Treatment Strategies and Prognostic Factors of Primary Gastric Diffuse Large B Cell Lymphoma: A Retrospective Multicenter Study of 272 Cases from the China Lymphoma Patient Registry

: Background: The respective and combinatorial roles of surgery, Rituximab and chemotherapy in primary gastric diffuse large B cell lymphoma (PGDLBCL) therapy remained unclear. The purpose of the study was to evaluate present treatment strategies and prognostic factors of PGDLBCL. Methods: 272 cases (from 1994-1 to 2015-12) were retrospectively analyzed. According to the therapy regimen, patients were classified into four groups: chemotherapy (C), chemotherapy + surgery (C+S), Rituximab + chemotherapy (R+C), and Rituximab + chemotherapy + surgery (R+C+S). Results: The 3-year progression-free survival (PFS) and 3-year overall survivals (OS) of the entire cohort were 77.0% and 81.2% respectively (median follow-up time: 44.3 months). Survival of surgery-treated patients was superior to the survival of those receiving drug therapy alone (PFS: 82.6% vs. 74.7%, p=0.015; OS: 87.8% vs. 78.6%, p=0.036). Rituximab showed significant clinical benefit in OS (87.1% vs. 75.0%, p=0.007), especially in advanced-stage or high risk (IPI 3-5) patients. Group C had the lowest PFS and OS among the four groups, while the survival of other three groups were similar (Group C vs. Group C+S vs. Group R+C vs. Group R+C+S: 3-year PFS: 67.2% vs. 81.4% vs. 81.2% vs. 81.8%, p=0.002; 3-year OS: 68.4% vs. 85.4% vs. 87.2% vs. 88.6%, p<0.001). Multivariate analysis showed that IPI and therapy regimens were highly predictive for both PFS and OS. Conclusions: Our results suggested that the combinations of chemotherapy and surgery, or chemotherapy and Rituximab, are superior to other treatment strategies for PGDLBCL. IPI and therapy regimens are independent predictors of outcomes. Future prospective trial is warranted.