Outcomes of primary gastrointestinal diffuse large B cell lymphoma in the rituximab era.

BACKGROUND

Primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL) constitutes 30%-40% of primary extranodal lymphomas. While rituximab has significantly improved survival in nodal DLBCL, its impact on the prognosis of PGI-DLBCL remains inadequately defined. This study aimed to compare the survival outcomes of PGI-DLBCL patients between the pre-rituximab and rituximab eras.

METHODS

We identified all PGI-DLBCL cases from the Surveillance, Epidemiology, and End Results (SEER) registry (1975-2015). Patients were categorized into pre-rituximab (diagnosed before 2006) and rituximab-era (diagnosed in or after 2006) groups. Overall survival (OS) and lymphoma-specific survival (LSS) were compared between the two groups.

RESULTS

Among 2780 patients, median age was 68 years; 72.2% had stage I/II disease. The rituximab-era group showed significantly longer median OS (119 months vs. 43 months, p < 0.0001). Median LSS was not reached in the rituximab era versus 115 months in the pre-rituximab group (p < 0.0001), with an 11-year LSS rate of 58%. Multivariable analysis confirmed that the rituximab era, younger age, early stage, and chemotherapy were associated with better OS and LSS.

CONCLUSIONS

PGI-DLBCL represents a significant subset of non-Hodgkin lymphomas and is the most prevalent type within the gastrointestinal tract. Younger age, female, Asian, marital status, early-stage and with chemotherapy, as well as the period of lymphoma diagnosis (rituximab era), are associated with better prognosis.