Today we are discussing cancer-related cognitive impairment, also known as “chemo fog” or “chemo brain” which can be connected either to specific cancer treatments or to a cancer diagnosis. This impairment can include detrimental effect on memory, attention, the ability to make decisions, plan and execute tasks, and negatively impacts quality of life of patients.
We are speaking with Patricia Ganz, MD and Tracy D. Vannorsdall, PhD. Ganz is a medical oncologist and professor of health policy and management at the Fielding School of Public Health at UCLA, and director of the Center for Cancer Prevention & Control Research at the Jonsson Comprehensive Cancer Center, in Los Angeles. She studies cognitive effects of cancer treatment, specifically in breast cancer patients.
Vannorsdall, is a clinical neuropsychologist and assistant professor of psychiatry and behavioral sciences at Johns Hopkins University in Baltimore whose research includes improving cognitive functioning in cancer patients at risk for neuropsychological decline. Vannorsdall sees both cancer patients and survivors to address their cancer-related cognitive impairment.
—Interviewed by Anna Azvolinsky
Cancer Network: First, for both of you, could you talk about where there is a formal definition or way to evaluate cancer-related cognitive impairment? What does this term mean exactly?
Dr. Ganz: This is something that has been evolving over time because when this particular entity was first described about 20 years ago, typically in women who were either getting high-dose chemotherapy for breast cancer or getting chemotherapy as an adjuvant therapy. These patients began to complain of having persistent cognitive changes, not being able to multi-task and after receiving this therapy frequently they also had fatigue as a common treatment problem.
Over time we began to see that other groups of patients also had these complaints and while it was mostly associated with fairly intensive cancer treatments, we also began to see issues related to hormonal treatments for breast cancer and prostate cancer. In some patients, having cancer alone can cause some of these symptoms. This is a complicated syndrome where the etiology and the mechanisms are complex, but it is something that we see because we have so many cancer survivors who try to go back and do their work and continue on with their lives and find that it is challenging.
Dr. Vannorsdall: We are referred patients who are in the process of that transition. They have wrapped up their acute treatment, and they are trying to re-enter their former life roles. They are struggling to be as efficient and effective as they had been prior to their diagnosis and treatment. Often I will met with the patient, and sometimes with their family to discuss the types of cognitive difficulties that they are experiencing and how it is affecting their lives.
Our patients complete a battery of tests that look at functioning across a range of different thinking skills including attention, working memory, learning, recall, executive functioning, and language skills like word finding. We compare how the patient is doing vs expectation based on his or her demographic characteristics.
What we are looking for in the clinical setting is a pattern of weaknesses on testing and lower scores than are expected given a person’s background and linking to how they are having difficulties in everyday life. From a research perspective, we tend to think, more strictly, of two or more scores that are at least 1.5 standard deviations below the mean on a cognitive test battery or a single score that is at least 2 standard deviations below the mean. So, there are various ways to detect cognitive difficulties and to define that based on whether we are looking clinically or in a research setting.
Cancer Network: From both of your experiences, what are some of the cognitive changes that cancer patients can experience that are related to their cancer therapies? Tracy, you mentioned the changes on test scores, but what are the everyday life changes that patients say they experience?
Dr. Vannorsdall: The words efficiency and consistency are really common in my practice. Patients will often come in and say, ‘I can do it, I can get back into my former roles but I am not as efficient as I used to be. Things are falling through the cracks and I am forgetting things that I think I would have been able to remember previously. I am not paying attention as well and not juggling the complexities of everyday life.’ So, the executive function, planning and problem-solving and multi-tasking and also coming up with the right word in conversation. Word-finding difficulties are extremely common and very frustrating for the patients that I see.
Dr. Ganz: Just to echo what Tracy said, some of these changes are probably related to hormonal changes, particularly in women with breast cancer or other patients who may become prematurely menopausal from chemotherapy because estrogen has an important role in verbal word fluency and word finding. Any woman going through menopause will notice that she may have difficulties like this. These symptoms become more pronounced either with premature menopause induced by chemotherapy or sometimes with endocrine therapy.
Cancer Network: A cancer diagnosis is very stressful. Can both of you talk about what we know about cancer patients experience with cognitive impairment that might not even be related to their therapy, but just the burden of receiving the diagnosis? Are there patients that are more susceptible to this?
Dr. Ganz: Certainly both anxiety and depression can lead to difficulties in concentration, focusing, and planning, some of the skills just mentioned by Tracy. We find that sleep disturbance is a problem, as patients getting chemotherapy are often getting a lot of medications that may make them have difficulties sleeping. Managing some of these symptoms may in fact help with cognitive complaints.
Dr. Vannorsdall: I would add that anxiety and depression do contribute to cognitive difficulties in anyone, even if you take cancer out of the picture. But with cancer patients, they are also particularly important from the perspective of treatment engagement. There are some data to suggest that depressed patients are more likely to be non-adherent and that they receive fewer of their prescribed chemotherapy treatments and may be less likely to engage in endocrine therapies and are also less likely to engage in health-promoting behaviors like physical activity, smoking cessation, weight management. All of these health-promoting behaviors are important predictors of cancer recurrence. The mood and anxiety issues affect cognitive functioning, and can also affect treatment engagement as well.
