TREATMENT STRATEGIES AND PROGNOSTIC FACTORS OF PRIMARY GASTRIC DIFFUSE LARGE B CELL LYMPHOMA: A RETROSPECTIVE STUDY OF 303 CASES FROM CHINA LYMPHOMA PATIENT REGISTRY

Abstract

Introduction: Primary gastric diffuse large B cell lymphoma (PGDLBCL) is the common primary extranodal DLBCL, with higher incidence in Asian than in Western countries. However, the optimal treatment for PGDLBCL remains controversial. We thus conducted a retrospective analysis of 303 cases to evaluate present treatment strategies and prognostic factors of PGDLBCL. Methods: From three centers of the China Lymphoma Patient Registry (CLAP), 303 PGDLBCL cases from January 1994 to December 2015 were retrospectively analyzed. Patients were classified into four groups: chemotherapy (C, 192 cases), surgery (S, 21 cases), chemotherapy + surgery (C + S, 78 cases), and watch and wait (12 cases). Results: The 3-year progression-free survival (PFS) and 3-year overall survival (OS) of the entire cohort were 75.3% and 80.3% (median follow-up time: 42 months). PFS (p = 0.122) and OS (p = 0.451) were similar among the four treatment groups. In the chemotherapy-treated cohort, group C + S had higher PFS than group C (83.7% vs. 71.8%, p = 0.013). Its OS was also relative higher, even without statistical significance (86.6% vs. 78.5%, p = 0.097). The inclusion of radiotherapy during initial treatment (23 cases) in this cohort did not improve PFS (57.9% vs. 76.2%, p = 0.017) or OS (73.7% vs. 81.1%, p = 0.220). Rituximab did not show significant clinical benefit in our study (PFS: 78.1% vs. 71.1%, p = 0.205; OS: 83.9% vs. 75.7%, p = 0.052). Treatment-related complications included gastrointestinal bleeding (22 cases), perforation (4 cases), and obstruction (4 cases), which correlated with poorer outcomes (PFS: 50.7% vs. 78.1%, p = 0.005; OS: 59.2% vs. 83.3%, p < 0.001). Glucocorticoid in chemotherapy increased incidence of complications (p = 0.035). The univariate analysis revealed prognostic factors as age, Lugano stage, ECOG, B symptom, International Prognosis Index, LDH, HGB, ESR, β2-MG, lesion in cardia, prior gastrointestinal bleeding, and complications. The multivariate analysis showed that B symptom (Relative rate (RR) = 2.82, p = 0.016), lesion in cardia (RR = 2.86, p = 0.039), LDH (RR = 4.65, p < 0.001) and gastrointestinal bleeding before treatment (RR = 3.08, p = 0.005) were highly predictive for poor PFS, and the latter two factors also predicted poor OS (RR = 4.08, p = 0.004; RR = 3.18, p = 0.001). Conclusions: Our results indicated that chemotherapy + surgery is a considerable choice to improve the survival of PGDLBCL. The inclusion of radiotherapy during initial treatment did not improve survival in our study. Due to elevated risk of complication, glucocorticoid could be removed from chemotherapy. B symptom, lesion location, LDH, and gastrointestinal bleeding before treatment are independent predictors of poor outcomes. This retrospective, multicenter analysis provides the largest sample size study for PGDLBCL, but the future prospective trial is warranted. Keywords: extranodal lymphomas.