Diffuse Large B-Cell Lymphoma (DLBCL) Patients with Composite Histology Have Improved Early Outcome Compared to De Novo DLBCL When Treated with R-CHOP

Abstract

Background: A significant percentage of DLBCL patients present with a composite histology, often seen as a node containing both follicular lymphoma and DLBCL or DLBCL in the node and discordant indolent lymphoma in the bone marrow. Literature from the pre-rituximab era suggests DLBCL patients with transformed lymphoma or composite histology have worse outcome than de novo DLBCL. Here we report on early events in a cohort of R-CHOP treated patients.Goal: To determine whether patients with composite lymphoma have an inferior event free survival (EFS) and overall survival (OS) compared to de novo diffuse large B-cell lymphoma when treated with R-CHOP.Methods: Newly diagnosed patients treated with an R-CHOP containing regimen were prospectively enrolled in our Lymphoma SPORE registry from 9/2002 through 6/2007. Pathology was centrally reviewed. All patients were followed for retreatment, disease progression, and death.Results: 401 DLBCL patients were enrolled; 14% (57/401) had a composite histology. 33 patients had DLBCL and another histology, predominantly follicular lymphoma (n=29), in the same node. 20 patients had a non-DLBCL histology in a distinct location from the DLBCL; this was primarily indolent lymphoma in the bone marrow (n=15). 4 patients had both. 19% (75/401) of patients died during follow-up and 30% (121/401) had an event (death due to any cause, progression, or retreatment). Median follow-up for living patients was 34 months (range, 5–73). Composite DLBCL patients had higher event-free (3 year EFS = 79%) and overall (3 year OS = 93%) survival then de novo DLBCL (3 year OS = 66%, 3 year EFS 79%), p=0.05 and p=0.005 respectively. These differences remained statistically significant after adjusting for the International Prognostic Index (IPI): EFS HR = 0.53, 95% CI: 0.29–0.97, p=0.02; OS HR=0.28, 95% CI: 0.10–0.76, p=0.002. OS and EFS for composite DLBCL more closely resembled R-CHOP treated grade III follicular lymphoma (A,B) from the same cohort (3 year EFS = 81%, 3 year OS = 93%). Improved outcome for composite DLBCL was consistent whether the additional histology was in the same node or distinct from the DLBCL.Conclusions: R-CHOP treated DLBCL patients with indolent discordant bone marrow involvement or other composite histology have improved early OS and EFS compared to de novo DLBCL. Further follow-up is needed to assess the long-term prognosis of composite DLBCL in the rituximab era.HistologyNAge >60Stage III/IVLDH >ULNPS >1>2 EN Sites3 YR EFS3 YR OSde novo DLBCL34458%56%56%17%22%66%78%Composite DLBCL5765%77%*34%*18%32%79%*93%** Denotes statistically significant difference at p=0.05 [Display omitted]