Clinical Characteristics and Treatment Complications of Acute Promyelocytic Leukemia in Afro-Caribbean Patients: Insights from a New York City Public Hospital
Authors: Thida Aye Mon , Chen Lan , Gonsky Jason , Chiu Edwin 
Published: December 2024

Background:
The early mortality rate in real-world practices for acute promyelocytic leukemia (APL) remains high in the United States despite advances in treatment and supportive care. Challenges such as early deaths during induction therapy and the need to optimize treatment for high-risk patients contribute to this issue. While African American patients have a reported lower incidence of APL compared to other ethnoracial groups, data on APL disease and treatment outcomes in Afro-Caribbean patients is not well-studied. Our study aimed to investigate APL in Afro-Caribbean patients using our institutional cohort's experience with disease presentation and treatment outcomes.
Method:
We conducted a retrospective analysis of Afro-Caribbean patients diagnosed and treated for APL at New York City Health and Hospitals Kings County between 2012 and 2022. Medical records were reviewed for patient demographics, clinical course, and treatment outcomes. A baseline white blood cell count was used to assign risk status and assess treatment concordance with National Comprehensive Cancer Network guidelines. Data was tabulated through summary analysis and descriptive statistics.
Results:
We identified 8 patients with APL, with a median presentation age of 65.5 years (range, 23-73 years), and 4 were female. Of 8 patients, 7 (87.5%) were obese, and 2 (25%) had previously been treated with chemotherapy for different cancers. Five of the 8 patients (63%) did not have regular pre-hospitalization medical care. Patients presented with disseminated intravascular coagulation (5 patients), clinical stroke (2 patients), and sepsis from pneumonia (1 patient). Peripheral blood smear morphology revealed hypergranular-APL (4 patients) and hypogranular-APL (4 patients). Of 4 hypogranular-APL patients, 3 were high-risk. The median time from APL suspicion to all-trans retinoic acid (ATRA) induction treatment was 2 hours. All patients were started on induction ATRA-based treatment and developed the following complications: 4 developed differentiation syndrome (median time, 3.5 days), 2 with fungemia, and 2 with thrombohemorrhagic events. Three patients died during induction treatment. Five patients who tolerated induction treatment had subsequent bone marrow biopsy and aspirate on day 28. Of 5 surviving patients, 1 had complete remission, and 3 had complete remission with incomplete count recovery, with a median time of 48.4 days (range, 29-69 days). One patient developed septic shock and died during consolidation therapy. Four patients who successfully completed consolidation therapy had a median survival time from diagnosis to censoring of 70.5 months (range, 32-142 months). None had relapse nor required hematopoietic stem cell transplantation.
Conclusion:
Healthcare disparities are well known in African American patients in acute myeloid leukemia treatment and outcomes. However, APL disease and treatment characteristics of Afro-Caribbean patients are less well-known. In the largest retrospective study of real-world APL from the National Cancer Database (2022), it is noted that early mortality at 1 month in patients over age 60 years is 21%. In our series of 8 patients, 6 were over age 60 years (75%). Among these 6 patients, 4 received no pre-hospital medical care, and 2 presented with hypogranular-variant and high-risk APL and died during treatment, translating to a 33% case fatality rate. A lack of pre-hospitalization medical care may have obscured medical comorbidities contributing to the adverse outcomes of these older adults with APL despite optimal APL treatment. Our cohort of 8 Afro-Caribbean patients with APL presented at a median age of 65.5 years (national median age of 40 years), 3 presented with high-risk disease (38%), and 5 patients received no prior primary care (63%). Further research is necessary to determine the broader applicability of these findings to the larger patient populations with APL.