Nick Mulcahy

March 21, 2014

Hollywood, Florida — Perhaps reflecting its growing importance in oncology, cognitive dysfunction was the subject of an oral presentation here at the annual meeting of the National Comprehensive Cancer Network (NCCN).

The condition, which is commonly called chemo brain, is included in the late effects section of the expanded NCCN Guidelines for Survivorship.

It is also an "area of intense research," said presenter Elizabeth Kvale, MD, medical director of the Supportive Care and Survivorship Clinic, at the University of Alabama, Birmingham.

"It is anticipated our understanding will expand substantially," she said about the expected yield of the new research.

However, currently, there is "limited" evidence to guide the management of this condition, Dr. Kvale added.

Much of the research has taken place in women with breast cancer.

Nevertheless, cancer-associated cognitive dysfunction impacts about 20% to 30% of all cancer survivors, said Dr. Kvale.

The effects typically last either months or a few years but, in some cases of "vulnerable" patients, they persist, she said.

Dr. Kvale offered the NCCN audience various testimonials from patients to illustrate the nature of the problem. "My mind is not as sharp as it was" and "I'm a software engineer and sometimes can't put 2 thoughts together to solve the puzzles that are the main part of my job," were 2 examples.

Public interest has driven the awareness about cognitive dysfunction, either disease-related or treatment-related, she said.

Dr. Kvale performed a Google search on the combined terms, "chemobrain" and "blog" and found 591,000 results.

She also showed clips of articles on chemo brain from the New York Times, Boston Globe, Bloomberg News, and USA Today. The media attention has been "significant," she said.

Studies include a 2012 meta-analysis of 17 longitudinal breast cancer trials that found patients treated with chemotherapy performed worse than those who did not receive it in terms of verbal ability and visuospatial ability (J Clin Oncol. 2012;34:3578-3587).

The findings may be complicated by the fact that this population may have pre-existing cognitive problems, acknowledged Dr. Kvale.

Indeed, at the 2012 San Antonio Breast Cancer Symposium, researchers reported finding that breast cancer patients scheduled to receive chemotherapy reported more severe fatigue before treatment than those in the control and preradiotherapy groups (P < .01).

However, there is now growing evidence that there is a "biological underpinning" of the symptoms of cognitive impairment, said Brenna McDonald, PsyD, in an email to Medscape Medical News.

She is associate professor of radiology and imaging sciences and neurology of the Indiana University School of Medicine, in Indianapolis.

"There are now multiple studies, including our own work, demonstrating that patient-reported concerns correlate with differences in brain structure and function after cancer treatment," said Dr. McDonald, who was not involved with the NCCN panel.

Not all chemotherapy patients will experience problems, said Dr. McDonald.

Older and less educated patients seem to be at greater risk after breast cancer chemotherapy, she observed.

Future research needs to risk-stratify patients to facilitate "prevention and intervention" efforts, Dr. McDonald added.

What to Do Clinically

Very little research has cemented the relationship between patient symptoms and objective measures of these problems, according to the NCCN.

For instance, the NCCN says the correlation between patient reports of cognitive decline and results of subsequent neuropsychological testing are "modest" according to the NCCN guideline on survivorship.

The NCCN guideline on survivorship reviews only one study on the subject. Therein, researchers found that, among 189 breast cancer survivors who complained about memory (about 20%), there was a significant association with results of neuropsychological tests and the complaints.

The guide advises that clinicians working with patients who complain of cognitive problems should inquire about their ability to pay attention, find words, remember things, think clearly, and perform daily activities.

Patients appreciate having their symptoms "validated," says the NCCN.

There is no effective screening tool for the problem. The Mini-Mental State Examination (MMSE) and other tools lack "adequate sensitivity for subtle decline in cognitive performance," according to the NCCN.

Importantly, such patients can be screened for other factors such as depression that may contribute to cognitive impairment.

Imaging studies are not recommended.

Aside from giving a patient a neuropsychological evaluation and optimizing management of depression or other problems such as sleep disturbance, the only other first-line intervention for these patients is occupational therapy, said Dr. Kvale.

In the second line, clinicians can consider use of psychostimulants, according to the NCCN guide.

National Comprehensive Cancer Network (NCCN) 19th Annual Conference. Presented March 15, 2014.

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