A clinicopathologic study of primary mediastinal large B-cell lymphoma (MLBCL) at a single institution in Japan

Abstract

6686 Background: Numerous clinicopathologic studies of MLBCL have been reported from US and European countries; however, only a few case-series of at most 10 cases are available from Japan and other East Asian countries. Recent investigations revealed that the molecular signature of MLBCL differs from that of other types of diffuse large B-cell lymphoma and shares features with Hodgkin's lymphoma (HL). Considering the low incidence of HL in East Asia, the incidence and clinical features of MLBCL patients (pts) might be also different. To further clarify the clinicopathologic features of pts with MLBCL in Japan, we conducted a retrospective study. Methods: A total of 28 pts with MLBCL who were diagnosed and treated at our institution between 1982 and 2002 were analyzed. Results: The median age was 37 years (range, 18–80). Sixteen male pts showed a bimodal age distribution with one peak at 30–50 years of age and another peak in the 60s, whereas 12 female pts showed a single peak at 20–40 years. The median follow-up duration in all pts was 21 months and that in surviving pts was 35.7 months. Only 13 pts (46%) achieved complete response (CR) by initial treatments, mostly by CHOP-like regimens followed by radiotherapy. The estimated 3-year disease-free survival of the 13 pts who achieved CR was 66%; however, the estimated 3-year overall and failure-free survivals for all 28 pts were 32% and 33%, respectively. A multivariate analysis revealed that age ≥ 40 and PS > 1 were independent factors significantly associated with shortened survival. Conclusions: The clinicopathologic features of Japanese pts with MLBCL might differ from those in US and European countries, especially with respect to male/female ratio, age distribution and unfavorable clinical outcome. Further large-scale studies, including molecular diagnosis and new approaches to the optimal management, are warranted. No significant financial relationships to disclose.