Radioimmunotherapy in non-Hodgkin lymphoma: Prediction and assessment of response.

Non-Hodgkin lymphoma (NHL) is one of the most common malignancies and a major cause of morbidity and mortality. Radioimmunotherapy (RIT) is a novel modality for treating NHL which offers the combined use of monoclonal antibodies for specific targeting of malignant cells and radiation for killing these cells. Despite the promising results favoring RIT in several clinical studies in different target populations and NHL types, Food and Drug Administration (FDA) approval for RIT agents is restricted to a limited number of indications and agents, maybe because of several ambiguities that still exist in the field. One of these ambiguities are the lack of evidence-based prognostic factors that determine what patient population would benefit most from RIT, which is essential to know in order to optimize the efficacy and safety of treatment with RIT. As well as selecting the best patient population for RIT, it is important to assess the response to RIT in order to provide further treatment strategies or avoid unnecessary therapies and diagnostic procedures. In this review we have explored the details of how to predict the efficiency of RIT based on various prognostic factors that have been investigated in the evidence, and also discussed the proposed methods and timing schedules for assessing the response to RIT. We have also pointed out the ambiguities in the aforementioned topics, which call for more investigation.