The Effects of Cognitive-Behavioral Stress Management for Breast Cancer Patients: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

This meta-analysis pooled results from 18 randomized controlled trials (RCTs) testing cognitive-behavioral stress management (CBSM) against control conditions. The CBSM intervention combined two components:

**Cognitive-behavioral therapy elements:** cognitive reframing, cognitive restructuring, coping skills training, assertiveness training, anger management, and optimizing social support use.

**Stress management/relaxation training:** progressive muscle relaxation, guided visual imagery, meditation, and deep breathing exercises.

The control conditions were:

1-day psychoeducation seminar (most common)

Wait-list control

Standard care

The primary outcomes examined were:

**Psychological:** anxiety, depression, perceived stress, mood disturbance, positive affect, negative mood, benefit-finding, thought intrusion/avoidance

**Physiological:** serum cortisol levels

**Coping-related:** relaxation (measured by the Measure of Current Status relaxation subscale), negative mood regulation

**Total sample:** 2,564 women with breast cancer (1,285 in intervention groups, 1,279 in control groups)

**Age range:** Mean ages across studies ranged from 31 to 73 years

**Setting:** 17 of 18 RCTs were conducted in the United States; 1 was conducted in Ireland

**Diagnosis:** All participants were women definitively diagnosed with breast cancer based on clinical, radiological, and pathological examinations

**Treatment status:** Participants were at various stages of treatment (surgery, chemotherapy, radiation, hormonal therapy) or post-treatment

**Exclusion criteria:** Studies were excluded if they scored "high risk" on the Cochrane Risk of Bias tool

The meta-analysis used standardized outcome measures with established reliability and validity:

**Anxiety:** Hospital Anxiety and Depression Scale (HADS, α = 0.75–0.86); Hamilton Rating Scale for Anxiety (HAMA, reliability coefficient = 0.93)

**Depression:** Center for Epidemiologic Studies Depression Scale (CES-D, α = 0.90); HADS depression subscale

**Perceived stress:** Perceived Stress Scale (PSS, α > 0.82, test-retest = 0.77)

**Mood:** Profile of Mood States (POMS, α = 0.90, test-retest = 0.60); Positive and Negative Affect Schedule – Short Form (α = 0.84); Affect Balance Scale (α = 0.95)

**Relaxation:** Measure of Current Status relaxation subscale (MOCS relaxation, α = 0.71)

**Benefit-finding:** Benefit Finding Scale (BFS, α = 0.95)

**Negative mood regulation:** Negative Mood Regulation Scale (NMR, α = 0.90)

**Intrusion/avoidance:** Impact of Event Scale (IES, test-retest = 0.87, split-half = 0.86, α = 0.92)

**Cortisol:** Serum cortisol levels (biological assay)

**Quality of life:** Functional Assessment of Cancer Therapy – Breast (FACT-B, α = 0.94)

**Optimism:** Silver Lining Questionnaire (SLQ, α = 0.93)

**Design:** This is a systematic review and meta-analysis of randomized controlled trials (RCTs). Meta-analysis is a statistical technique that combines results from multiple independent studies to produce a single pooled estimate of effect size, increasing statistical power and precision.

**Search strategy:** The authors searched 8 electronic databases (PubMed, EMBASE, Cochrane Database, ScienceDirect, MEDLINE, CENTRAL, CINAHL, PsycNET) for RCTs published up to November 21, 2017. They also searched reference lists and unpublished documents (degree papers, conference proceedings, registered clinical trials).

**Inclusion criteria:**

Must be an RCT

Participants must have confirmed breast cancer diagnosis

CBSM intervention must include both cognitive-behavioral therapy elements AND stress management/relaxation training

Must report at least one relevant outcome measure

**Exclusion criteria:** Studies rated "high risk" on the Cochrane Risk of Bias tool were excluded (1 study excluded for this reason).

**Quality assessment:** Two independent reviewers assessed each study using the Cochrane Collaboration's Risk of Bias Tool, evaluating: randomization sequence generation, allocation concealment, blinding of participants/personnel, blinded outcome assessment, incomplete outcome data, selective outcome reporting, and other biases. Each domain rated as "low risk," "high risk," or "unclear risk."

**Statistical methods:**

Used weighted mean differences (WMD) with 95% confidence intervals (CIs)

Fixed-effects models used when heterogeneity was low (I² ≤ 25%)

Random-effects models used when heterogeneity was moderate-to-substantial (I² > 50%)

Studies with I² > 75% were not merged with others

P < 0.05 considered statistically significant

**What this design can prove:** Meta-analyses of RCTs provide the highest level of evidence for causal inference. Because all included studies were RCTs with random assignment, the pooled results can establish that CBSM causes changes in the measured outcomes, assuming adequate study quality.

