Location-specific analysis of clinicopathological characteristics and long-term prognosis of primary gastrointestinal diffuse large B-cell lymphoma.

Primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL) is the most common lymphoma in the gastrointestinal tract, yet research on its clinicopathological characteristics and long-term prognosis across different sites is lacking. This study aims to assess these aspects in PGI-DLBCL patients using data from the Surveillance, Epidemiology, and End Results (SEER) database. Patients diagnosed with PGI-DLBCL between 2000 and 2021 were extracted from the SEER database. The clinicopathological characteristics of PGI-DLBCL in the stomach, small intestine, and colorectum were compared using Chi-square tests, and overall survival (OS) as well as cancer-specific survival (CSS) were evaluated using Kaplan-Meier curves and Cox regression analysis. A total of 10,935 patients were enrolled, with the stomach being the most prevalent site (53.3%), followed by the small intestine (26.3%) and colorectum (20.5%). Gastric PGI-DLBCL patients had higher proportions of elderly, females, and stage III/IV disease, primarily treated with chemotherapy. Patients with small intestine and colorectal PGI-DLBCL showed significantly better OS (HR 0.91, 95% CI 0.88-0.98, P = 0.021; HR 0.89, 95% CI 0.82-0.95, P < 0.001) and CSS (HR 0.93, 95% CI 0.81-0.98, P = 0.022; HR 0.86, 95% CI 0.78-0.94, P < 0.001) compared to gastric PGI-DLBCL. OS and CSS were similar between small intestine and colorectal PGI-DLBCL (P > 0.05). Five-year OS rates were 48.8%, 55.4%, and 52.8% for stomach, small intestine, and colorectum, respectively, with corresponding CSS rates of 61.5%, 65.6%, and 66.0%. Multivariate Cox regression identified age, race, marital status, tumor stage, location, and treatment as independent risk factors for OS and CSS. For gastric DLBCL, radiotherapy plus chemotherapy was most effective in improving prognosis, while surgery combined with chemotherapy was superior for small intestine and colorectal DLBCL. Gastric PGI-DLBCL has distinct clinicopathological features from small intestine and colorectum PGI-DLBCL, and may have a worse prognosis. However, chemoradiotherapy may enhance its outcome.