Impact of Molecular and Cytogenetic Responses on Long-Term Outcomes in Children and Adolescents With Chronic Myeloid Leukemia: A Retrospective Study From India.

Introduction Chronic myelogenous leukemia (CML) in pediatric and adolescent populations is relatively rare. The present study provides an integrated approach to evaluate the impact of molecular and cytogenetic response on long-term outcomes in these populations by incorporating demographic factors and hematological parameters, and to explore their clinical relevance in resource-limited settings. Material and methods A retrospective analysis was conducted on patients <18 years with newly diagnosed CML from January 2014 to December 2023 at the Gujarat Cancer and Research Institute in India. Data were retrieved from the hospital database, including demographics, clinical details, hematological parameters, CML phase at diagnosis, and cytogenetic and molecular studies. Of 73 diagnosed patients, eighteen were not subjected to molecular, cytogenetic, and complete hematological response (CHR) analysis due to factors such as irregular follow-up, testing constraints, and financial or logistic barriers. Results Of the 73 patients, seventeen (23%) were below 10 years of age, and 56 (77%) were above 10 years at the time of diagnosis. The male-to-female ratio was 1.8:1. Seventy (96%) of the 73 patients were initially diagnosed with CML in the chronic phase, and three patients (4%) were diagnosed with CML in blast crisis. Response evaluation was conducted on 55 patients. Of these, CHR was observed in 41 (74%) patients at 3 months. At 12 months, forty (73%) achieved complete cytogenetic response (CCyR), and 25 (45%) achieved major molecular response (MMR). Among the 55 patients, those who achieved CCyR and MMR at 12 months had a 100% five-year survival, compared to 66.7% and 83%, respectively, in those who did not achieve a response. Patients who achieved early molecular response (EMR) had a 97.4% five-year survival. The Kaplan-Meier estimated overall survival was 91.6% at 3 years and 87.6% at 5 years. Fifty of the 55 patients (91%) were alive at long-term follow-up, with a median duration of follow-up of 62 months (range: 0-128 months). Patients aged 0-10 years and >10 years had five-year survival rates of 100% and 88%, respectively. Conclusion The achievement of molecular and cytogenetic responses has a significant impact on long-term outcomes in pediatric and adolescent patients diagnosed with CML, highlighting their role as crucial predictors in clinical practice. Patients who achieved both MMR and CCyR demonstrated 100% five-year overall survival (OS), while those with EMR showed a 97.4% five-year survival. These findings support the utility of early response monitoring to inform prognosis and guide therapy, particularly in low- and middle-income countries (LMICs). However, treatment abandonment and poor compliance remain major obstacles in LMICs. Further research with multicentric prospective trials in LMICs is essential.