# Outcomes of patients aged 70 years or younger with aggressive ATL at core hospitals for ATL treatment in Tokyo

## TL;DR

This study examines the outcomes of younger aggressive ATL patients in Tokyo, showing that stem cell transplants significantly improve survival.

## Contribution

The study highlights the effectiveness of allogeneic hematopoietic stem cell transplantation in younger aggressive ATL patients in non-endemic regions.

## Key findings

- Allo-HSCT group had a 45.7% 3-year survival rate, while non-allo-HSCT group had 0%.
- Patients in remission before allo-HSCT had better survival (51.4% vs 27.3%).
- Relapse/progression and non-relapse mortality rates after allo-HSCT were 41.3% and 21.7%, respectively.

## Abstract

Adult T-cell leukemia-lymphoma (ATL) is one of the most intractable peripheral T-cell neoplasms caused by human T-cell leukemia virus type I (HTLV-1) infection. Recently, the incidence of HTLV-1 infection and ATL has increased in non-endemic metropolitan areas in Japan. This retrospective study evaluated the clinical features and outcomes of patients with aggressive ATL aged 70 years or younger treated at a core hospital in Tokyo between 2004 and 2016. The median follow-up was 124.4 months for survivors. Among the 71 patients, 46 (64.8%) underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). The 3 year overall survival rate was 45.7% in allo-HSCT group versus 0% in non-allo-HSCT group. Patients who achieved complete/partial remission before allo-HSCT had a significantly better survival rate than those with stable/progressive disease (51.4% vs 27.3%). The 2 year cumulative incidence of relapse/progression and non-relapse mortality after allo-HSCT was 41.3% and 21.7%, respectively. In this study, a large percentage of patients underwent allo-HSCT and achieved favorable outcomes. As cases continue to rise in metropolitan areas, core hospitals will play a critical role in ATL treatment.

The online version contains supplementary material available at 10.1007/s12185-025-04057-2.