Newswise — When cancer patients begin chemotherapy, most anticipate some side effects: fatigue, nausea, hair loss. But nearly three-quarters of them will experience a lesser known side effect: a kind of mental fog that happens during and after treatment, dubbed chemo-brain.
A patient who had been able to juggle many things in her head suddenly might be unable to remember her own phone number, keep track of her appointments, or recall her assistant's first name, at least not without a lot more effort. For some patients, these symptoms persist for months and even years after treatment.
A decade ago, health care providers usually did not warn cancer patients about these cognitive changes. Patients' complaints about their new mental haze were often chalked up to the fatigue that comes with treatment, leaving patients doubting themselves and coping with these symptoms without support -symptoms that can affect their quality of life and sometimes their employment.
But now, thanks to the work of people like Jamie Myers, Ph.D., RN, research assistant professor at the University of Kansas School of Nursing and a researcher at the University of Kansas Cancer Center, chemo-brain is understood as its own condition, and cancer patients are routinely warned about possible cognitive difficulties: trouble recalling words, short-term memory loss, and difficulty concentrating and multi-tasking. "It used to be really frightening for patients, but now we're doing a better job of educating," said Myers. "That whole validation piece of a patient's experience is huge."
Myers would know. As an oncology clinical nurse specialist who worked in hospitals for more than 20 years, she administered chemotherapy to cancer patients. In those days, she was unaware of the cognitive changes many experience.
After she returned to the KU School of Nursing to pursue her doctorate, Myers attended symposium where she saw a panel discussion that included a breast cancer patient who was an ICU nurse. This patient said that she had not returned to the ICU after finishing chemotherapy because she didn't believe she could handle the job's mental challenges. "A lightbulb went off for me," said Myers. "I had done so much work with chemo, but I didn't educate patients about [chemo-brain], I didn't educate staff about it, and I thought, I want to do something to fix this."
Myers has spent the last decade researching the prevalence, possible causes, management and treatment of chemo-brain. Nearly 15 million Americans have had a cancer diagnosis, and that number is expected to reach 20 million by 2024. No FDA-approved medications exist to mitigate chemo-brain, and treatment consists of advising patients about how to cope with symptoms.
Chemo-brain affects all kinds of cancer patients, but breast cancer patients-a well-organized group with many survivors--have been the most outspoken. In 2012, Myers published a study describing the cognitive impairment of breast cancer patients as well as their coping mechanisms, which include simple strategies such as writing things down, doing one thing at a time, and exercising.
While these coping skills are helpful, they also might be why complaints of chemo-brain have been dismissed. When patients find ways to work around cognitive changes, they manage to score well on cognitive tests, which don't capture the extra effort the patient has had to make. Myers' 2012 study helped provide a framework for understanding these cognitive changes and a basis for developing educational tools for patients.
No single cause has been determined for chemo-brain, but there are several proposed mechanisms, including neurotoxicity from cancer treatment; genetic factors; chemotherapy-induced menopause for female patients; even psychological stress. And some cancer patients experience cognitive decline before treatment, which is why chemo-brain is somewhat of a misnomer. For these patients, the same failed DNA repair mechanism that led to their cancer might also be behind the cognitive decline.
Myers has focused on the role genetics and body mass index play on cognitive impairment in cancer patients. Excess weight causes inflammation, on top of the body's inflammatory response to the malignancy itself, which causes the body to produce more cytokines, proteins that help regulate the body's immune system's response. These cytokines impair learning and memory in animals, making cytokines a possible contributor to the mental decline of cancer patients. Some of Myers' preliminary analyses from saliva samples from breast cancer patients suggest that some people have a certain form of a gene that may stave off cognitive decline.
She regards her most significant finding as the role that exercise may play in mitigating against chemo-brain. In a study she and her colleagues published in 2015, excess weight (higher BMI) was associated with reports of worse cognitive function. However, exercise frequency was related to better reports of cognitive function-even for breast cancer patients with a high BMI. "This goes back to inflammation-exercise reduces inflammation, which helps with cognition," said Myers.
A study or three
That discovery is the basis for a study Myers is now conducting, funded by the Oncology Nursing Society Foundation, that looks at three interventions for cancer-related cognitive impairment: Qigong, a mindfulness-based exercise combining physical postures and breathing; gentle exercise without the mindfulness component, and a support group for women who have been treated for breast cancer. The researchers are convinced that exercise alone is helpful, and Myers is hopeful the mindfulness component can help even more.
This spring, Myers and Hannes Devos, Ph.D., assistant professor in the KU Department of Physical Therapy and Rehabilitation Science, were awarded a Frontiers pilot grant to use eye-tracking software to measure the cognitive effort breast cancer patients expend doing neurocognitive tasks. This software measures how much someone's pupils dilate as cognitive effort increases during mental tasks, such as coming up with as many words as they can that begin with a certain letter or remembering complex sequences of numbers and letters. The more effort it takes, the more the pupils dilate. In December, they were awarded the University of Kansas Cancer Center Fall pilot grant to expand their work to include a substudy visit for participants to do a driving simulation. Participants will perform a cognitive task while "driving" one of the medical center's new simulators developed by Abiodun Akinwuntan, Ph.D., MPH, MBA, dean of the KU School of Health Profession. These devices feature a car cockpit surrounded by three large computer screens that simulate road conditions. Myers and Devos believe the driving simulaition will add an important "real-life" component to the cognitive testing and measurement of cognitive effort by pupil dilation.
Moreover, KU Medical Center is collaborating with Cedars Sinai Medical Center in a psychoeducational study called "Emerging from the Haze" in which people with chemo-brain attend a weekly course for six weeks and learn to improve their cognitive function through guided relaxation, compensatory strategies for attention and memory problems, and behavioral strategies for negative thoughts. Participants have reported positive results, and the researchers are planning a larger study. They are also collecting saliva samples to identify genotypes that would make a patient more prone to chemo-brain.
Here at home, Myers is collaborating with Sally Maliski, Ph.D., RN, FAAN, dean of the KU School of Nursing, who is doing a prostate cancer study on men receiving androgen-deprivation therapy. That therapy suppresses testosterone, which can also impair cognitive function. Myers, who had learned about the research when she heard Maliski speak, set up a meeting with Maliski during which she suggested adding a cognitive component to the study. Maliski thought it was a great idea, and they were awarded a pilot project award from the KU Cancer Center and enrolled the first patients this year.
In the meantime, Myers encourages cancer patients who have cognitive problems to find a study to participate in, and to exercise. "We encourage them to find a form of exercise they can make a regular part of life," she said. "And then we also educate the patient and family on methods to cope with their situation."
Yet she believes the most important thing anyone can do for these patients is simply to validate their experience: "It's so common, and we just need to find a strategy that works for them."