Table 2.
Included systematic reviews and meta-analyses methodology and results.
| Study | Objectives & Population | Procedure under evaluation (N)/Comparator(s)/Type and number of studies | Primary outcomes | Meta-Analysis: results, comparison values, and significance | Conclusions |
|---|---|---|---|---|---|
| Boing, 2020 (43) |
Investigate PE effect on physical outcomes in BC women receiving any modality of hormone therapy. | Effect of PE on physical outcomes (N=368)/ PE vs usual care; Unsupervised PE vs supervised PE/ 3 RCTs; 2 single-arm pilot studies. |
Cardiorespiratory fitness (VO2max), muscle strength, pain, body fat percentage, bone mineral density. | Cardiorespiratory fitness: SMD = 0.37; p=0.005. Grip strength: SMD = 0.298; p=0.091. |
Three of the five trials demonstrated significant effects separately in improving VO2max. This trend was reflected in the meta-analysis. |
| Abdin, 2019 (44) |
Evaluate PE and specifically consider the effects of different types of exercise and intervention (group vs individual) in adult patients with BC (invasive and in situ carcinoma). | Intervention aiming to increase PE (N=2208)/ Different types of PE interventions/ 17 RCTs. |
Self-reported levels of PE, adherence, cardiorespiratory fitness, QoL, BMI, weight, and fatigue. | Meta-analysis was not performed (due to population heterogeneity, intervention components, outcome measurements, and duration of interventions). | Individual and group interventions have positive outcomes, but some indicators highlight more benefits in group interventions. It was impossible to conclude whether there are differences in outcomes depending on the type of PE. It remains apparent that the lack of clarity of reporting and theory in intervention design is a problem. |
| Hong, 2019 (45) |
Examine PE effect on HRQoL, social function, and physical function; explore the most effective characteristics of PE (type, frequency, duration, time, and total exercise time); and determine optimal PE time for HRQoL improvement in adults diagnosed with BC. | PE intervention (aerobic, resistance, combined, yoga, and Qigong) (N= 1892 in the systematic review; N=1205 [exercise 602 and control 603])/ Not submitted to PE intervention/ 26 RCTs in the systematic review and 18 in the meta-analysis. |
QoL (general, global health, and overall QoL), SF, and PF. | Change in HRQoL: extremely (p = 0.0004) influenced by exercise intervention, with heterogeneity: Tau2 = 0.10; Chi2 = 43.68; df = 17; and I2 = 61%. “Time of session”: significantly (p = 0.041) correlated with an improved QoL. SF outcome: extremely favoured exercise, citing the SMD = 0.20, I2 = 16%, and 95% CI: 0.08 to 0.32. PF outcome: improved by exercise interventions (p < 0.00001); pooled SMD of the enhanced PF was 0.32 (0.20 to 0.44), at a 95% CI, and where the I2 was 32% after the interventions. |
PE interventions (of any type) improve HRQoL and social and physical function in women BC survivors. However, HRQoL improvement was associated with session duration (>45 min). |
| Soares Falcetta, 2018 (46) |
Disclose PE effect (with or without dietary interventions) on body composition, HRQoL, and survival in women after early-stage (I–III) BC treatment. | Studies that performed the intervention after the end of adjuvant treatment (excluding hormone therapy) were included; studies that applied the intervention after 5 years from the diagnosis were excluded. From a total of 60 studies included, only 19 RCTs with a structured or individualised PE program (N=1613; PE 835 and control 778) were assessed. |
Overall survival and disease-free survival (5 years after treatment or until the maximum follow-up study). Secondary endpoints: weight loss (kg), BMI (kg/m2), waist-hip ratio, percentage of body fat (%), and HRQoL. AEs, such as PE-induced lesions, were also considered. |
Weight reduction: mean diff -0.27 (-1.16;0.63); n=835 (experimental group) and n=787 (control group); BMI reduction: -0.36 (-0.83;0.11); n=797 (experimental group) and n=752 (control group); HRQoL (general) for different scales: SMD=0.76 (0.19-1.34); n= 421 (experimental group) and n=388 (control group). |
Heterogeneous types of intervention showed significant effects on anthropometric measures and HRQoL. Only one study had mortality as an outcome, showing PE as a protective intervention. Despite these findings, publication bias and poor methodological quality were presented. PE should be advised for BC survivors since it has no AEs and can improve anthropometric measures and QoL. |
| Singh, 2018 (47) |
Evaluate PE safety, feasibility, and effect among women with stage II+ BC. | Randomised, controlled PE trials were included, involving at least 50% of women diagnosed with stage II+ BC. From the 61 trials included in this systematic review, 60 RCTs evaluated PE safety and the risk of AEs. |
The risk of bias was assessed, and AEs severity was classified using the Common Terminology Criteria. Feasibility was evaluated by computing median (range) recruitment, withdrawal, and adherence rates. Meta-analyses were performed to evaluate PE safety and effects on health outcomes only. The influence of intervention characteristics (mode, supervision, duration, and timing) on PE outcomes were also explored. | Significant effects of PE on HRQoL, fitness, fatigue, strength, anxiety, depression, BMI, and waist circumference compared with usual care (stand mean diff range: 0.17-0.77, p<0.05). There were no differences in AEs between PE and usual care (risk difference: <0.01 ([95% CI: -0.01, 0.01], p=0.38). The median recruitment rate was 56% (1%-96%), the withdrawal rate was 10% (0%-41%), and the adherence rate was 82% (44%-99%). Safety and feasibility outcomes were similar, irrespective of PE mode, supervision, duration, or timing. |
The findings support PE safety, feasibility, and effects for those with stage II+ BC, suggesting that national and international exercise guidelines appear generalisable to women with local, regional, and distant BC. |
