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JANINE KEYSER, 48, underwent fourcycles of chemotherapy with doxoru-bicin and cyclophosphamide to treatbreast cancer. During treatment, sheexperienced increasing fatigue and haddifficulty concentrating and multitask-ing at work. Then, when she begantreatment with paclitaxel, she hadtrouble recalling names and words,and couldn’t finish even simple tasks.After her third dose of paclitaxel, Ms.Keyser’s cognitive deficits were sosevere that she had to take a leave ofabsence from work. She told friendsshe felt like she was “in a fog” thatwouldn’t lift.

During and after treatment for can-cer, many patients experience cognitiveimpairment secondary to chemothera-py. Informally known as chemo brain,this phenomenon can be profoundlydisturbing and life-altering for apatient already dealing with a cancerdiagnosis. In this article, I’ll explainwhat we know about this conditionand how you can help your patientcope with it.

Fuzzy thinkingA poorly understood but very realphenomenon, cognitive impairmentsecondary to chemotherapy can affectmemory, attention, and problem-solvingability. It was first identified in the1980s, when breast cancer patientsreported difficulties with cognitionduring and after chemotherapy. Manywere soon referring to the condition aschemo brain or chemo fog. Commonlyreported difficulties include:• poor word or name recall• difficulty staying focused• diminished ability to learn new things• difficulty managing daily activities• decreased ability to multitask.1

An estimated 20% to 30% ofpatients undergoing chemotherapy—men and women alike—experiencechemo brain. Although the brain mayrecover over time, research has shownthat various cancer treatments cancause structural brain abnormalitiesthat may persist for years. A geneticpredisposition may be a factor formany patients.2,3

Patients are typically aware of theircognitive changes but can’t emergefrom the fog. They feel frustrated andhelpless, adding to the burden of emo-tions that go with a cancer diagnosis(see Rapid recall for nurses: Tips forpatient support for ways you can helpthem deal with cognitive problems).

Because problems may be subtleand produce no outward physicalsigns, chemo brain is difficult to assess.What’s clear is that it can significantlyimpact quality of life by interferingwith a patient’s daily routines, familylife, career, and plans for the future.

No one can predict which patientswill develop cognitive impairment sec-ondary to chemotherapy, and for thosewho do, severity and duration arehighly variable. The time frame for theonset of cognitive impairment is alsounpredictable: Changes can start asearly as the first chemotherapy treat-ment, or may be cumulative and devel-op after subsequent cycles.

The duration and resolution of cog-nitive problems may be influenced by

Understanding “chemo brain”Learn how to assess your patient for cognitive impairment related to cancer

chemotherapy and help her cope with this often unanticipated condition.

By Donna L. Hafner, RN, OCN, MSN

the fog the fog

the patient’s treatment regimen, age,and other health problems. The physi-cal and emotional stress of diagnosisand treatment can exacerbate cognitiveproblems, which may worsen over thecourse of treatment and linger longbeyond its completion.

Currently, no preventative measuresare available, nor have standardizedevaluation tools or effective treatmentsbeen developed. For these reasons,chemo brain can be extremely frustrat-ing for caregivers as well as the patient.

What’s behind chemo brain?Breast cancer patients who’ve under-gone chemotherapy are the largestgroup of cancer survivors, so researchon chemo brain to date has focused onthem.4 Studies have shown a correla-tion between cognitive impairment andchemotherapy, but pinpointing causeshas been difficult because of differ-ences in study design, patient charac-teristics, comparison groups, andchemotherapy regimens.5

Although more research is needed,the following triggers have been postu-lated as possible causes.

Chemotherapy-induced toxicity.Patients getting chemotherapy drugsknown to be toxic to the central ner-vous system (central neurotoxicity)have a greater incidence of cognitiveimpairment. Some drugs, such as

cytarabine and methotrexate, causeneurotoxicity by crossing the blood-brain barrier and causing direct dam-age to neurons in the cerebral cortex.Similarly, metabolites of drugs such asifosfamide and 5-fluorouracil can alsocross the blood-brain barrier. The cere-bral cortex is responsible for highercognitive functions such as thinking,learning, problem-solving, and memory.

