Nationwide surveys of adult T-cell leukemia/lymphoma (ATL) have played an important role in helping us to understand the pathophysiology of this disease and analyze its prognosis in Japan. Classifications of clinical subtypes have been proposed based on the results of nationwide surveys of patients with ATL diagnosed in the 1980s. This article highlighted the classification and prognosis of ATL based on different surveys and focused on the comparison of data derived from the available surveys. The 11th nationwide hospital-based survey was conducted in patients with ATL diagnosed in 2010-2011 using the same method as that used in the 1980s survey. The median age of disease onset was 68 years, which was increased compared with previous surveys. While median survival of patients with the acute and lymphoma types had not improved much since the 1980s, the 4-year survival rate was higher. Little improvement in the prognosis was observed for the chronic and smoldering types. The 12th nationwide survey of patients with ATL diagnosed in 2012-2013 also showed an increase in age at onset. Further epidemiological research that includes more cases is needed to deepen our understanding of the actual state of treatment and prognosis of this disease.
Keywords: adult T-cell leukemia/lymphoma; clinical subtype; nationwide survey; prognosis.