Cytogenetic and molecular characteristics and outcomes of adult patients with early T‐cell precursor acute lymphoblastic leukemia

Early T‐cell precursor acute lymphoblastic leukemia (ETP‐ALL) is a recently identified high‐risk subgroup of T‐cell ALL in children. However, there have been conflicting reports and limited data have been reported in adult patients. We retrospectively analyzed the cytogenetic and molecular characteristics and long‐term survival outcomes of adult patients with ETP‐ALL versus non‐ETP‐ALL. We analyzed 58 patients (median age, 35 years [range, 18–76 years]) with newly diagnosed T‐cell ALL who received a uniform remission induction and consolidation chemotherapy with suitable samples for genetic analyses. If a donor was available, all patients were recommended allogeneic hematopoietic cell transplantation (allo‐HCT) for post‐remission therapy. Out of 58 patients, 21 (36.2%) had ETP‐ALL. Patients with ETP‐ALL were older and had a higher proportion of complex karyotype than non‐ETP‐ALL. Additionally, more DNMT3A mutations were detected in ETP‐ALL, whereas FBXW7 mutations and CDKN2A/CDKN2B deletions were found nearly exclusively in non‐ETP‐ALL. The overall complete remission (CR) rates were not different between ETP‐ALL (95.2%) and non‐ETP‐ALL (81.1%) and subsequent allo‐HCT proceeding rates in CR1 were 61.9% for ETP‐ALL and 43.2% for non‐ETP‐ALL, respectively. The overall prognosis of patients with T‐ALL was poor that estimated 5‐year overall survival (OS) was 33.3% for ETP‐ALL and 29.5% for non‐ETP‐ALL. In a subgroup analysis of patients treated with allo‐HCT in CR1 (n = 29), 5‐year OS was 53.8% for ETP‐ALL and 55.4% for non‐ETP‐ALL. Our data showed molecular characteristics of ETP‐ALL and non‐ETP‐ALL and revealed that intensive chemotherapy followed by allo‐HCT for post‐remission therapy can contribute to preserved survival outcome of adult patients with ETP‐ALL.