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.