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, Integrative Medicine Service, Memorial Sloan Kettering Cancer Center, New York.
“Mindfulness” has gained significant popularity in the lay press in recent years. Is a mindfulness-based approach useful for patients with cancer? In this article, Dr. Carlson summarizes the current evidence for and limitations of mindfulness-based practices, and the physical and psychological benefits they produce, in oncologic care.
Mindfulness can be defined as paying attention, on purpose, with a nonjudgmental attitude. It is both a way of being in the world (one can be more or less mindful at any given time) and a practice (mindfulness meditation) that develops the skill or ability to be mindful.
There are generally three main components of mindfulness, captured in the IAA model proposed by Shapiro et al1: intention, attention, and attitude. One first develops the intention to try to be more mindful (or any range of possible intentions), and this serves as a sustaining motivation for the practice. Attention training is the core of the practice of mindfulness meditation, which involves honing the ability to notice when attention has wandered and redirect it to elements of present-moment awareness. Attitudes of being nonjudgmental, accepting of a wide range of experience, curious, kind, and compassionate toward oneself are also emphasized.
Mindfulness can be defined as paying attention, on purpose, with a nonjudgmental attitude.— Linda E. Carlson, PhD, RPsych
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Mindfulness training in oncology settings is often delivered through programs such as mindfulness-based stress reduction or mindfulness-based cancer recovery, collectively referred to as mindfulness-based interventions. They are typically 8-week group programs that consist of weekly meetings and daily home practice of a variety of mindfulness and yoga exercises. We first offered a mindfulness-based cancer recovery program to people with cancer 20 years ago due to its potential ability to address common concerns including loss of control; uncertainty about the future; distress; depression; anxiety; fear of cancer recurrence; and unpleasant physical symptoms such as fatigue, pain, and sleep disturbance.2
There has been an exponential growth of both academic and lay interest in mindfulness training. It has also been applied in health care for patients with a wide range of mental and physical health conditions, crossing diagnostic boundaries with alacrity. This proliferation has not surprisingly resulted in some backlash and skepticism about the value of such broad application. Scientists have cautioned audiences not to reach beyond the research findings, which are still in the early stages in many areas.3
These cautions are sound for many areas of mindfulness research and application. Yet in the area of cancer care, the body of research is more robust than in many others, with a number of large well-designed studies and meta-analyses providing consistent and promising results.
Current Evidence Base
Our group published the first clinical trial of mindfulness in cancer care in 2000,4 finding large improvements in anger, anxiety, depression, and many physical and psychological stress symptoms in a sample of 89 people with a variety of cancer diagnoses and stages. Over the years, at least 30 other randomized controlled trials and over 100 studies using other methodologies such as pre-post assessments, nonrandomized comparison groups, or qualitative designs have been conducted with cancer populations. Six reviews of randomized controlled trials using meta-analytic methods5-10 and another 11 systematic and narrative reviews evaluating the efficacy of mindfulness-based interventions for various groups of cancer survivors across a wide range of outcomes11-21 have also been published in the past 10 years.
Results show promise for mindfulness-based interventions to treat common psychological problems such as anxiety, stress, and depression in cancer survivors and to improve overall quality of life.— Linda E. Carlson, PhD, RPsych
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Much of this work has been conducted with breast cancer survivors. For example, a 2017 meta-analysis compiling 10 randomized controlled trials including 1,709 breast cancer survivors indicated significant but small effects on health-related quality of life, fatigue, sleep, stress, anxiety, and depression (effect sizes [ES] = 0.21–.034).5 Six months after baseline, effects on anxiety and depression continued to be significant, and up to 12 months after baseline, the effect on anxiety was still significant.
