Outcome of allogeneic hematopoietic cell transplantation in patients with adult T‐cell leukemia

Adult T‐cell leukemia/lymphoma (ATL) is an aggressive peripheral T‐cell neoplasm, and the outcome of patients with ATL after chemotherapy is poor. Allogeneic hematopoietic stem‐cell transplantation (allo‐HSCT) is a curative treatment modality for ATL, and four factors, namely, age > 50 years, male recipient, lack of complete remission at transplantation, and transplantation of cord blood, were previously shown to be associated with poor survival. We retrospectively analyzed the outcome of 21 patients with ATL who had undergone allo‐HSCT at our hospital during a 3‐year period. Of 21 patients, all had at least one of the above risk factors, and 18 had two or more. With a median follow‐up of 19.7 months for living patients, the 1‐ and 2‐year overall survival (OS) rates after transplantation were 34% and 27%, respectively. All relapse/progression events occurred within 1 year after allo‐HSCT, and the cumulative incidence of relapse/progression at 1 year after allo‐HSCT was 46.9%. The 100‐day and 1‐year nonrelapse mortality (NRM) rates were 19% and 42%, respectively. No significant difference in OS was observed between myeloablative and reduced‐intensity conditioning regimens. The 3‐year OS (27%) of ATL patients who received allo‐HSCT and who had at least one adverse factor was somewhat poorer than the 3‐year OS of 33% identified in a nationwide study of allo‐HSCT in ATL patients in Japan. The high relapse/progression and NRM rates are major problems to be solved to achieve better outcome.