Transformation in follicular lymphoma: biology, prognosis, and therapeutic options

The transformation of follicular lymphoma to an aggressive lymphoma is a well-recognised complication that occurs at a rate of approximately 3 % a year for the first 10 years of observation. Transformation is accompanied by increased risk of refractoriness and a poor expectation of survival. Genetic and epigenetic triggers for transformation have been described. Prior to routine use of rituximab, transformed lymphoma was managed in a fashion similar to that for de novo diffuse large B-cell lymphoma, with generally poor results. Rituximab appears to have improved outcomes. Some centres, including our own, use high-dose chemotherapy with stem cell transplantation as consolidation for those with responsive disease. Here, we focus on transformed follicular lymphoma, and provide an overview of the current literature and our approach to management.