Outcomes of Acute Myeloid Leukemia (AML) in Adolescents and Young Adults (AYAs) Compared to Adults in a Referral Center from Lower Myanmar

Abstract

Introduction Acute myeloid leukemia (AML) is the second most common form of haematological malignancies with high prevalence among all age groups in Myanmar. However, there are very limited data particularly related to AML in adolescents and young adults (AYAs). To fill the gap in AML data from resource-constraint countries and to compare the treatment outcomes of AYAs (15-39 years) with adults (40 years and above), a hospital-based, prospective study was conducted between January 2019 to October 2021, on the cases of AML treated at the North Okkalapa General and Teaching Hospital, one of three referral centers of Myanmar. Methods All cases of AML other than acute promyelocytic leukemia (APL) received two courses of induction containing daunorubicin and cytarabine followed by three courses of consolidation with high dose cytarabine. Treatment of APL included differentiation agents (all-trans-retinoeic acid and arsenic trioxide) based induction with addition of daunorubicin and cytarabine in high-risk cases until remission followed by chemotherapy free consolidation and maintenance up to two years. Patients were followed up for a minimum of one year and overall survival (OS) was calculated using the Kaplan-Meier method. Results A total of 140 including 81 (57.9%) AYAs and 59 (42.1%) adults with newly diagnosed de-novo AML were treated during 34-months period. Median age of AYA AML was 22 years (range-13-39 years) whereas that of adult AML was 54 years (range-40-76 years). There was no gender difference (49.2% versus 50.7%, for male and female). Among AML subtypes, M4 was the commonest subtype (28.5%) and APL, M3 (22.8%) was the second most prevalent AML followed by M2 (18.5%) and M5 (10.7%) subtypes. Cytogenetic data was available in 37 of 108 (34.2 %) non-APL cases with 16.2 %, 67.6% and 16.2 % respectively had good, intermediate, and high-risk cytogenetics. Of 108 non-APL including 61 (56.5%) AYAs and 47 (43.5%) adults, 46 (42.6%) died within one week or during induction and remaining 62 (57.4%) achieved remission at the end of induction. Among 32 APL (20 AYAs and 12 adults), mortality rate was 21.9% due to early death (12.5%) and induction death (9.4%) with only 78% achieved remission after induction. There was no statistically significant difference between the remission rates of AYAs and adults, in both APL (75.0% versus 83.3%, respectively, p=0.68) and non-APL groups (60.65% versus 53.2% respectively, p=0.43). During follow-up, 29 (20.7 %) were lost to follow-up while 6 non-APL AML (5 AYAs and 1 adult, 5.6%) relapsed within one year with 18 of 32 APL (56.3%) and 32 of 108 non-APL AML (29.6%) remained alive at one year. Two-year cumulative survival for AYAs compared to adults was 47% vs 42% respectively for non-APL AML (p=0.42) and 74% vs 83% for APL (p=0.608) with no statistically significant difference between two age groups. Conclusion In this resource limited setting, although having higher proportion of younger population and better prognostic types like APL, remission rate and survival was still low due to higher number of early and induction deaths which could be improved by early diagnosis and better supportive care.