients with more than one extranodal site of disease to explore possible underlying mechanisms of chemoresistance.