Sandbox: Post-chemotherapy cognitive impairment
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Synonyms and keywords: Chemotherapy-induced cognitive dysfunction; Chemo brain; Chemo fog; Chemobrain; PCCI
Overview
Post-chemotherapy cognitive impairment (also known as chemotherapy-induced cognitive dysfunction) is defined as the cognitive impairment that can result from chemotherapy treatment. Post-chemotherapy cognitive impairment was first discovered and described in 1980.[1] Post-chemotherapy cognitive impairment is characterized by changes in memory, fluency, and other cognitive abilities that impeded their ability to function as they had pre-chemotherapy. Approximately 20-30% of patients that undergo chemotherapy experience some level of post-chemotherapy cognitive impairment. The exact pathogenesis of post-chemotherapy cognitive impairment is not fully understood.[1] However, the underlying mechanisms of the disease are believed to be caused by direct neurotoxicity. Genes involved the development of post-chemotherapy cognitive impairment, include: COMT nucleotide polymorphism, Apolipoprotein E gene, and BDNF gene mutations. Post-chemotherapy cognitive impairment is more commonly observed among middle aged and elderly patients. The median age at diagnosis ranges between 40-70 years old. There are no specific imaging findings associated with post-chemotherapy cognitive impairment. However, in some cases MRI may detect accurate measurement of therapy-induced changes in gray and white matter volumes. Recent studies suggest further investigation on the underlying mechanisms of cognitive impairment.[2]
Historical Perspective
- Post-chemotherapy cognitive impairment was first discovered and described in 1980.[1]
Classification
- There is no classification system for post-chemotherapy cognitive impairment.[1]
Pathophysiology
- The pathogenesis of post-chemotherapy cognitive impairment is not fully understood.[1]
- However, the underlying pathophysiology is believed to be caused by direct neurotoxicity.
- Genes involved the development of post-chemotherapy cognitive impairment, include:[1]
- COMT nucleotide polymorphism
- Apolipoprotein E
- BDNF gene
- On gross pathology, characteristic findings of post-chemotherapy cognitive impairment, include:[1]
- No remarkable findings
- On microscopic histopathological analysis, characteristic findings of post-chemotherapy cognitive impairment, may include:
- Smaller tumor size
- Reduced cellularity
- Extensive cytoplasmic vacuolization causing tumor cells to resemble histiocytes
- Tumor necrosis
- Atrophy and marked nuclear atypia
Causes
- Common causes of post-chemotherapy cognitive impairment, include:[3]
Differentiating Post-Chemotherapy Cognitive Impairment from Other Diseases
- Post-chemotherapy cognitive impairment must be differentiated from other diseases that cause cognitive impairment (such as, lack of attention, orientation to time and space), such as:[1]
Epidemiology and Demographics
- Post-chemotherapy cognitive impairment is rare.
- Approximately 20-30% of patients that undergo chemotherapy experience some level of post-chemotherapy cognitive impairment.
- The prevalence of post-chemotherapy cognitive impairment remains unknown.[1]
Age
- Post-chemotherapy cognitive impairment is more commonly observed among patients aged 40-70 years old.
- Post-chemotherapy cognitive impairment is more commonly observed among middle aged adults and elderly patients.
Gender
- Females are slightly more commonly affected with post-chemotherapy cognitive impairment than males.[2]
Race
- There is no racial predilection for post-chemotherapy cognitive impairment.[2]
Risk Factors
- The most common risk factor in the development of post-chemotherapy cognitive impairment are number of cycles of chemotherapy.[3]
Natural History, Complications and Prognosis
- The majority of patients with post-chemotherapy cognitive impairment are initially symptomatic.[1]
- Early clinical features, include:
- Lack of attention
- Memory loss
- Problems to recall
- Lack of orientation
- If left untreated, patients with post-chemotherapy cognitive impairment may progress to develop severe cognitive impairment.
- Common complications of post-chemotherapy cognitive impairment, include:[3]
- Decreased executive function
- Cerebrovascular disorders
- Focal neurological deficits
- Prognosis will generally good, and symptoms of post-chemotherapy cognitive impairment typically disappear in about four years.
Diagnosis
Symptoms
- Post-chemotherapy cognitive impairment is usually symptomatic at diagnosis
- Symptoms of post-chemotherapy cognitive impairment may include the following:[1]
- Memory loss
- Lack of attention
- Difficult language fluency
- Poor calculation and recall
- Loss of appetite
- Irritability or constant mood swings
- Hopelessness
- A directed history should be obtained to ascertain:
- Aggravating factors, such as:
Physical Examination
- Patients with post-chemotherapy cognitive impairment usually appear malnourished and pale.
- Physical examination shows no remarkable findings for patients with post-chemotherapy cognitive impairment.[3]
Laboratory Findings
- There are no specific laboratory findings associated with post-chemotherapy cognitive impairment.[1]
- In some cases, elevated levels of apolipoprotein (APOE) allele may be seen in patients with post-chemotherapy cognitive impairment
Imaging Findings
- There are no imaging findings associated with post-chemotherapy cognitive impairment.
- In some cases, MRI may detect accurate measurement of therapy-induced changes in gray and white matter volumes.
Treatment
Medical Therapy
- There is no treatment for post-chemotherapy cognitive impairment; the mainstay of therapy is supportive care.
- Common medical therapies for the treatment of post-chemotherapy cognitive impairment, include:[3]
Surgery
- Surgery is not recommended for patients with post-chemotherapy cognitive impairment.[1]
Prevention
- There are no primary preventive measures available for post-chemotherapy cognitive impairment.[1]
- Once diagnosed and successfully treated, patients with post-chemotherapy cognitive impairment are followed-up every visit.
- Follow-up testing includes cognitive function assessments (such as, mini–mental state examination)
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 Janelsins MC, Kohli S, Mohile SG, Usuki K, Ahles TA, Morrow GR (2011). "An update on cancer- and chemotherapy-related cognitive dysfunction: current status". Semin. Oncol. 38 (3): 431–8. doi:10.1053/j.seminoncol.2011.03.014. PMC 3120018. PMID 21600374.
- ↑ 2.0 2.1 2.2 Post-chemotherapy cognitive impairment. Wikipedia. https://en.wikipedia.org/wiki/Post-chemotherapy_cognitive_impairment Accessed on May 18, 2016
- ↑ 3.0 3.1 3.2 3.3 3.4 Aleah J. McHenry, MSN, RN. Management of Chemotherapy Induced Cognitive Impairment. http://www.oncolink.org/resources/article.cfm?id=1057 Accesed on May 18, 2016