Long-Term Outcome of Philadelphia Chromosome Positive Leukemia From Eastern Indian Subcontinent: An Experience in the Era of Tyrosine Kinase Inhibitor (TKI) Therapy

Abstract

Introduction: Philadelphia chromosome (Ph) marks a group of leukemia with almost all cases of chronic myeloid leukemia (CML), a subset of acute lymphoid leukemia (ALL) and rare cases of acute myeloid leukemia (AML). In the era of precision medicine, such cases are successfully managed with tyrosine kinase inhibitor (TKI) drugs. This study examined the features and long-term outcome of Ph+ve cases from a tertiary cancer care center from Eastern Indian subcontinent.

Materials and methods: Reviewing retrospective case-records registered between 2005 and 2015, cases of CML and ALL were documented under Ph+ve category; while no instance of Ph+ve AML was found.

Results: In CML cohort, adult and juvenile incidences were 95.2% and 4.8% respectively; in ALL cohort, the same was found for 66.67% and 33.33% cases. Among the CML cases, 10-year overall survival (OS) and progression-free survival (PFS) were significantly affected upon the phase of disease at time of detection. Furthermore, both OS and PFS significantly dropped whenever non-TKI-based treatment was applied prior to TKI-commencement. Long-term (10-year) sensitivity to 1st generation TKI, imatinib, was noted 88.51% and 83.33% for adult and juvenile CML cohorts, respectively. For Ph+ ALL cohort, the OS was benefitted upon combinatorial TKI and chemotherapy. However, large fractions of affected individual from CML as well as ALL cohorts were found to discontinue follow-up.

Conclusion: Together with differences in outcome on the basis of drug-use from onset, age (juvenile versus adult) and stage at diagnosis, our analyses bring forward the real-world scenario of Ph+ve leukemia managed with precision medicine.

Keywords: Acute lymphoid leukemia (ALL); BCR-ABL1; Chronic myeloid leukemia (CML); Imatinib; Survival Outcome.