Background: Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin’s lymphoma (NHL) in Thailand. The gastrointestinal (GI) tract is among the most common sites for extranodal NHL. Studies showed that GI involvement had distinct characteristics, but overall survival compared with non-GI involvement were controversial. Our study aims to determine the overall survival between GI and non-GI DLBCL patients.

Materials and Methods: Based on Songklanagarind Hospital’s lymphoma registration database from 2008-2013. All patients ≥18 years with histologically confirmed DLBCL were retrospectively reviewed. Exclusion criteria were primary CNS/mediastinal lymphoma, coexisting with other malignancies, and who received treatment before the study period. Baseline clinical characteristics, treatment response, and overall survival were obtained and analyzed according to GI and non-GI involvement. Subgroups of primary and secondary GI DLBCL were categorized by Dawson’s criteria.

Results: A total of 455 patients were eligible, 89.23% were non-GI DLBCL and 10.77% were GI DLBCL. GI DLBCL patients had a lower hemoglobin level. The median survival of non-GI and GI groups were comparable (20.6 vs. 22.6 months). Among GI DLBCL, 73.5% were in secondary group. Primary GI DLBCL patients had a higher age, lower Ann Arbor staging, and a lower LDH level compared with the secondary group. The median survival of the primary group was insignificantly better than secondary group (73.4 vs. 13.3 months, p-value = 0.095).

Conclusions: Overall GI involvement in DLBCL patients was not correlated with poorer overall survival. But among GI DLBCL patients, primary GI DLBCL had distinct clinical characteristics and tended to have better survival than secondary group.