**What this design cannot prove:**

Cannot determine which specific component of CBSM (cognitive therapy vs. relaxation training vs. group support) is responsible for effects

Cannot determine optimal dose, frequency, or duration of CBSM

Cannot determine long-term durability of effects beyond study endpoints

Cannot determine if effects generalize to men with breast cancer or other cancer types

Cannot rule out publication bias (studies with null results may be unpublished)

**Major methodological weaknesses:**

Only 1 of 18 RCTs reported adequate allocation concealment (using sequentially numbered envelopes)

None of the trials blinded participants or therapists (impossible given the nature of the intervention)

10 of 18 RCTs reported blinded outcome assessment

Only 5 of 18 RCTs used intention-to-treat analysis

11 of 18 RCTs were rated "unclear risk" on the Cochrane tool

All but one study conducted in the United States, limiting cultural generalizability

High heterogeneity for some outcomes (e.g., anxiety, depression), suggesting inconsistent effects across studies

Most studies used face-to-face group delivery; only 2 used web-based delivery, limiting generalizability to remote formats

**Primary outcomes (statistically significant effects):**

**Relaxation (MOCS relaxation):** CBSM significantly increased relaxation scores compared to control (WMD = 0.46, 95% CI: 0.20 to 0.72, P < 0.001). Based on 4 RCTs with 468 participants. Low heterogeneity (I² = 0%).

**Benefit-finding (BFS):** CBSM significantly increased benefit-finding (WMD = 0.27, 95% CI: 0.05 to 0.49, P = 0.02). Based on 3 RCTs with 460 participants. Low heterogeneity (I² = 0%).

**Positive affect:** CBSM significantly increased positive affect (WMD = 0.27, 95% CI: 0.05 to 0.49, P = 0.02). Based on 3 RCTs with 460 participants. Low heterogeneity (I² = 0%).

**Serum cortisol:** CBSM significantly reduced serum cortisol levels (WMD = -0.18, 95% CI: -0.33 to -0.03, P = 0.02). Based on 3 RCTs with 240 participants. Low heterogeneity (I² = 0%).

**Anxiety:** CBSM significantly reduced anxiety (Standardized Mean Difference = -0.30, 95% CI: -0.54 to -0.06, P = 0.01). Based on 7 RCTs with 1,052 participants. Substantial heterogeneity (I² = 67%).

**Depression:** CBSM significantly reduced depression (SMD = -0.28, 95% CI: -0.49 to -0.07, P = 0.009). Based on 8 RCTs with 1,196 participants. Substantial heterogeneity (I² = 63%).

**Thought intrusion (IES intrusion):** CBSM significantly reduced intrusive thoughts (WMD = -0.25, 95% CI: -0.47 to -0.03, P = 0.03). Based on 4 RCTs with 468 participants. Low heterogeneity (I² = 0%).

**Thought avoidance (IES avoidance):** CBSM significantly reduced avoidance (WMD = -0.23, 95% CI: -0.45 to -0.01, P = 0.04). Based on 4 RCTs with 468 participants. Low heterogeneity (I² = 0%).

**Negative mood:** CBSM significantly reduced negative mood (WMD = -0.27, 95% CI: -0.49 to -0.05, P = 0.02). Based on 3 RCTs with 460 participants. Low heterogeneity (I² = 0%).

**Primary outcomes (non-significant effects):**

**Perceived stress (PSS):** CBSM showed no significant effect on perceived stress (WMD = -0.08, 95% CI: -0.30 to 0.14, P = 0.47). Based on 4 RCTs with 468 participants. Low heterogeneity (I² = 0%).

**Mood disturbance (POMS total):** CBSM showed no significant effect on overall mood disturbance (WMD = -0.14, 95% CI: -0.36 to 0.08, P = 0.21). Based on 3 RCTs with 460 participants. Low heterogeneity (I² = 0%).

**Secondary outcomes (not meta-analyzed due to insufficient data):**

Quality of life (FACT-B): Mixed results across individual studies

Negative mood regulation (NMR): Improved in some individual studies

Optimism (SLQ): Improved in the single Irish study

The effects of CBSM were small-to-moderate in size, translating to the following real-world changes:

**Relaxation:** A 0.46-point increase on the MOCS relaxation subscale (0–4 scale). This is roughly equivalent to moving from "I can relax a little" to "I can relax moderately well" — about a half-step improvement on a 5-point scale.

