Epidemiological and clinical features of adult T-cell leukemia-lymphoma in Japan, 2010-2011: A nationwide survey

Abstract

Adult T-cell leukemia-lymphoma (ATL) is a mature T-cell malignancy associated with human T-cell leukemia virus type 1 (HTLV-1) infection. Japan is the most endemic country for HTLV-1 and ATL in the world. Recent nationwide studies of Japanese blood donors reported that HTLV-1 carriers spread from endemic areas to non-endemic areas. Therefore, the latest information on nationwide epidemiological and clinical data for ATL is necessary to guide clinical practice. We undertook a multicenter, hospital-based survey of newly diagnosed ATL patients from 2010 to 2011. A total of 996 patients with ATL were registered from 126 hospitals across Japan. Of those, 922 (487 men and 435 women) were included in the analysis. The median age at diagnosis was 68 years (interquartile range, 60-75 years). Overall, 67.2% of ATL was diagnosed in the Kyushu-Okinawa area. The most common subtype was acute (49.5%), followed by lymphoma (25.7%), chronic (14.2%), and smoldering (10.6%). Lymphoma type was more prevalent in men (60%), whereas chronic was more prevalent in women (60%). Half of patients with lymphoma type were aged over 70 years, whereas one-third of patients with the chronic type were aged under 60 years. All of these characteristics were different from those of the previous nationwide surveys in the 1980s and 1990s. This survey clarified that half of current patients with ATL are aged over 68 years who were unable to receive intensive cytotoxic therapies. New less toxic agents for aged patients and further strategies to prevent the development of ATL from HTLV-1 carrier status are needed.

Keywords: ATL; Adult T-cell leukemia-lymphoma; HTLV-1; human T-cell leukemia virus type 1; nationwide survey.

Figure 1

(a) Flowchart of the study of epidemiological and clinical features of adult T‐cell leukemia–lymphoma (ATL) in Japan, 2010–2011. HTLV‐1, human T‐cell leukemia virus type 1. (b) Distribution of age at diagnosis by sex. F, female; M, male. (c) Distribution of age at diagnosis by ATL subtype based on the central reviewers’ classification based on the Shimoyama classification.19 (d) Changes in the proportion of patients in each age category from years 1988–1989,14 1996–1997,18 to 2010–2011 (current study). (e) Changes in the proportion of ATL subtype from years 1992‐1993,16 1994‐1995,17 2006–2007,20 to 2010–2011 (current study).