ASSOCIATION OF HYPERDIPLOIDY WITH REMISSION STATUS IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA AFTER INDUCTION THERAPY

Abstract

Objective: To determine the frequency of hyperdiploidy in childhood acute lymphoblastic leukemia (ALL) and its association with remission status after induction therapy.

Study Design: Observational study.

Place and Duration of Study: Department of Haematology, Armed Forces Institute of Pathology (AFIP) and Pediatric Oncology Department Combined Military Hospital (CMH) Rawalpindi, from Apr 2017 to Apr 2018.

Patients and Methods: All diagnosed cases of ALL between 1-12 years of age were selected by convenient nonprobability sampling. All other cases of leukemias including patients of acute undifferentiated leukaemia, acute myeloid leukaemia and patients of ALL who did not yield successful cytogenetic culture or those who died during the induction therapy were excluded from the study. Diagnosis of ALL was done on the basis of morphology, cytochemistry, immunophenotyping and cytogenetics. Cytogenetic analysis was done by using conventional Giemsa banding. Karyotypes were interpreted using the International System for Human Cytogenetic Nomenclature (ISCN). On the basis of cytogenetics two groups were made one with hyperdiploidy and another without hyperdiploidy. Hyperdiploidy was defined as chromosomes >46. All patients of childhood
ALL were treated with ‘UK ALL 2011’ protocol and their remission status was assessed after 1 month of induction therapy by bone marrow examination. Remission status of 2 groups of ALL with and without hyperdiploidy were compared by using chi square test

Results: Out of total 80 patients of ALL, 62 (77.5%) yielding successful cytogenetic culture were included in the study. Mean age at diagnosis was 5.6 ± 2.9 years and male to female ratio was 2.4:1. Analytical immunocytometry revealed 58 (93.5%) as B-ALL while 4 (6.55%) were T-ALL. Hyperdiploidy was detected in 19 (30.6%) and t (9:22) (q34:31) in 1 (1.6%). In all other patients no cytogenetic abnormality was detected. Out of 62 patients, Overall complete haematological remission (CHR) was achieved in 47 (75.8%). Out of 19, patients with hyperdiploidy 18 (94.7%) achieved CHR, as compared to other group without hyperdiploidy in which 29 (67.4%) achieved CHR. The difference was statistically significant (p-value 0.021).

Conclusion: Remission rate was 94.7% in patients of childhood ALL with hyperdiploidy. Patients with hyperdiploidy achieve higher CHR rate as compared to patients without hyperdiploidy.