People with cancer may experience difficulty with thinking ability, including memory loss, distractibility, difficulty in performing multiple tasks (multitasking), and trouble with arithmetic and language skills. People with cancer generally have fairly mild, limited cognitive problems, that tend to respond very well to focused rehabilitation efforts. Several treatment options offer hope and assistance for this concerning symptom that often accompanies the cancer experience.

Key Points/Overview

Forgetting an important date or the name of a long-time associate, being unable to read an entire newspaper article in one sitting, suddenly finding it impossible to prepare family dinners that were once second nature--many people with cancer are surprised to discover that they have cognitive problems surrounding the cancer experience. Cognitive functioning is the information-handling aspect of behavior and encompasses the brain's attaining, processing, storage and retrieval of information. Many people with cancer experience difficulty with cognitive function, including memory loss, distractibility, difficulty in performing multiple tasks (multitasking), and trouble with arithmetic and language skills. Concerns relating to cognitive functioning may range in severity, intensity and duration.

The causes of cognitive problems are many, including the direct effects of cancer within the central nervous system, indirect effects of certain cancers, or effects of cancer treatments on the brain. Cognitive impairments may be subtle and go unnoticed, but they may also represent a devastating collection of symptoms for people with cancer. Cognitive impairment is a frequent finding in people with cancer with a prevalence of up to 85% in the far advanced stages of illness. 2

For people with cancer the most common types of memory impairment include problems with short-term memory , the storage of information from seconds to hours to days. Long-term memory is not often affected in people with cancer. The cognitive processes most affected include attention, learning and memory, and psychomotor efficiency.

Alterations in cognitive function are not necessarily related to a person's age. Cognitive impairments occur similarly in both children and adults with cancers. The repercussions for children may be long-term in nature, including difficulty with academic performance (particularly arithmetic), career pursuits, and quality of life.

Risk Factors for Cognitive Dysfunction in Cancer

You may be at higher risk for cognitive difficulties if you have the following:
Anemia, Hypoxia (Deficiency of oxygen)
Radiation Therapy
Hormone Therapy
Emotional Disturbance
Central Nervous System Cancers
Kidney Failure
Liver Failure
Fluid & Electrolyte Imbalance
Certain medications
Nutritional Deficiency
Cognitive Dysfunction
Cognitive dysfunction affects your:
Attention Span
Organizational Ability
Arithmetic Skills
Language Skills
Reduced Quality of Life
Cognitive dysfunction can impact upon your quality of life by affecting your:
Activities of Daily Living
Interpersonal Relationships
Future Education

Causes of Cognitive Dysfunction in Cancer

Cancer Treatments
Advances in the success of treating cancer have been achieved through the combined use of surgery, radiation, cytotoxic drugs (ie. chemotherapy) and immunotherapy. Many cancer treatments are not specific, that is, they affect more parts of your body than just where the tumor is located, and therefore place organs and tissues at risk. The central nervous system, including the brain, is particularly vulnerable to many cancer treatments. Studies estimate that 18% of persons receiving standard dose chemotherapy regimens experience cognitive dysfunction and those receiving high-dose adjuvant (agents used in combination that hasten or enhance the action of the primary agent) therapies have a higher incidence rate. 15 More than 50% of persons receiving immunotherapy treatment (cytokines such as interferon, interleukin) experience memory, motor, executive functions (functions which allow self-control over our behavior and emotions) and mood alterations. 5 Among the treatments for hormonally sensitive cancer (breast, ovarian, testicular, prostate) are surgical or medication manipulation that reduce the amount of circulating sex hormones; there is a high occurrence; there is a cognitive dysfunction and these deficits appear to be directly related to the reduction in sex hormones. 7,16

Additionally, many medications used to manage medical complications may cause side effects of cognitive impairment (immunosuppressive agents used in bone marrow transplant, antibiotics, steroids, drugs used to manage pain, nausea/vomiting, and other cancer-related symptoms).

Infection and Anemia
Infections and low red blood cell counts (anemia) are common in people with cancer and may result in cognitive dysfunction. People undergoing active treatment are particularly susceptible to infections and anemia.

Metabolic Problems
Some cancers themselves produce hormones or neurochemicals that alter the brain's function (small cell lung cancer, acute leukemia are two examples). Also, decreased production of thyroid hormones, produced by the thyroid gland in the neck, may reduce acuity of thinking and may be associated with low mood states. Dysfunction of the liver or kidneys may cloud mental functioning due to the accumulation of toxins within the blood that are normally excreted.

Nutritional Deficiency
Deficiencies in iron, vitamin B and folic acid may cause a decline in attention, perceptual-motor speed, memory, and verbal fluency.

Direct Causes of Cognitive Dysfunction
Tumors located in the central nervous system cause a predictable and progressive decline in mental functioning. In addition, the spread of cancer to the central nervous system can lead to cognitive dysfunction.

Addressing cognitive impairment as a symptom of cancer is important in restoring optimal quality living.

Recognizing Cognitive Dysfunction in Cancer

A number of cognitive function scales or tools have been developed to help healthcare providers recognize changes in cognitive functioning. Examples of screening tools your healthcare provider may use include:

Folstein Mini Mental Status Examination

Task Instructions Scoring
Date Orientation "Tell me the date?" Ask for omitted items. One point each for year, season, date, day of week, and month 5
Place Orientation "Where are you?" Ask for omitted items. One point each for state, county, town, building, and floor or room 5
Register 3 Objects Name three objects slowly and clearly. Ask the patient to repeat them. One point for each item correctly repeated 3
Serial Sevens Ask the patient to count backwards from 100 by 7. Stop after five answers. (Or ask them to spell "world" backwards.) One point for each correct answer (or letter) 5
Recall 3 Objects Ask the patient to recall the objects mentioned above. One point for each item correctly remembered 3
Naming Point to your watch and ask the patient "what is this?" Repeat with a pencil. One point for each correct answer 2
Repeating a Phrase Ask the patient to say "no ifs, ands, or buts." One point if successful on first try 1
Verbal Commands Give the patient a plain piece of paper and say "Take this paper in your right hand, fold it in half, and put it on the floor." One point for each correct action 3
Written Commands Show the patient a piece of paper with "CLOSE YOUR EYES" printed on it. One point if the patient's eyes close 1
Writing Ask the patient to write a sentence. One point if sentence has a subject, a verb, and makes sense 1
Drawing Ask the patient to copy a pair of intersecting pentagons onto a piece of paper.

One point if the figure has ten corners and two intersecting lines 1
Scoring A score of 24 or above is considered normal. 30

Note. From “Mini-mental state: A practical method for grading the state of patients for the clinician,” by M. Folstein, S. Folstein and P. McHugh, 1975, Journal of Psychiatric Research, p. 189-198.

Short Portable Mental Status Questionnaire
  1. What are the date, month, and year?
  2. What is the day of the week?
  3. What is the name of this place?
  4. What is your phone number?
  5. How old are you?
  6. When were you born?
  7. Who is the current president?
  8. Who was the president before him?
  9. What was your mother's maiden name?
  10. Can you count backward from 20 by 3's?
0-2 errors: normal mental functioning
3-4 errors: mild cognitive impairment
5-7 errors: moderate cognitive impairment
8 or more errors: severe cognitive impairment

*One more error is allowed in the scoring if a patient has had a grade school education or less. *One less error is allowed if the patient has had education beyond the high school level.

Consequences of Cognitive Dysfunction in Cancer

The consequences of cognitive impairment for people with cancer include interfering with the ability to make treatment related decisions, complete normal activities of daily living, and maintaining professional and social roles.