Relevance of prognostic index with β2-microglobulin for patients with diffuse large B-cell lymphoma in the rituximab era

Background The International Prognostic Index (IPI) has been a useful tool for predicting the prognosis of aggressive non-Hodgkin lymphoma in the last 20 years. Herein, we aimed to develop a new prognostic model for diffuse large B-cell lymphoma (DLBCL) in the rituximab era. Methods Between March 2004 and June 2012, patients with DLBCL treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone chemotherapy regimen were identified in the database of the Asan Medical Center (AMC) Lymphoma Registry. The primary and secondary endpoints were a new prognostic index for DLBCL and validation of the National Comprehensive Cancer Network-International Prognostic Index in our cohort, respectively. Results The AMC cohort comprised 621 patients. The median follow-up duration was 43.3 months (range, 6.2-122.5 mo). Univariate analysis revealed that age (≤60 vs. >60 yr), lactate dehydrogenase (LDH; within normal vs. increased), Eastern Cooperative Oncology Group performance status (ECOG PS; 0 or 1 vs. ≥2), advanced stage (Ann Arbor stage I/II vs. III/IV), extra-nodal involvement (≤1 vs. >1), B symptoms (no vs. yes), and beta-2 microglobulin (β2MG, ≤2.5 vs. >2.5) can be used to predict overall survival (OS). In multivariate analysis, only age, LDH, ECOG performance status, and β2MG were significantly associated with OS, and we developed a new prognostic model with these 4 factors. The new prognostic model showed better discriminative power compared with the classic IPI. Conclusion Our new prognostic index model for DLBCL in the rituximab era has good discriminative power and is convenient to use.