Blood cancer does not accelerate cognitive decline among older adults
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Key takeaways:
- Cognitive decline appeared similar between older adults with or without blood cancer.
- Future studies should explore the impact of different diagnoses and treatment types.
Older adults diagnosed with a blood cancer exhibited similar rates of cognitive decline as cancer-free controls, according to study results.
This outcome remained consistent before, during and after diagnosis once investigators accounted for competing risks of death.
“Contrary to our hypothesis, the rate of cognitive decline [among] older adults after hematologic malignant neoplasm diagnosis was not faster compared with normal aging,” Li-Wen Huang, MD, assistant professor in hematology/oncology at UCSF Helen Diller Family Comprehensive Cancer Center and staff physician at San Francisco Veterans Affairs Medical Center, and colleagues wrote.
Treatment advances have improved survival for people diagnosed with blood cancer; however, limited data exist regarding cancer-related cognitive impairment among long-term survivors.
Huang and colleagues conducted a population-based cohort study to model cognitive trajectories and rates of cognitive decline among older adults before and after hematologic malignant neoplasm diagnosis.
The analysis included 668 adults (mean age, 76.8 years; 51.3% men; 87.6% white) who participated in the Health and Retirement Study. All individuals received a blood cancer diagnosis between 1998 and 2016, and about one in seven (14.4%) received chemotherapy.
The analysis included a matched cohort of 1,994 cancer-free individuals (mean age, 76.5 years; 51.2% men, 86.6% white).
Cognitive function assessed by the Langa-Weit cognitive summary score from 1992 to 2020 served as a main outcome. Researchers incorporated sociodemographic and health-related variables relevant to cognition into propensity scores.
The rate of cognitive decline between the hematologic malignancy and cancer-free cohorts appeared similar prior to and in the 2 years around the time of diagnosis.
At 1 year after diagnosis and beyond, individuals in the hematologic malignancy cohort experienced a slower cognitive decline than those in the control group (–0.18 vs. –0.24; P = .02). However, once investigators accounted for competing risk for death, the difference between the hematologic malignancy and control cohorts no longer reached statistical significance.
“The counterintuitive finding of slower cognitive decline [among] cancer survivors compared with participants without cancer may support the proposed inverse relationship between cancer and Alzheimer’s disease, where factors related to carcinogenesis may be neuroprotective,” Huang and colleagues wrote. “Another possible explanation is posttraumatic growth among cancer survivors, which posits that cancer survivors may be incentivized to adopt lifestyle changes beneficial to cognitive functioning. Alternatively, this paradoxical inverse relationship may be due to methodological biases, such as competing risks, survival bias or handling of potential confounders.”
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Huang LW, et al. JAMA Netw Open. 2024;doi:10.1001/jamanetworkopen.2024.31057.
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