Clinical profile and treatment outcomes in paediatric and adult acute promyelocytic leukemia: experience from a tertiary care centre in Northern India.

Acute promyelocytic leukemia (APL) is a distinct and highly curable subtype of acute myeloid leukemia. However, early mortality due to hemorrhage, differentiation syndrome (DS), and infections remains a significant challenge, particularly in resource-limited settings. There is a paucity of real-world data from India, where delayed diagnosis and high infection rates may impact outcomes. This retrospective cohort study included APL patients diagnosed at SGPGIMS, Lucknow, between July 2014 and June 2024. Diagnosis was confirmed via morphology, flow cytometry, and RT-PCR. Patients received risk-adapted induction therapy with ATRA and ATO ± anthracycline. Kaplan-Meier and multivariate Cox regression analyses were performed. Of 102 patients (median age 33 years; 17.6% pediatric), 47% were high-risk. Fever and mucocutaneous bleeding were common presentations; 18.6% had life-threatening hemorrhages, mainly intracranial. Median diagnosis delay was 18 days. DS occurred in 56% of adults and 33% of pediatric patients. Pseudotumor cerebri and hepatotoxicity occurred in 7.8% and 37.6%, respectively. CR was achieved in 76.4% (87% low-risk vs. 64.6% high-risk). Induction mortality (24.5%) was mainly due to bleeding and infections. At a median follow-up of 28 months, 2-year OS was 75.9% (low-risk: 90.4%; high-risk: 65.9%), and DFS was 89.6% (low risk: 91.8% ; high risk:78.6%). Infection during induction and poor ECOG performance status independently predicted induction mortality. Early mortality in APL remains high due to delayed diagnosis, infections and bleeding complications. Region-specific challenges necessitate timely intervention and tailored supportive care to improve outcomes in Indian APL patients, especially in pediatric and high-risk groups.