Background:

Acute Promyelocytic Leukemia (APL) is a relatively uncommon and highly aggressive variant of Acute Myeloid Leukemia, also known as AML-M3. Characterized by the classic translocation t(15;17) and hence retinoic acid receptor (RAR) disruption, APL leads to accumulation of numerous immature blasts in the bone marrow. APL is notorious for causing distinctive and fatal coagulopathy due to the presence of Auer Rods. Pancytopenias with associated sequelae are frequently present. With the advent of all-trans retinoic acid (ATRA), APL has transformed from highly lethal disease to a curable neoplasm with a remission rate of over 90%. ATRA in combination with anthracycline-based chemotherapy is widely used. Newer trails with ATRA/ATO (arsenic trioxide) combination have also shown promising results. We aim to determine survival outcomes for APL based on various demographic factors.

Method:

We extracted 5403 cases of acute promyelocytic leukemia diagnosed after the age of 18 years, using the ICD Code 9866/3, from Surveillance, Epidemiology and End Result database Research Plus Data, 17 Registries, Nov 2023 Sub (2000-2021). Data was stratified based on age, gender, race, median household income inflation adjusted to 2022 and chemotherapy-based treatment regimen. Results were compared using Log-Rank test (GraphPad Prism).

Results:

Of the reported cases, APL was equally distributed among males and females. The median age of diagnosis was 51 years. Most of the cases were reported in Caucasians (57.34%), followed by Hispanics (22.75%), Blacks (10.6%), Asian/Pacific Islanders (8.4%), Alaskan/Native Americans (0.54%) and non-Hispanics of unknown race (0.4%). The Median of survival (MoS) calculated for females was 240 and males was 219 (p 0.0045). Survival based on age showed drastic decline as the age advanced (p <0.0001). Survival obtained for race was undefined for Asian/Pacific Islanders and Hispanics likely for insignificant numbers of death events, while 203 months for White (p <0.0001). Analysis based on chemotherapy showed statistically significant improvement in survival (p <0.0001). Comparison of the curves with reference to median household income revealed higher MoS with increasing income bracket (p 0.0183).

Conclusion:

Acute Promyelocytic Leukemia is a rare and belligerent subtype of AML. Distribution is gender unbiased, but frequently affects Caucasians and Hispanics. Female gender, younger age, Asian/Pacific Islander/Hispanic race, chemotherapy and higher income bracket (>100K) are associated with improved outcomes. The rarity of this neoplasm requires more research and analysis to better understand its nature.

Disclosures

No relevant conflicts of interest to declare.

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2024
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