Nationwide survey of adult T-cell leukemia/lymphoma (ATL) in Japan.

In a nationwide survey of ATL in Japan, a total of 910 cases of ATL and 7,164 cases of B-NHL as a control disease, newly diagnosed from January 2006 to December 2007 (2 years), were enrolled from 156 hospitals. Male-female ratios were 1.16 for ATL and 1.22 for B-NHL. Among all ATL cases registered, 59.8% were from an HTLV-1 endemic area in Kyushu, and the ratio of ATL to B-NHL in this area was 1 to 3, while that in a non-endemic area in Tokyo was 1 to 40. Compared to previous nationwide studies, the age of ATL patients shifted toward older ages and the mean age gradually increased from 52.7 years in the first survey (cases before 1980) to 61.1 years in the ninth survey (1996-1997) and, finally, to 66.0 years in the present study (range: 19 to 94, median: 67). On subtype classification, 46.7% were classified as the acute type, 34.8% the lymphoma type, 10.3% the smoldering type, and 8.2% the chronic type, and the rate of the acute type decreased with an increase in the lymphoma type compared to that in previous studies. An increase in the mean age is explained by the high HTLV-1 prevalence in elderly people over 64 years old in endemic areas (20%), and by the continual development of ATL from this large pool of HTLV-1 carriers. According to mortality statistics from the Ministry of Health, Labor and Welfare in Japan, approximately 1,000 people die annually from ATL, a statistic that has not changed at least for the past decade.