Prognostic Factors, FLT-3 Mutations, and Treatment Outcomes with Pediatric-Inspired Protocols in Adolescent and Young Adults and Adult Patients with Acute Lymphoblastic Leukemia.

INTRODUCTION

The treatment protocols of adolescent and young adult (AYA) patients with acute lymphoblastic leukemia (ALL) have evolved, with the advent of pediatric-based regimens, measurable residual disease monitoring, and mutation analysis. Among the latter, previous reports have identified FLT-3 mutations in up to 5% of pediatric patients; however, the full clinical significance of these mutations in the non-pediatric population is still uncertain.

METHODS

Our cohort includes AYA patients with ALL treated with the NY-II and BFM protocols at different time periods, allowing analysis of prognostic factors and survival outcomes. Additionally, we analyzed DNA samples for FLT-3 mutations, focusing on the potential prognostic implications and treatment responses within our cohort.

RESULTS

No significant differences were found in overall survival or progression-free survival between the two treatment protocols. However, a higher rate of hematopoietic stem-cell transplantation was noted in the NY-II patients. Older age and high WBC count at presentation were identified as adverse prognostic factors using multivariate analysis. FLT-3 mutations were identified in 4 patients (5%) of the cohort, with only 1 patient having FLT-3 internal tandem duplication mutation and 3 patients having FLT-3-tyrosine kinase domain mutations.

CONCLUSIONS

The low rate and variability of FLT-3 mutations in an Israeli cohort precludes broad conclusions regarding their prognostic significance. In our cohort, age and WBC count but not treatment protocol or FLT-3 mutations influenced survival.