Patients undergoing chemotherapyshould be monitored for toxicity, butstandard assessment tools aren’t diag-nostic. Keep in mind that your patientmay be struggling with cognitiveimpairment even if physical assess-ment findings and blood tests arewithin normal limits.

Inflammatory response. Chemo-therapy drugs such as paclitaxel and

vincristine can trigger an inflammatoryresponse that indirectly affects the cen-tral nervous system. When toxic sub-stances bypass the body’s first line ofdefense (physical, mechanical, andbiochemical barriers), the inflammato-ry response is activated. During theacute inflammatory response, signalingproteins called proinflammatorycytokines are released. Circulating inthe bloodstream, these cytokines canpenetrate the blood-brain barrier, trig-gering an inflammatory response in thebrain. Research indicates that thesecytokines can disrupt neural signalingin the part of the brain responsible forshort-term memory.1

This excessive release of proinflam-matory cytokines is also associated witha syndrome of physiologic and behav-ioral signs and symptoms known as“sickness behavior.” Signs and symp-toms occur 2 to 3 days after treatmentand can include fever, fatigue, myalgia,anorexia, decreased ability to concen-trate, and behaviors consistent withenergy conservation such as sleeping.1,6

Oxidative stress. Chemotherapyagents can trigger oxidative stresswhen the body produces more unsta-ble, cell-damaging substances calledoxygen free radicals than it can neu-tralize or eliminate. The imbalanceoccurs when the body lacks enoughantioxidants, which normally protectcells by neutralizing oxygen free radi-cals. Oxygen free radicals damage DNAand other key cellular components incells throughout the body, includingthose in the central nervous system.1

Anemia. Chemotherapy can causebone marrow suppression and reducered blood cell (RBC) production,resulting in anemia. Because of theirlevel of metabolic activity, neuronshave a high oxygen demand. By reduc-ing oxygen-carrying RBCs, anemia cancompromise cerebral perfusion andimpair the patient’s ability to thinkclearly.

Hormone suppression. Many chemo-therapy drugs can suppress hormoneproduction. In a young woman, this

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Rapid recall for nurses: Tips for patient support Observe. Your observations during interactions with patients may lend impor-tant information on cognitive deficits such as word recall and memory retrieval.Ask. Inquire whether your patient has noticed any change in her ability to con-centrate or to stay focused when performing a task. Is she able to multitask?Educate. Provide information about cognitive impairment secondary tochemotherapy and give her information about coping strategies if she experi-ences this problem.Identify. Determine if other factors may be contributing to her cognitivedysfunction, such as depression, stress, anemia, insomnia, or medications.Support. Let her know that support is available to help her manage cognitivedeficits. See Resources at the end of this article.Advocate. Alert other healthcare professionals when a patient is experiencingcognitive impairment.Validate and reassure. Validation that chemo brain is a real phenomenon willhelp reassure your patient, who may think she’s “going crazy” or “losing it.”

Anemia can compromise cerebral perfusion and

impair the patient’s ability to think clearly.

can significantly decrease the body’sestrogen level and cause prematuremenopause. In addition, women withsome types of breast cancer may betreated with drugs such as tamoxifenor raloxifene to prevent conversion ofandrogen to estrogen or to block estro-gen from binding to cell receptors.Decreased estrogen levels can affectcognitive function because manyreceptors in the brain require estrogento stimulate neuronal activity.

Other factors. Medications com-monly prescribed for patients withcancer, such as steroids, antiemetics,benzodiazepines, and analgesics, canaffect the central nervous system andimpair cognitive function. Fatigue,anxiety, and depression can impair cog-nition as well. The degree to whichother factors impact cognition isunknown but likely to be significant.

Diminished quality of lifeMost patients are prepared for well-known adverse reactions to chemo-therapy treatment, such as alopecia ornausea, but few expect cognitive prob-lems. Having trouble performing dailyactivities, maintaining family roles, orperforming on the job can be frighten-ing and distressing and significantlydiminish the patient’s quality of life. Inaddition, she can’t be sure when nor-mal cognitive function will return.

