Guest Editor’s Note: Cancer-related cognitive difficulties, experienced by many cancer survivors, include perceived or objective deficits in memory, attention, and concentration, which can negatively impact quality of life. Given the important role that healthful sleep plays in cognitive processes, addressing sleep difficulties to improve cognitive function is a promising area of research. In this installment of The ASCO Post’s Integrative Oncology series, Kevin T. Liou, MD, describes previous study findings in the evaluation of cognitive outcomes with acupuncture vs cognitive behavioral therapy for insomnia in cancer survivors.
Kevin T. Liou, MD
Cognitive Dysfunction in Cancer Survivors
Nearly four in five cancer survivors experience cognitive difficulties because of cancer and its treatments.1 Characterized by problems with memory, attention, executive function, and psychomotor skills, cancer-related cognitive dysfunction impairs quality of life and threatens the functional independence of cancer survivors.2 Despite the prevalence and disruptive nature of cancer-related cognitive dysfunction, optimal treatments are lacking for this condition.
Medications, such as modafinil, methylphenidate, memantine, and donepezil, the herb Ginkgo biloba, and estradiol, have all demonstrated mixed results.2,3 Due to growing concerns about polypharmacy in cancer survivors,4 the National Comprehensive Cancer Network recommends nonpharmacologic interventions.5 Cognitive rehabilitation, cognitive behavioral therapy, physical activity, yoga, qi gong, and mindfulness techniques have shown benefit in terms of cognitive function, but these findings need to be confirmed in larger, rigorously designed trials.6
Therapeutic Approach to Improve Cognitive Function
Although cancer-related cognitive dysfunction is sometimes described as “chemo-brain,” emerging evidence suggests that other factors besides chemotherapy may contribute to impaired cognitive functioning after a cancer diagnosis and treatment. It is well documented that healthy sleep is required for memory consolidation and other key cognitive processes.7-9 Studies have also demonstrated significant associations between sleep disturbances and cognitive difficulties in cancer populations,10-13 leading to the hypothesis of sleep as a potential therapeutic target for cancer-related cognitive dysfunction.
GUEST EDITOR
Jun J. Mao, MD, MSCE
Integrative Oncology is guest edited by Jun J. Mao, MD, MSCE, Laurance S. Rockefeller Chair in Integrative Medicine and Chief of Integrative Medicine Service at Memorial Sloan Kettering Cancer Center, New York.
To explore whether treating sleep disturbances can improve cognitive function, integrative medicine researchers at Memorial Sloan Kettering Cancer Center (MSK), New York, conducted a secondary analysis of data from their previous randomized clinical trial, which compared the effectiveness of two evidence-based interventions for insomnia in cancer survivors. Trial participants were survivors of any cancer type or stage who had completed primary cancer treatment and had a clinical diagnosis of insomnia. A total of 160 survivors were randomly assigned to receive cognitive behavioral therapy for insomnia (CBT-I) or acupuncture.
CBT-I is a first-line treatment that includes sleep restriction, stimulus control, cognitive restructuring, relaxation training, and sleep hygiene education. Acupuncture is a therapeutic modality derived from traditional Chinese medicine that involves the insertion of thin, sterile, single-use, metallic needles into specific points on the body. Both CBT-I and acupuncture have produced clinically meaningful reductions in the severity of insomnia.14
For the secondary analysis, the researchers examined cognitive outcomes from a subgroup of 99 trial participants who reported baseline cognitive difficulties and participated in optional cognitive testing.15 The Buschke Selective Reminding Test was used to assess objective attention, learning, and memory. (The Buschke Selective Reminding Test measures verbal learning and memory through the use of a list-learning procedure over multiple trials.) The Brown Attention-Deficit Disorder Scale was used to assess subjective cognitive function.
Acupuncture produced short- and long-term improvements in objective attention, learning, and memory, whereas CBT-I produced a long-term improvement in objective attention alone. Both interventions produced short- and long-term improvements in subjective cognitive function. In the acupuncture group, patients with clinically meaningful responses in insomnia symptoms demonstrated a greater improvement in subjective cognitive function, compared with those without clinically meaningful insomnia responses. In the CBT-I group, similar improvements in subjective cognitive function were observed regardless of the response in insomnia symptoms.
Clinical Implications
Both CBT-I and acupuncture demonstrated potential benefits in improving objective and subjective cognitive function in cancer survivors with insomnia. As a secondary analysis of a randomized trial, the study was not powered to detect differences between the two treatments. However, preliminary findings suggest that CBT-I is particularly beneficial for subjective cognitive function, whereas acupuncture appears promising for objective measures of memory and learning. Based on the study results, acupuncture may produce cognitive benefits by improving sleep, but the mechanisms underlying CBT-I’s effects on cognition need to be further elucidated.
Although additional research is needed, cancer survivors struggling with sleep and cognitive difficulties may consider CBT-I or acupuncture as a potential treatment option, along with other nonpharmacologic interventions. Notably, both treatments have a relatively favorable safety profile.
Currently, integrative medicine researchers are building on these findings by collaborating with their MSK colleagues in the Neurocognitive Research Laboratory on a National Cancer Institute–funded clinical trial. The study seeks to evaluate the effects and mechanisms of acupuncture on cancer-related cognitive dysfunction in breast cancer survivors. Findings from this trial may inform evidence-based, personalized treatment of cancer-related cognitive dysfunction.
Dr. Liou is an Integrative Medicine Specialist at Memorial Sloan Kettering Cancer Center, New York.
DISCLOSURE: Dr. Liou reported no conflicts of interest.
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