Non-Hodgkin’s Lymphoma
Generally, two broad categories of lymphomas are recognized: Hodgkin’s lymphoma (often called Hodgkin’s disease) and non-Hodgkin’s lymphoma. Hodgkin’s disease is characterized by a specific type of cell known as the Reed-Sternberg cell. Non-Hodgkin’s lymphomas comprise all lymphomas that are not characterized by Reed-Sternberg cells.
Over the past few decades, many case-control studies have been conducted of persons diagnosed with (or deceased from) non-Hodgkin’s lymphoma to determine causal factors for this disease. Most of these studies reported increased risks of non-Hodgkin’s lymphoma for organic solvent exposure, but until recently few studies specifically analyzed whether exposure to aromatic hydrocarbons or benzene specifically is associated with an increased risk of non-Hodgkin’s lymphoma.
Since 2000, four case-control studies have been conducted which specifically analyze whether exposure to benzene or aromatic hydrocarbons is associated with an increased risk of non-Hodgkin’s lymphoma. All four of these studies provide strong evidence of such a causal association. Additionally, four earlier case-control studies also provide evidence of a causal association specifically between benzene and non-Hodgkin’s lymphoma.