Increased incidence of adult T cell leukemia-lymphoma and peripheral T cell lymphoma-not otherwise specified with limited improvement in overall survival: a retrospective analysis using data from the population-based Osaka Cancer Registry.

Peripheral T cell lymphomas (PTCL) are a heterogeneous group of non-Hodgkin lymphomas with poor outcomes. Adult T cell leukemia-lymphoma (ATL) and PTCL-not otherwise specified (PTCL-NOS)-are 2 common mature T cell lymphomas in Japan. Since it is unclear whether novel agents and treatment strategies incorporating hematopoietic cell transplantation have contributed to improved clinical outcomes in the real world, we performed a retrospective analysis using data from the population-based Osaka Cancer Registry. From 1977 to 2014, 1274 and 1143 patients were diagnosed with ATL or PTCL-NOS, respectively. Recently, the incidence of both diseases has gradually increased, and the age at diagnosis has risen. The 3-year overall survival (OS) rates in ATL patients were 12.0% in era 1 (1977-1999), 12.4% in era 2 (2000-2008), and 17.5% in era 3 (2009-2014) (P < 0.001). The 3-year OS rates in PTCL-NOS patients were 27.6% in era 1, 36.2% in era 2, and 35.0% in era 3 (P = 0.049). In conclusion, the incidences of ATL and PTCL-NOS have been increasing, particularly in elderly individuals. Clinical outcomes have improved in recent decades but are still unsatisfactory in both diseases. Thus, effective new treatment strategies incorporating novel agents are needed to further improve clinical outcomes in patients with ATL and PTCL-NOS.