Background: Over the years, survival with chemotherapy has improved in older patients with acute myeloid leukemia (AML), but data remains limited for those aged 75 and above due to their consistent underrepresentation in clinical trials. These patients are more likely to receive supportive care only, as reflected by the median age of 80.4 years among AML patients who do not receive chemotherapy. This study aims to evaluate survival outcomes and the potential benefit of chemotherapy in patients aged 75 years and older with AML. Additionally, it seeks to examine the influence of socioeconomic and demographic factors on the likelihood of receiving chemotherapy in this advanced-age population.

Methods: We performed a retrospective cohort study using the Surveillance, Epidemiology and End Results Plus (SEER Plus) data, with 17 Registries in the United States from 2000 to 2022 reporting on patients diagnosed with AML who were 65 years or older. We focused our analysis on patients aged 75 years or older (advanced age) to better understand outcomes in this population, while comparing them to the elderly patients aged 65-74. The primary outcome was overall survival (OS), defined as time from diagnosis to death due to cancer. One-year OS was estimated using Cox proportional hazards modeling combined with baseline Kaplan-Meier survival probabilities. The secondary outcomes were median survival, rate of chemotherapy utilization and the association of demographic, socioeconomic and geographic factors (age, race, ethnicity, median household income, geographic location, marital status) with chemotherapy receipt.

Results: A total of 43,054 patients with AML 65 years or older were identified between 2000–2022 (with 56.27% patients being males). The median age at diagnosis was 77 years (IQR 12) and 25,366 (58.9%) were 75 and older.

A total of 13,032 of 17,688 patients (73.6%) in elderly population (65–74 years) received chemotherapy. There was a sharp decline in chemotherapy utilization with advancing age: 58.9% in 75–79 years age 44.1% in 80–84 age, and 32.3% in 85–89 years age, and only 19.9% among patients aged ≥90 received chemotherapy (p < 0.001 for trend).

Based on pooled data from patients aged 65–74, the estimated 1-year overall survival was approximately 43%, whereas it was about 29% for those aged 75 and older. On further stratification by age in patients 75 years and older, the estimated 1 year-OS in patients who received chemotherapy vs. those who did not was 39% vs. 20% in patients aged 75–79, 31% vs. 16% in patients aged 80–84, 28% vs. 11% for patients aged 85-90, and 24% vs 10% for 90 and older, demonstrating a survival benefit with chemotherapy across all age strata (p-value <0.01).

Likewise, median survival in patients receiving chemotherapy was longer despite increasing age: 5 months vs. 1 months in those aged 75–79, 3 months vs. 1 month in those aged 80–84, and 2 months vs. 0 months in those aged ≥85. In adjusted Cox regression models, chemotherapy was associated with a reduced risk of 1-year mortality versus those who did not receive chemotherapy (HR 0.55, 95% CI 0.54–0.57; p < 0.001).

Analyzing across socioeconomic, demographic, and geographical factors: male patients as compared to females (59.1% vs. 53.7%, p<0.001), married rather than unmarried individuals (63.6% vs. 50.1%, p < 0.001), patients with higher median household income (59.9%] in ≥$100k vs. 54.3% in <$65k, p < 0.001) and those living in urban areas instead of rural (87.4% vs 12.6%) were more likely to receive chemotherapy. Small but statistically significant differences were observed in chemotherapy receipt based on race/ethnicity; Non-Hispanic Asian/Pacific had the highest treatment rate (60.6%) and the lowest rate was among Non-Hispanic Other (56.2%).

Conclusion: This study indicates that despite worse outcomes with advancing age, chemotherapy had a survival benefit across all age groups of patients with AML, including the advanced age population. It also shows that a large percentage of advanced age AML patients do not receive treatment. Patients' gender, race/ethnicity, household income, geographic location (urban vs rural) and marital status also influenced chemotherapy administration. These results suggest a potential gap in treatment for the very elderly AML population and should be confirmed with inclusion of this population in prospective studies.

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2025
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