Early response and outcomes of bone marrow to chemotherapy in T-Cell Acute Lymphoblastic Leukemia.

Objectives: To evaluate the outcomes (relapse and mortality rate) and response of the bone marrow in early stages after combination chemotherapy in patients with T-cell Acute Lymphoblastic Leukemia (T-ALL). Methods: A descriptive cross-sectional study was conducted at King Fahad Medical City, from January 2021 to December 2022, to evaluate bone marrow findings at the time of diagnosis and post-chemotherapy in 26 patients diagnosed with T-ALL. The study included all patients diagnosed with T-ALL of any age group during the study period. The patients' bone marrows were examined at 0 days of treatment (diagnosis work-up), followed by examination at day 15 post induction therapy, and day 30 after treatment. Results: In this study, 26 cases of T-lymphoblastic leukemia were analyzed. The mean age at diagnosis was 15.69±14.28 years, and eight cases had central nervous system involvement. The majority of cases (88.5%) were positive for Cytoplasmic-CD3 and CD7. Positive findings by fluorescence in situ hybridization (FISH) were: T cell receptor (TCR) α/δ in 6 (23.1%) of the patients, CDNK2A/CEP9 in five (19.2%), and TRCB in one (3.8%). Examination of the bone marrow on day 15 revealed a decrease in blasts to ≤1% in nine patients, and to ≤1% in 19 patients on day 30 post-therapy. Relapse was recorded in five (19.23%) patients. Three (11.53%) patients did not survive during treatment, of which two were <10 years old. The relapse rate for T-ALL was 19.23%, with an overall survival rate of about 64%. The overall mortality rate was 11.53%. Conclusion: The relapse rate for T-ALL in our study was approximately 19%, but the mortality rate was 11.5%. A substantial decrease in blast percentages was observed, suggesting a favorable initial reaction of the bone marrow to the combined chemotherapy. This suggests that the use of aggressive and more effective chemotherapy has led to better outcomes.