Educate your patient and her familythat cognitive impairment is a potentialtreatment-related reaction to raise theirawareness and provide emotional sup-port. Encourage your patient to discussthis adverse reaction with her oncologyhealthcare team and give her tips forcoping with cognitive dysfunction.7

(See Strategies for daily living.)When you identify a patient at risk

for cognitive impairment secondary tochemotherapy, consult with her oncol-ogy healthcare team to develop a planof care and help her get support ser-vices she needs. For example, Ms.Keyser, the patient we met at thebeginning of the article, might bereferred to a neuropsychologist for

help with her cognitive functions andan oncology advance practice nurse tohelp her deal with the emotional dis-tress associated with a cancer diagnosisand adverse reactions to treatment. Asocial worker can help her with jobloss, insurance matters, and otherfinancial issues.

Emerging from the hazeFive months after completing chemo-therapy, Ms. Keyser returned to work.Over the next few months, her ability toperform her duties steadily improved.Today, 3 years after completing treat-ment for breast cancer, she has noapparent cognitive deficits.

Until research tells us more aboutthe causes and solutions, you can helppatients like Ms. Keyser understandthe risk of cognitive impairment andmanage the effects. ✧

REFERENCES

1. Myers JS, Teel C. Oncology nurses’ aware-ness of cognitive impairment secondary tochemotherapy. Clin J Oncol Nurs. 2008;12(5):725-729.

2. American Cancer Society. Chemo brain.http://www.cancer.org.

3. National Cancer Institute. Delving into pos-sible mechanisms for chemobrain. NCI CancerBulletin. 2009;6(6):8. http://www.cancer.gov/ncicancerbulletin/032409/page8.

4. Staat K, Segatore M. The phenomenon ofchemo brain. Clin J Oncol Nurs. 2005;9(6):713-721.

5. Kayl AE, Wefel JS, Meyers CA. Chemother-apy and cognition: effects, potential mecha-nisms, and management. Am J Ther. 2006;13(4):362-369.

6. Myers JS. Proinflammatory cytokines andsickness behavior: implications for depressionand cancer-related symptoms. Oncol NursForum. 2008;35(5):802-807.

7. Doctor, can we talk about chemobrain? NewYork, NY: Cancer Care, Inc.; 2007. http://www.cancercare.org/pdf/fact_sheets/fs_chemobrain_doctor_talk.pdf.

8. Combating chemobrain: keeping your mem-ory sharp. New York, NY: Cancer Care, Inc.;2008. http://www.cancercare.org/pdf/fact_sheets/fs_chemobrain_memory.pdf.

RESOURCES

American Cancer Society1-899-ACS-2345www.cancer.org

American Psychological Association 1- 800-374-2721 www.apa.org

American Psychosocial Oncology Society 1-866-276-7443 www.apos-society.org

Chemobrain Informationwww.chemobraininfo.org

National Cancer Institutewww.cancer.gov

Donna L. Hafner is an oncology clinical nurse educator.

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Strategies for daily livingEncourage your patient to keep her mind active by doing crossword puzzles orword games, or by attending lectures on subjects that interest her. To help hercope with cognitive deficits, offer these suggestions.• Train yourself to concentrate and focus. Minimize distractions and have con-versations in a quiet place.• Set up and follow routines.• Exercise, eat well, and pace yourself. Take breaks tailored to your concentra-tion span and get enough rest and sleep.• Break complex tasks into manageable pieces that you can tackle one at atime. For example, if you’re cleaning your house, wash the dishes before mov-ing on to a new task.• Repeat information aloud after someone gives it to you. Take notes.• Use a portable planner, personal organizer, or wall calendar to keep track ofappointments and upcoming events.• Keep a “memory notebook.” Use a journal to write down your daily scheduleand reminder notes about appointments and other commitments. You can alsouse it to keep track of signs and symptoms you want to discuss with yourhealthcare provider.• Leave messages for yourself on your answering machine as reminders.• Consider telling others what you’re going through. Seek professional counsel-ing if you feel extremely anxious or overwhelmed by your cognitive problems.7,8