**Anxiety and depression:** Standardized mean differences of -0.30 and -0.28 respectively. This means the average person in the CBSM group scored about 0.3 standard deviations lower on anxiety and depression scales than the average control participant. In practical terms, this might translate to a 2–3 point reduction on the HADS (0–21 scale) — enough to move from "borderline abnormal" to "normal" range for some individuals.

**Cortisol:** A 0.18 standard deviation reduction in serum cortisol. This is a modest biological effect — roughly equivalent to the cortisol reduction seen after 20 minutes of moderate exercise or a single session of mindfulness meditation.

**Thought intrusion/avoidance:** Reductions of 0.25 and 0.23 standard deviations on the Impact of Event Scale. This means fewer intrusive thoughts about cancer and less effortful avoidance of cancer-related thoughts — about a 2–3 point reduction on a 0–75 scale.

**Benefit-finding and positive affect:** Increases of 0.27 standard deviations each. This means participants reported slightly more ability to find meaning or silver linings in their cancer experience, and slightly more frequent positive emotions.

**Important context:** The effects on perceived stress and overall mood disturbance were zero — CBSM did not change how stressed people felt overall, nor did it change their general mood state. The benefits were specific to relaxation, positive emotions, and reductions in negative thoughts and biological stress markers, not to global stress perception.

**What the authors acknowledge:**

Only 1 of 18 RCTs reported adequate allocation concealment, raising concerns about selection bias

None of the trials could blind participants or therapists due to the nature of the intervention

Only 5 of 18 RCTs used intention-to-treat analysis, which may overestimate effects

High heterogeneity for anxiety and depression outcomes suggests inconsistent effects across studies

Most studies conducted in the United States, limiting generalizability

Only 2 studies used web-based delivery; most used face-to-face group format

**What a critical reader would note:**

**Publication bias:** The authors did not formally test for publication bias (e.g., funnel plot asymmetry), despite including 18 studies. Null results may be underrepresented.

**Small number of studies per outcome:** Most analyses were based on only 3–4 RCTs, reducing precision and reliability

**Short follow-up:** Most studies measured outcomes immediately post-intervention (10 weeks). Long-term durability is unknown.

**Self-report bias:** Most outcomes were self-reported questionnaires, which are subject to demand characteristics and social desirability bias

**Active control issue:** The control conditions (1-day seminar, wait-list, standard care) are weak comparators. CBSM may not outperform an active psychological intervention of equal duration and attention.

**Dose-response unknown:** Studies used varying session lengths (5–20 weeks) and formats (group vs. web), but no analysis examined whether longer interventions produced larger effects

**No blinding of outcome assessment:** While 10 studies reported blinded outcome assessment, the meta-analysis did not separately analyze blinded vs. unblinded studies to check for bias

**Commercial funding:** The study was supported by the National Natural Science Foundation of China; no industry funding was reported, but primary studies may have had undisclosed conflicts

**Population homogeneity:** All participants were women; results may not generalize to men with breast cancer or other cancers

**No active treatment comparison:** CBSM was not compared to other evidence-based psychological interventions (e.g., mindfulness-based stress reduction, cognitive-behavioral therapy for insomnia), so relative efficacy is unknown

For someone running their own n=1 experiment to test whether CBSM improves their stress, mood, or well-being:

### What to test (specific intervention and dose)

**Core protocol:** A 10-week program with weekly 2-hour sessions combining:

- 60 minutes of cognitive-behavioral skills training (cognitive reframing, coping skills, assertiveness, social support building)

- 30 minutes of relaxation training (progressive muscle relaxation, guided imagery, deep breathing)

- 30 minutes of group discussion and practice

**Self-administered version:** Use a structured workbook (e.g., the Coping With Cancer Workbook used in 2 of the included studies) with 10 chapters covering the same content, completed over 10 weeks

**Minimum dose:** 5 weeks of weekly sessions (the shortest intervention tested) showed some benefits, but 10 weeks was the most common and effective duration

**Daily practice:** 15–20 minutes of relaxation practice (progressive muscle relaxation or guided imagery) on days between sessions

### Minimum meaningful duration

**10 weeks** is the evidence-based minimum for a full trial

**5 weeks** may produce detectable changes in some outcomes (relaxation, positive affect)

**Daily relaxation practice** should begin immediately and continue throughout

**Measure at baseline, week 5, and week 10** to track trajectory

### What to measure (specific metrics)

**Primary outcome:** Perceived Stress Scale (PSS-10) — free, validated, 10-item questionnaire. Score range 0–40, higher = more stress. A positive result would be a reduction of 3–5 points.

**Secondary outcomes:**

- **Anxiety