Clinical characteristics and prognosis of patients with co-existing follicular lymphoma and diffuse large B-cell lymphoma components in rituximab era.

Objective: This single-centre study aimed to determine the clinicopathological characteristics and prognosis for patients with co-existing FL and DLBCL components (FL/DLBCL).

Methods: We retrospectively analysed the clinical characteristics and prognosis of patients diagnosed with FL/DLBCL (n = 56) and with pure FL (n = 260) or de novo DLBCL (n = 812) (controls) between January 2013 and December 2021.

Results: The median age of patients with FL/DLBCL was 52 years. The amount of the DLBCL component ranged from 5 to 95%. Among the 56 FL/DLBCL cases analysed, 67.9% were of germinal centre B-cell (GCB) origin, 26.8% non-GCB origin, and 5.3% were unclassified. The clinical features of patients with FL/DLBCL were intermediate, falling between those of FL and DLBCL. Propensity-score matching was performed for patients with similar baseline characteristics who were receiving the rituximab plus cyclophosphamide, doxorubicin or epirubicin, vindesine, and prednisone (R-CHOP) regimen. Patients with FL/DLBCL showed inferior outcomes compared to those with FL, with a lower complete remission (CR) rate, progression-free survival (PFS), and overall survival (OS). Bone marrow involvement and B symptoms were identified as independent adverse prognostic factors for PFS among patients with FL/DLBCL. Patients with FL/DLBCL presented a lower CR rate and PFS but similar OS to those with DLBCL when receiving the R-CHOP regimen.

Conclusions: Patients with FL/DLBCL showed inferior treatment response and survival than those with pure FL and had a lower CR rate and PFS, but similar OS to those with DLBCL in the rituximab era.