Immunohistochemi-NCCN Diffuse Large B-Cell Lymphoma Version 1 . 2016 Clinical Practice Guidelines in Oncology

Diffuse large B-cell lymphomas (DLBCL) are now considered a heterogeneous group of distinct molecular subtypes (germinal center B-cell DLBCL, activated B-cell DLBCL, and primary mediastinal large B-cell lymphoma (PMBL) with varied natural history and response to therapy. In addition, a subset of patients with DLBCL have concurrent MYC and/or BCL2 gene rearrangements (double-hit lymphomas; DHL) and others have a dual expression of both MYC and BCL2 proteins (double-expressing DLBCL; DEL). The standard of care for the treatment of patients with PMBL, DHL, or DEL has not been established. Adequate immunophenotyping and molecular testing (in selected circumstances) are necessary for the accurate diagnosis of different subtypes of DLBCL. The NCCN Guidelines included in this issue, part of the NCCN Guidelines for non-Hodgkin’s lymphomas, address the diagnosis and management of DLBCL and its subtypes. J Natl Compr Canc Netw 2016;14:196–231 NCCN Categories of Evidence and Consensus Category 1: Based upon high-level evidence, there is uniform NCCN consensus that the intervention is appropriate. Category 2A: Based upon lower-level evidence, there is uniform NCCN consensus that the intervention is appropriate. Category 2B: Based upon lower-level evidence, there is NCCN consensus that the intervention is appropriate. Category 3: Based upon any level of evidence, there is major NCCN disagreement that the intervention is appropriate. All recommendations are category 2A unless otherwise