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Some sufferers of mesothelioma report having impaired cognitive functioning, described as similar to “dementia.” This cognitive impairment manifests itself in symptoms like brain fog, short-term memory loss, sudden fatigue, an inability to concentrate, difficulty multitasking, and other, similar experiences.
However, neither mesothelioma nor asbestos exposure are known to lead directly to cognitive disabilities that exhibit dementia, such as Alzheimer’s disease[1]. Instead, there may be a correlation between mesothelioma risk and risk of cognitive impairments because both conditions tend to develop in older adults[2],[3]. Additionally, the treatment of mesothelioma through surgery or chemotherapy may lead to temporary impairments to cognitive functioning that can exhibit similarities to dementia.
“Dementia” describes a range of symptoms that all relate to diminished mental faculties and cognitive decline. Dementia is, itself, not a condition nor a diagnosis[4]. Instead, the term is used to describe conditions that directly result in cognitive decline and impaired functioning. Such conditions include: Alzheimer’s disease, Parkinson’s disease, vascular dementia, Lewy body dementia, frontotemporal dementia, or a “mixed dementia” diagnosis that describes multiple co-occurring conditions[5].
Pleural mesothelioma, on the other hand, is a rare form of cancer affecting the pleural lining surrounding the lungs. Most patients who develop mesothelioma have a history of asbestos exposure, and there is a documented link between exposure and later development of the rare form of cancer[6].
Mesothelioma’s symptoms do not include cognitive impairment, but cancer is known to cause changes in the body’s metabolism that lead to chronic fatigue[7]. The tumors on the pleural lining could also metastasize to the brain, causing tissue damage that leads to cognitive decline, but such metastases are rare, only present in about 3% of mesothelioma cases[8].
Individuals who receive a mesothelioma diagnosis and begin treating their disease may encounter complications that lead to temporary side effects that are superficially similar to dementia. Major thoracic surgery, for instance, has an association with declined mental functioning as the patient recovers[9]. This association has strong links to anesthesia drugs used before surgery as well as the general strain surgery places upon the body’s metabolic functioning.
Furthermore, chemotherapy treatment has a strong association with temporary cognitive decline — a condition commonly described as “chemo brain”. Common symptoms associated with chemo brain include: confusion, difficulty recalling words or names, short attention spans, difficulty completing tasks, fatigue, and a general feeling of mental “fogginess”[10].
Chemo brain is an extremely common side effect of treatment. “Virtually all cancer survivors experience short-term memory loss and difficulty concentrating during and shortly after treatment,” writes Dr. Mark Noble of the University of Rochester Medical Center[11]. Noble cites research that shows more than 82% of breast cancer survivors report at least some diminished cognitive functioning.
While chemo brain is supposed to be a temporary condition that diminishes over time or at least remains stable[12], conditions related to dementia worsen over time, setting the two apart. There has also been no firm link between chemotherapy and permanent cognitive decline, exemplified by studies that make conclusions like: “Chemotherapy does not appear to cause the same biochemical changes in the brain that are found in Alzheimer’s disease.”[13]
Therefore, the scientific consensus is that any true forms of dementia that develop or emerge after a mesothelioma diagnosis may be related to treatment, aging, or unrelated risk factors.
Even still, limited evidence does exist directly linking asbestos exposure or chemotherapy treatment to permanent cognitive decline[14],[15]. Further research is needed before the evidence of such a direct causation could be proven.
[1] https://www.alzheimer-europe.org/News/EU-developments/Thursday-01-August-2013-Asbestos-is-not-a-root-cause-of-Alzheimer-s-disease
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4406225/
[3] https://www.alzheimers.org.uk/sites/default/files/pdf/factsheet_risk_factors_for_dementia.pdf
[4] https://www.medicalnewstoday.com/articles/142214.php
[5] https://www.mayoclinic.org/diseases-conditions/dementia/symptoms-causes/syc-20352013
[6] https://www.mayoclinic.org/diseases-conditions/mesothelioma/symptoms-causes/syc-20375022
[7] https://www.mayoclinic.org/diseases-conditions/cancer/in-depth/cancer-fatigue/art-20047709
[8] http://ascopubs.org/doi/abs/10.1200/JCO.2017.35.15_suppl.8556
[9] https://www.mesotheliomacircle.org/study-could-help-mesothelioma-cognitive-impairment/
[10] https://www.mayoclinic.org/diseases-conditions/chemo-brain/symptoms-causes/syc-20351060
[11] https://www.urmc.rochester.edu/news/story/1963/researchers-detail-chemotherapys-damage-to-the-brain.aspx
[12] https://www.dana-farber.org/health-library/articles/tips-for-managing-chemobrain/
[13] https://consults.blogs.nytimes.com/2009/08/17/a-writer-with-chemo-brain-and-attention-deficit-disorder/
[14] https://www.alzdiscovery.org/cognitive-vitality/blog/chemo-brain-and-alzheimers-risk
[15] https://www.ncbi.nlm.nih.gov/pubmed/3957626
