The impact of initial tumor bulk in DLBCL treated with DA-EPOCH-R vs. R-CHOP: a secondary analysis of alliance/CALGB 50303.

The ideal treatment paradigm for bulky diffuse large B-cell lymphoma (DLBCL) remains uncertain. We investigated the impact of tumor bulk in patients treated with systemic therapy alone through Alliance/CALGB 50303. Data from this trial were obtained from the National Cancer Institute's NCTN/NCORP Data Archive. The study assessed the size of nodal sites and estimated progression-free survival (PFS) using Cox proportional hazards models. Stratified analysis factored in International Prognostic Index (IPI) risk scores. Out of 524 patients, 155 had pretreatment scans. Using a 7.5 cm cutoff, 44% were classified as bulky. Bulk did not significantly impact progression-free survival (PFS), whether measured continuously or at thresholds of >5 or >7.5 cm (p = 0.10-p = 0.99). Stratified analyses by treatment group and IPI risk group were also non-significant. In this secondary analysis, a significant association between bulk and PFS was not identified.