Cancer Network: Dr. Ganz, you’ve studied cognitive function among breast cancer patients and survivors. Could you highlight some of the important findings from your studies?
Dr. Ganz: I think one of the things to note is that breast cancer is a disease, more often, of well-educated, upper middle class women. That is not to say that anyone can't get breast cancer, but these women tend to be very high functioning and as a result, very subtle changes in their performance after their cancer treatments may cause them concern and anxiety about how they are performing.
While we heard about standardized test changes that we can pick up upon doing neuro-psychological testing, often these very well educated individuals would have been above the mean in their performance to begin with and a change may be significant for them even though they may score on a neuro-psychological test in the normal range. Some of the work we’ve done has really begun to emphasize subjective or self-reported complaints. If you use certain questionnaires that get at aspects of language or executive performance, you can show that the patient’s self-reported concerns and complaints do map on some of those neuro-psychological test scores even though the scores may not absolutely be in the abnormal range.
Some of what we have been promoting is to listen to the patient, just as we would accept complaints about pain or insomnia from the patient, complaints about cognitive difficulties are also important to recognize. These may not lead to big changes on neuro-psychological testing, but may be important.
I think the issue we face is that everyone getting treatment may have disruption in cognition which we would expect, given everything that is going on, but if it doesn’t get better over the course of the year after treatment, then that is when we would be concerned about more persistent changes. Then, we want to look into this by having a consultation with a neuro-psychologist, giving the patient an opportunity to have rehabilitation strategies that we can teach them to help deal with.
Cancer Network: Dr. Vannorsdall, from your experience with cancer patients, are there certain approaches that are known to improve cognitive functioning or at least to stave off some of the cognitive decline during and after treatment?
Dr. Vannorsdall: The most empirical data is on physical exercise, and that is my most common recommendation. The data indicate that exercise is associated with improvements in both subjective cognitive complaints and objective cognitive changes. Patients who begin to exercise experience improved quality of life, mood, anxiety, and fatigue. Exercise can also indirectly improve cognitive functioning by addressing some of the other medical contributors to poor cognition like hypertension and diabetes.
I think what is really key is that the exercise doesn’t need to be particularly intensive or prolonged to yield benefits. Studies have shown improvements within a month of fairly regular Tai Chi engagement for example. Patients don’t need to be training for a marathon, they can be engaging in physical activities that are suitable for their current level of stamina. There are also compensatory strategies that can be quite helpful. These are sometimes based on results of formal neuro-psychological assessment and focus on using areas of cognitive strength to compensate for areas of weakness as well as figuring out ways to structure the environment to facilitate cognitive facility and effectiveness.
Some of our patients find cognitive rehabilitation to be helpful. This is the practice of repetitive and more mentally challenging tasks. We do think that in part this tends to work because of patients’ increase in self-efficacy. They gain confidence back in their cognitive skills, which can be very helpful. And of course addressing the comorbid depression, anxiety, and sleep disturbance that Patti mentioned is also key to help our patients get back to their normal level of cognitive functioning.
Cancer Network: Lastly, are there resources for both clinicians and patients you could share on cancer-related cognitive impairment?
Dr. Ganz: Sometimes this is challenging. Again, being in a large city and a university setting, I have a number of individuals I can refer to but I would say, in general, it is important for the patient to speak up and mention these changes to their physician. Often, this is not discussed at all, even though patients frequently complain about this and again, it often occurs during the survivorship time when the patient may feel that the doctor is so busy seeing sick patients who are receiving treatment and doesn’t want to burden the doctor.
So, encouraging patients to at least discuss this with their physicians and on the physician’s side, they need to make an assessment of what else may be going on, is the patient depressed? This is something that we can do something about, by referring patients to the appropriate clinician. Is the patient not sleeping? In the case of women with breast cancer, we often disrupt their sleep with symptoms and nighttime awakening. Managing those symptoms would give the woman a better chance to have a good night’s sleep and feel better in terms of cognitive function. Or, basically insomnia that is pre-existing before the cancer or comes on after the cancer diagnosis and treatments like Tai Chi or acupuncture or cognitive behavioral therapy for insomnia may be very helpful for managing these symptoms.
Once the physician has ruled out management of those symptoms as being an opportunity to get this under control, the neuro-psychological consultations can be very important. So, as with the other survivorship concerns, lining up the clinicians who can help with management of a variety of symptoms is very important.
Dr. Vannorsdall: I completely agree. Developing a network of referral sources can be quite helpful. Our patients who are looking for mental health providers, sometimes in conjunction with their treatment professionals, or on their own can often find local resources from the American Psychological Association website or the American Academy of Clinical Neuropsychology website that both list providers by region. There are also websites like the Association of Oncology social work that can provide a list of resources for people with cancer and their families who are looking for mental health providers and neuro-psychological service providers. There are wonderful books like ‘Improving Cognitive Functioning after Cancer Care’ by neuropsychologist Shelly Kesler that is a great patient-geared book that reviews cognitive difficulties during and after cancer and their mechanisms and treatment approaches.
Cancer Network: Thank you so much to both of you for joining us.
Dr. Ganz: Thank you.
Dr. Vannorsdall: Thank you.