Diffuse large B call lymphoma is the most common subtype of non-Hodgkin lymphoma, accounting for about 30% of patients overall. In recent years, we have learned that there are several different subsets of DLBCL that have been identified either at the clinical or biologic level. Traditionally DLBCL subgroups were defined by features such as the international prognostic index, or through clinical presentations – such as mediastinal, testicular or other body site – which have been associated with distinct outcomes and for which individualized treatment may be appropriate. We now know that the cell of origin for diffuse large B cell is relevant to biology and outcome – and that if the tumor cells originate from germinal center or activated B cells distinct biologic pathways may be relevant, leading to targeted therapies. Additionally, “double hit” lymphomas have a less favourable outcomes in general with standard DLBCL treatment.
The current standard therapy for DLBCL for most patients is R-CHOP. Ongoing studies are comparing the infusional regimen R-EPOCH to R-CHOP and those results are eagerly awaited. In addition, molecularly targeted therapies such as lenalidomide or ibrutinib are being added to R-CHOP for specific subsets of patients and randomized trials are underway. However, it is important to note that the process of identifying patient subsets using biomarker tests can result in a selection bias (excluding less favorable patients that cannot wait for such screening to occur). Ongoing efforts are assessing the role of new approaches in DLBCL so that we can move to a point where are treatments can be more specific, have greater efficacy and less toxicity.