Non-Hodgkin lymphoma in the Far East: review of 730 cases from the international non-Hodgkin lymphoma classification project.

Abstract

Large and systematic studies of non-Hodgkin lymphoma (NHL) in the Far East (FE) with good comparative data are scarce in the literature. In this study, five expert hematopathologists classified 730 consecutive cases of newly-diagnosed NHL from four sites in the FE (excluding Japan) using the World Health Organization classification. The results were compared to 399 cases from North America (NA). We found a significantly higher male to female ratio in the FE compared to NA (1.7 versus 1.1; p < 0.05). The median ages of patients with low-grade (LG) and high-grade (HG) B-NHL in the FE (58 and 51years, respectively) were significantly lower than in NA (64 and 68years, respectively). The FE had a significantly lower relative frequency of B-NHL and a higher frequency of T-NHL (82 vs. 18%) compared to NA (90.5 vs. 9.5%). Among mature B cell lymphomas, the FE had a significantly higher relative frequency of HG B-NHL (54.8%) and a lower frequency of LG B-NHL (27.2%) than NA (34.3 and 56.1%, respectively). Diffuse large B cell lymphoma was more common in the FE (49.4%) compared to NA (29.3%), whereas the relative frequency of follicular lymphoma was lower in the FE (9.4%) compared to NA (33.6%). Among T-NHL, nasal NK/T cell NHL was more frequent in the FE (5.2%) compared to NA (0%). Peripheral T cell lymphoma was also more common in the FE (9.1%) than in NA (5.3%). Further epidemiologic studies are needed to better understand the pathobiology of these differences.