Purpose: Some diffuse large B-cell lymphomas (DLBCL) present at diagnosis with associated morphologic features of small B-cell non-Hodgkin's lymphoma (NHL) and may arise from the transformation of a previously unknown indolent low-grade lymphoma. The characteristics and prognosis of these particular DLBCL are not well known.
Patients and methods: The strict morphologic review of consecutive DLBCL patients diagnosed over 12 years in our department (Hematology Department, Centre Hospitalier Lyon-Sud, Lyon, France) allowed to retrieve 60 DLBCL that could be have occurred from the transformation of marginal zone B-cell NHL (32 patients), follicular NHL (22 patients), and small lymphocytic NHL (6 patients). We compared them to 180 matched patients of de novo DLBCL.
Results: Patients median age was 55 years and presented the following clinical characteristics: poor performance status in 33%, disseminated disease in 97%, more than one extranodal site in 50%, and increased lactate dehydrogenase level in 55%. Complete remission with multidrug chemotherapy regimens was achieved in 60% of the patients, but 48% relapsed: 28% with aggressive and 20% with indolent histology, respectively. Overall survival (OS) and freedom-from-progression rates at 5 years were 57% and 33%, respectively. The matched-control analysis showed that patients with transformed NHL at diagnosis had lower complete response to chemotherapy (P = .004) and higher progression rate (P = .03), whereas no difference was observed in OS (P = .21).
Conclusion: Compared to de novo DLBCL, transformed NHL at diagnosis have similar overall survival but lower complete response to initial treatment and higher risk of indolent relapses.