Clinicopathological analysis of primary refractory diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone chemoimmunotherapy

Background Approximately 15% of patients with diffuse large B-cell lymphoma (DLBCL) experience refractory or early relapsed disease after initial rituximab-containing chemoimmunotherapy is regarded as a primary refractory disease. Although the standard treatment for relapsed DLBCL is high-dose chemotherapy and autologous stem cell transplantation (HDC-ASCT), the efficacy of this approach for primary refractory DLBCL is not well understood. We aimed to investigate the clinicopathological characteristics and outcomes of patients with primary refractory DLBCL. Methods Sixty-nine consecutive patients with primary refractory DLBCL who were treated at our institution were categorized as partial responders (partial response to rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone [R-CHOP] or relapse within 6 months of R-CHOP) (n = 41) or primary progressors (no response to R-CHOP) (n = 28). Survival curves were constructed using the Kaplan-Meier method and compared using the log-rank test. Results At initial diagnosis, 70% of patients had Ann Arbor stage III/IV disease, 56% had non-germinal center B-cell-like type DLBCL, and 42% had double-expressor lymphoma (MYC and BCL2 expression). The 3-year overall survival rate was significantly poorer in the primary progressors group than in the partial responders' group (15% vs. 48%, p < 0.001). Four of 17 patients treated with HDC-ASCT were primary progressors; only one patient survived without relapse. Although double-expressor lymphoma status did not significantly impact overall survival among all patients (p = 0.794), it was identified as an independent poor prognostic factor in HDC-ASCT-treated patients (p = 0.002). Conclusions We identified a subgroup of patients with primary refractory DLBCL who may not benefit from current treatment strategies. Further treatment development is needed to improve the outcomes of these patients.