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This article is part of our special October 2020 issue. Download the full issue here.
Relation
Oberoi S, Yang J, Woodgate RL, et al. Association of mindfulness-based interventions with anxiety severity in adults with cancer: a systematic review and meta-analysis.JAMA network opened. 2020;3(8):e2012598.
Study objective
The aim of this review was to determine whether mindfulness-based interventions (MBIs) improve anxiety in cancer patients.
Study design
The researchers conducted a systematic review and meta-analysis of clinical trials “extracted from MEDLINE, Embase, Cochrane Central Register of Controlled Trials, CINAHL, PsycINFO and SCOPUS from database inception to May 2019.”
All studies were randomized to MBI versus control group, which could be sham treatment, no intervention, waitlist participants, or usual care. Inclusion criteria were adults and children with cancer or receiving stem cell treatment for cancer.
Exclusion criteria included “observational, quasi-randomized, crossover, or cluster-randomized study designs and studies that did not report results relevant to this review.” No languages were excluded from data extraction. Interventions that included physical exercise, such as yoga, qigong, and tai chi, were excluded.
Participant
A total of 3,053 people were involved in the 28 studies included in the meta-analysis. All participants were adults as none of the studies involving subjects under 18 years of age met the review criteria. Participants could be in active treatment or post-treatment, with some receiving MBIs both during and after their treatments.
Study parameters
An initial search yielded 5,686 citations. After blinded screening and independent review by 2 of the authors of this publication, 27 studies ultimately met the review criteria. The researchers added one more study that they found by hand, for a total of 28 studies.
Primary outcome measures
The primary endpoint was severity of short-term anxiety up to 1 month after MBI. Secondary endpoints were anxiety, depression and quality of life in the medium term (1–6 months) and long term (6–12 months) after MBI.
Key insights
The most commonly used MBI across studies included mindfulness-based stress reduction (MBSR; 13 studies, 46.4%) and mindfulness-based cognitive therapy (MBCT; 6 studies, 21.4%). The median duration of MBIs was 8 weeks. The studies used 12 different anxiety scales, with Hospital Anxiety and Depression Scale A (HADS-A; 5 studies) and State-Trait Anxiety Inventory (STAI; 5 studies) being the most common. Breast cancer was by far the most represented cancer type in this review. Twelve studies (42.8%) focused exclusively on MBIs and breast cancer. Eleven recruited participants with various types of cancer, and of these, breast cancer was still the most common cancer in 10 of the studies.
MBIs significantly reduced short-term (0-1 month) anxiety (23 studies; 2,339 participants; SMD, −0.51; 95% CI, −0.70 to −0.33;I2=76%). A reduction in short-term anxiety was evident when HADS-A or the STAI scale was used in an independent statistical analysis of each.
MBIs also reduced the severity of medium-term (>1-6 months) anxiety (9 studies; 965 participants; SMD, −0.43; 95% CI, −0.68 to −0.18;I2=66%).
MBIs were not associated with long-term (>6 months-1 year) reductions in anxiety (2 studies; 403 participants; SMD, −0.02; 95% CI, −0.38 to 0.34;I2= 68%).
Additional results showed short-term reductions in depression (19 studies; 1,874 participants; SMD, −0.73; 95% CI, −1.00 to −0.46;I2=86%) and medium term (8 studies; 891 participants; SMD, −0.85; 95% CI, −1.35 to −0.35;I2= 91%), but not long-term (2 studies; 349 participants; SMD, −0.96; 95% CI, −2.38 to 0.46;I2= 97%).
MBIs were also associated with improvement in overall health-related quality of life (HRQOL) scores both short-term (9 studies; 1,108 participants; SMD, 0.51; 95% CI, 0.20 to 0.82;I2=82%) and medium term (5 studies; 771 participants; SMD, 0.29; 95% CI, 0.06 to 0.52;I2=57%) The single study that tracked HRQOL long-term showed no benefit (1 study; 153 participants; WMD, 0.78; 95% CI, −5.98 to 7.54).
Practice implications
Mindfulness is a concept that dates back thousands of years to ancient Eastern philosophy and is generally associated with the Buddhist tradition. Jon Kabat-Zinn, PhD, one of the pioneers of the modern mindfulness movement, describes mindfulness as “the awareness that arises from intentionally paying attention, in the present moment, to the unfolding of experiences from moment to moment, without judgment.”1Kabat-Zinn was one of the first people to study mindfulness in the context of health and well-being. After graduating from the Massachusetts Institute of Technology (MIT), he founded a stress reduction clinic at the University of Massachusetts Medical School. In 1979, he created Mindfulness-Based Stress Reduction (MBSR), an 8-week group course. The program teaches mindfulness as a meditation practice, but also as a way of life.2He then began researching the role of mindfulness in chronic pain and immunity. Kabat-Zinn studied the effects of the MBSR program in breast and prostate cancer patients, the first research of its kind.
Although thousands of studies have been conducted on mindfulness in cancer patients, most show only moderate improvement. For example, mindfulness was no longer able to produce the desired result compared to exercise.
Several studies have shown that mindfulness benefits cancer patients. A systematic review conducted in 2019 by Ngamkham, Holden, and Smith found that mindfulness interventions can reduce cancer-related pain and improve quality of life.3A 2014 Canadian study confirmed the findings of Nobel Prize winner and discoverer of the enzyme telomerase, Elizabeth Blackburn, that mindfulness interventions actually affect telomere length.4In the Canadian study, breast cancer survivors who participated in a Mindfulness-based Cancer Recovery (MBCR) program or group therapy maintained telomere length, while those who did not participate in any program experienced telomere shortening, a sign of cellular aging.5
The study currently reviewed is a meta-analysis that provides some evidence that MBIs reduce anxiety in cancer patients and is a valuable contribution due to the larger number of subjects (N = 3,053) as well as the inclusion of all cancer types. Other checks were carried out. A 2017 meta-analysis of 1,709 breast cancer patients examined how MBSR/MBCT had significant effects on quality of life, fatigue, sleep, stress, anxiety and depression.6Another meta-analysis in 2015 confirmed the effectiveness of MBIs in reducing anxiety and depression.7
Despite the amount of evidence we now have regarding the therapeutic effects of mindfulness, there are still critics of mindfulness. Although thousands of studies have been conducted on mindfulness in cancer patients, most show only moderate improvement. For example, mindfulness was no longer able to produce the desired result compared to exercise.8Mindfulness research is criticized for many reasons. Some include studies with small sample sizes, lack of diversity in patients, and lack of diversity in cancer types. Many of the study designs also lack randomized controls and long-term follow-up.9
However, many oncology centers offer mindfulness, usually in the form of MBSR or MBCT. Programs typically last 8 weeks, with a weekly group session covering various aspects of mindfulness and daily individual exercises conducted at home. Common techniques include non-judgment, patience, kindness and acceptance.10
Decades of research provide a case for the use of mindfulness in cancer patients, but more research is needed for widespread acceptance of its use. While the academic debate about the effectiveness of MBIs continues, few will dispute that reducing anxiety and depression and improving quality of life can change a patient's life for the better.