An earlier meta-analysis in breast cancer including both randomized controlled trials and other study designs found larger effect sizes for mindfulness-based stress reduction on stress (ES = 0.71), depression (ES = 0.58), and anxiety (ES = 0.73) across 9 studies.6 The largest studies to date randomly assigned 32222,23 and 33624 women with breast cancer into treatment or usual-care control groups. Greater improvements were reported post-program on somatic symptoms and overall distress23 as well as sleep,22 anxiety, fear of cancer recurrence, and fatigue24 in the mindfulness groups compared to control, and women with the highest levels of stress at baseline experienced the greatest benefit from the program.24
A 2017 systematic review more broadly included 13 studies of all cancer types and clinical trial designs published since 2009.21 This review reported that 9 of the 13 studies demonstrated positive changes in psychological or physiologic outcome measures related to stress, whereas 4 studies had mixed results. The most consistent positive effects across studies were on measures of stress, mood disturbance, anxiety, quality of life, cortisol profiles, and blood pressure.
It should be made clear to participants that mindfulness training is not intended to replace standard psychiatric care.— Linda E. Carlson, PhD, RPsych
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A limitation in this body of research is that not many studies have compared mindfulness-based interventions to other active interventions that may appeal to patients. Two notable exceptions are reports by Henderson et al, who compared mindfulness-based stress reduction to a nutrition education program and usual supportive care in 172 breast cancer patients,25 and Carlson et al, who compared mindfulness-based cancer recovery to supportive expressive group therapy and a minimal intervention control group in 271 distressed breast cancer survivors.26
Henderson et al found greater improvement in quality of life, coping, meaningfulness, depression, paranoid ideation, hostility, anxiety, unhappiness, and emotional control in the mindfulness participants compared to the other two groups.25 Similarly, Carlson et al reported greater post-program benefits across outcomes of stress, quality of life, and social support in the mindfulness group over supportive expressive group therapy recipients and controls,26 as well as long-term sustained greater improvements on fatigue, anxiety, confusion, tension, sympathetic arousal, cognitive symptoms, emotional and functional quality of life, social support, spirituality, and posttraumatic growth relative to those in the supportive expressive group therapy group.27
In summary, results show promise for mindfulness-based interventions to treat common psychological problems such as anxiety, stress, and depression in cancer survivors and to improve overall quality of life.
There are no reports of adverse events within the oncology literature relating to the application of mindfulness training; however, this may partially be the result of a lack of routine monitoring. In the larger meditation research community, there has been an ongoing effort to document and classify potential risks to participants and calls to more systematically measure and report adverse events.3
Clinical guidelines in mindfulness training programs suggest the exclusion of individuals with current suicidality and/or current psychiatric disorder and warn that individuals with trauma histories may have an increased likelihood of suicidality, depression, negative emotions, and flashbacks during meditation.28,29 In addition, it should be made clear to participants that mindfulness training is not intended to replace standard psychiatric care, but rather, can be a useful adjunct or approbation for those with subclinical symptomatology.
Recommendations for Future Research
Limitations often cited in this literature include small sample sizes, self-selection of participants, lack of diversity, inability to generalize beyond breast cancer and high socioeconomic status groups, reliance on patient-reported outcomes (which may be susceptible to social desirability and demand characteristics), lack of studies comparing mindfulness-based interventions to other active interventions, and lack of long-term follow-up.
Recommendations generally follow to expand to more diverse participant samples, including more advanced cancers and palliative care; include more men in studies; compare mindfulness programs to other efficacious interventions; and include more rigor in outcome evaluations. In addition, to improve the reach of mindfulness-based interventions, studies of online and mobile app–delivered interventions are underway. ■
Dr. Carlson is Professor, Oncology and Psychology, University of Calgary, and also holds the Enbridge Research Chair in Psychosocial Oncology, co-funded by the Canadian Cancer Society Alberta/NWT Division and Alberta Cancer Foundation, Alberta, Canada.
DISCLOSURE: Dr. Carlson reported no conflicts of interest.
Editor’s note: For more on Mindfulness, view the talk by Linda E. Carlson, PhD, Psych, “A Key for Personal and Collective Evolution,” available at https://bit.ly/2tDZXQ7.
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