Epidemiology and Prognosis of T-Cell Lymphoma

NHL incidence rates rose steadily in the second half of the twentieth century. This observation motivated the conduct of numerous large-scale population-based epidemiologic studies of NHL in the last decade whose goals were to understand the rising rates and to uncover the etiology of NHL and its heterogeneous subtypes. In these studies, however, T-cell lymphomas and its subtypes are underrepresented due to the low incidence of disease and the relatively small proportion of NHL cases that are considered T-cell lymphomas. Like B-cell lymphomas, T-cell lymphomas comprise multiple subtypes with different incidence rates and patterns that likely re fl ect their distinct etiologies (e.g., mycosis fungoides and adult T-cell leukemia/lymphoma (ATL)). In recent years, the incidence rates of many B-cell lymphomas have begun to decline in the United States (US). In contrast, incidence rates for T-cell lymphomas have continued to rise. With consortial efforts and multidisciplinary approaches to epidemiologic research, the major hurdles for uncovering T-cell lymphoma risk factors may fi nally be surmountable.