Abstract
BACKGROUND: Small intestine primary mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma (DLBCL) are relatively rare types of non-Hodgkin's lymphoma. This study aimed to analyze the clinical characteristics and long-term prognosis of these two diseases based on the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: Patients diagnosed with small intestine MALT and DLBCL from 2000 to 2021 were included. Propensity score matching (PSM) was used to minimize selection bias. The Kaplan-Meier method and Cox proportional hazards models were utilized to evaluate the effects of various clinical characteristics on overall survival (OS) and cancer-specific survival (CSS). RESULTS: A total of 2,748 patients were enrolled, including 2,362 with DLBCL and 386 with MALT. Compared to DLBCL patients, MALT patients were younger, had a higher proportion of females, and presented at earlier American Joint Committee on Cancer (AJCC) stages. Before PSM, the MALT cohort demonstrated significantly better OS [hazard ratio (HR) 0.54, 95% confidence interval (CI): 0.46-0.64, P<0.001] and CSS (HR 0.34, 95% CI: 0.26-0.45, P<0.001) than the DLBCL cohort. Specifically, 5-year OS rates were 80.1% for MALT and 57.6% for DLBCL, while 5-year CSS rates were 90.0% and 67.8%, respectively. Even after PSM, the MALT group maintained significantly superior OS (HR 0.55, 95% CI: 0.44-0.68, P<0.001) and CSS (HR 0.37, 95% CI: 0.26-0.52, P<0.001). Cox regression analysis identified age and AJCC stage as prognostic factors for OS in MALT patients, while race and AJCC stage were prognostic for CSS. For DLBCL patients, age, year of diagnosis, AJCC stage, chemotherapy, and marital status were significant prognostic factors for both OS and CSS. CONCLUSIONS: Patients with small intestine MALT lymphoma have a better prognosis than those with DLBCL, and AJCC staging is a significant prognostic factor, highlighting the importance of early diagnosis and treatment.