Respective prognostic values of germinal center phenotype and early 18fluorodeoxyglucose-positron emission tomography scanning in previously untreated patients with diffuse large B-cell lymphoma

From the Departments of Clinical Hematology (JD, TEG, IG, CH), Pathology and INSERM U617 (PG, CC-B), Biostatistics (FH), Nuclear Medicine (EI, MM), and Radiology (AR) - H. Mondor Hospital, Paris XII University, Assistance Publique-Hôpitaux de Paris (AP-HP), Créteil, France; Departments of Clinical Hematology (CG) and Pathology (JB), St-Louis Hospital, Paris VII University, AP-HP, Paris, France Correspondence: Corinne Haioun, Service d’Hématologie Clinique, Hôpital H. Mondor, 51, Avenue du Maréchal de Lattre de Tassigny, 94010 Créteil, France. E-mail: corinne.haioun{at}hmn.aphp.fr Background and Objectives: Diffuse large B-cell lymphomas (DLBCL) have a variable outcome, and powerful methods of prognostication are needed in order to choose the best treatment for each patient. Immunophenotypic classification of the tumor as germinal center (GC) or non-germinal center-like (nGC) and early response evaluation with 18 fluorodeoxyglucose positron emission tomography ( 18 FDG-PET) scanning have been correlated with survival in DLBCL but the two methods have never been evaluated simultaneously in the same patient population. Our aim was to investigate their respective prognostic values in the same series of patients. Design and Methods: We investigated the expression of CD10, Bcl-6, and MUM1 in 81 patients with DLBCL evaluated early with 18 FDG-PET. The tumors were classified as GC or nGC using the algorithm of Hans et al . The results of both methods were correlated with the patients’ characteristics and survival. Results: CD10 was positive in 27/76 (36%), Bcl-6 in 43/74 (58%), and MUM1 in 33/73 (45%) interpretable cases. Thirty-eight (51%) were in the GC group, and 36 (49%) in the nGC group. With a median follow-up of 33 months, estimated 3-year event-free survival (EFS) of the whole population was 67%. There was no influence of GC/nGC phenotype on survival. Three-year EFS was 46% in the early PET-positive group versus 80% in the PET-negative group ( p =0.0003). Interpretation and Conclusions: The prognostic value of GC/nGC phenotype is not confirmed in this heterogeneous series, whereas early PET findings are confirmed to be a powerful predictor of outcome. The impact of treatment decisions based on early PET results should be evaluated. Key words: diffuse large B-cell lymphoma, germinal center, immunohistochemistry, PET scan, prognosis.