Effect of physical exercise on postoperative shoulder mobility and upper limb function in patients with breast cancer: a systematic review and meta-analysis

Background: The shoulder pain and reduced range of motion caused by breast cancer seriously affect the quality of life of women. Such persistent impairments can escalate into chronic pain, diminished muscle strength, lymphedema, and compromised cardiorespiratory health potentially culminating in permanent disability. This systematic review aims to evaluate how physical exercise impacts shoulder mobility and upper limb function in breast cancer patients post-surgery, examining various aspects of exercise such as type, intensity, duration, frequency, and intervention timing to determine the influence on outcomes. Methods: A comprehensive search was conducted across seven databases up to April 16, 2024. Two reviewers independently assessed randomized controlled trials (RCTs) focusing on the effects of physical exercise on postoperative outcomes in breast cancer patients. Quality was assessed using the Cochrane risk of bias tool, with meta-analyses and publication bias tests performed via RevMan5.4, and evidence quality evaluated using GRADEPro. Effect sizes were calculated using standardized mean differences (SMDs) with 95% confidence intervals (CIs). Results: Twenty studies (25 RCTs involving 2,171 patients) were included for both the systematic review and the meta-analysis. Meta-analysis confirmed that physical exercise significantly enhanced shoulder flexion (SMD =0.59; 95% CI: 0.32, 0.86; P<0.001) and abduction (SMD =1.01; 95% CI: 0.43, 1.60; P<0.001) in postoperative patients, and improved upper limb function (SMD =0.87; 95% CI: 0.48, 1.26; P<0.001). Subgroup analyses indicated that comprehensive exercise, particularly when performed <= 3 times a week or over 8-12 weeks, was most effective for improving shoulder flexion, while shorter durations (<8 weeks) and similar frequencies were optimal for abduction. Resistance exercises, especially when started early (<2 weeks post-surgery), showed significant benefits for upper limb function. Conclusions: The included studies were of moderate to high quality, though some lacked detailed reporting on blinding or allocation concealment. Analysis suggests that the timing of intervention initiation, along with exercise type and frequency, may contribute to observed variations in outcomes. Evidence quality assessments did not reveal significant issues with indirectness or imprecision, and no significant publication bias was detected. Given the low heterogeneity and absence of significant downgrade factors, intermediate evidence quality was assigned for upper limb function and shoulder abduction, with high quality for shoulder flexion. Physical exercise is notably effective in enhancing both upper limb function and shoulder mobility in breast cancer patients, with the timing and frequency of exercise interventions influencing these improvements. This provides valuable evidence for clinical rehabilitation strategies.