Outcomes and toxicities in patients with diffuse-large B cell lymphoma involving the gastrointestinal tract and digestive organs

BackgroundDiffuse large B-cell lymphoma (DLBCL) involving the gastrointestinal (GI) organs is rare, and real-world outcomes after combined modality therapy (CMT) with systemic therapy (ST) and radiotherapy (RT) are not well-characterized, particularly in the contemporary era. We characterized outcomes in a large cohort of GI-DLBCL patients treated with ST alone or CMT.MethodsPatients with GI-DLBCL treated at a single institution were retrospectively reviewed. Kaplan-Meier and Cox regression models estimated survival. Multivariable analyses were conducted using the Cox proportional hazards model.ResultsOf 204 patients, gastric involvement was most common (63%). Most presented with early-stage disease (61%). All patients received ST and 65 patients (32%) received RT, 88% as part of first-line CMT. Median dose was 36 Gy (IQR 30.6–39.6) in 18 fractions (IQR 17–22). Median follow-up was 46 months. Five-year overall survival (OS) and progression-free survival (PFS) was 88% and 84%, respectively; complete response (CR) rate was 82%. Improved OS associated with low IPI (p=0.001), fewer chemotherapy lines (p0.25). Only early stage and CR correlated with improved OS on multivariable analysis. Stomach-directed RT vs. RT to other sites correlated with improved PFS and OS (p