| Lahart, 2018 (6) |
Assess the effects of PE interventions after adjuvant therapy for women with BC. | Randomised and quasi-randomised trials comparing PE interventions vs control (e.g., usual or standard care, no PE, no exercise, attention control, placebo) after adjuvant therapy (i.e., after completion of chemotherapy and/or radiation therapy, but not hormone therapy) in women with BC. The study included 63 trials that randomised 5761 women to a physical activity intervention (n = 3239) or a control (n = 2524). |
Outcomes of HRQoL, PE, and cardiorespiratory fitness. The overall effect size with 95% CIs was calculated for each outcome; GRADE was used to assess the quality of evidence for the most critical outcomes. GRADE working group grades of evidence: High quality: Further research is unlikely to change the confidence in the effect estimate. Moderate quality: Further research is likely to impact the confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to impact the confidence in the estimate of effect and is likely to change the estimate. Very low quality: There is high uncertainty about the estimate. |
Changes from baseline to the end of intervention after a median follow-up of 12 weeks: 1 – HRQoL: 14 studies were assessed, comprising 1459 participants. The illustrative comparative risk (95% CI) was 0.78 standard deviations higher (0.39 to 1.17 higher) in the physical activity group and -2.40 to 1.25 standard deviation units in the control group. Quality of evidence (GRADE): low. 2 – Emotional function/mental health: 15 studies were assessed, comprising 1579 participants. The illustrative comparative risk (95% CI) was 0.31 standard deviations higher (0.09 to 0.53 higher) in the physical activity group and -0.39 to 3.47 standard deviation units in the control group. Quality of evidence (GRADE): low. 3 – Perceived physical function: 13 studies were assessed, comprising 1433 participants. The illustrative comparative risk (95% CI) was 0.60 standard deviations higher (0.23 to 0.97 higher) in the physical activity group and -1.34 to 1.66 standard deviation units in the control group. Quality of evidence (GRADE): moderate. 4 – Anxiety change: 4 studies were assessed, comprising 235 participants. The illustrative comparative risk (95% CI) was 0.37 standard deviations lower (0.63 to 0.12 lower) in the physical activity group and -1.44 to 0.73 standard deviation units in the control group. Quality of evidence (GRADE): low. 5 – Depression change: 7 studies were assessed, comprising 816 participants. The illustrative comparative risk (95% CI) was 0.34 standard deviations lower (0.63 to 0.05 lower) in the physical activity group and -1.51 to 1.83 standard deviation units in the control group. Quality of evidence (GRADE): low. 6 – Fatigue change: 13 studies were assessed, comprising 1289 participants. The illustrative comparative risk (95% CI) was 0.30 standard deviations lower (0.61 to 0 lower) in the physical activity group and -1.81 to 1.83 standard deviation units in the control group. Quality of evidence (GRADE): low. 7 – Cardiorespiratory change: 9 studies were assessed, comprising 863 participants. The illustrative comparative risk (95% CI) was 0.83 standard deviations higher (0.40 to 1.27 higher) in the physical activity group and -1.45 to 2.38 standard deviation units in the control group. Quality of evidence (GRADE): very low. |
There were no conclusions regarding BC-related and all-cause mortality or BC recurrence. However, PE interventions may have small-to-moderate beneficial effects on HRQoL, emotional or perceived physical and social function, anxiety, cardiorespiratory fitness, and self-reported and objectively measured physical activity. The positive results reported in the current review must be interpreted cautiously owing to the very low-to-moderate quality of evidence, heterogeneity of interventions and outcome measures, imprecision of some estimates, and risk of bias in many trials. Future studies with a low risk of bias are required to determine the optimal combination of physical activity modes, frequencies, intensities, and durations needed to improve specific outcomes among women who have undergone adjuvant therapy. |
| Zhang, 2019 (48) |
Assess the PE effect on the HRQoL among people with BC. | Effect of PE on HRQoL compared with that of usual care for people with BC. N = 36 RCT (3914 participants) |
PE was categorised into three modes: aerobic, resistance, and a combination of aerobic and resistance. The outcome measure was the QoL. |
Meta-analysis was not performed. This Systematic review revealed that all three PE intervention modes significantly affected the QoL between groups. |
PE is a safe and effective way to improve HRQoL in BC patients. Combined training was associated with a significant improvement in HRQoL. In future research, more high-quality, multicenter trials evaluating the effect of exercise in BC patients are needed. |
| Gebruers, 2019 (49) |
Characterise PE programs and their effects on (1) physical performance outcomes, (2) experienced fatigue, and (3) HRQoL in patients during the initial treatment for BC. | N = 28 RCT (2525 participants) | The primary outcome was the PE effect on physical performance, HRQoL, and perceived fatigue. | Meta-analysis was not performed. | Most training interventions provided an improvement in physical performance and a decrease in perceived fatigue. HRQoL was the outcome variable least susceptible to improvement. |
| Kannan, 2022 (50) |
Investigate PE effect on QoL and upper quadrant pain in women with PMPS (post-mastectomy pain syndrome) | PE intervention (aerobic exercise, resistance training, aqua fitness) No PE intervention N=10 RCT (4 RCT with 451 patients to evaluate PE effect on QoL; 6 RCT with 406 patients to evaluate PE effect on upper quadrant pain) |
QoL, upper quadrant pain | Effect of PE on QoL: a statistically significant effect of the intervention on general [SMD 0.87 (95%CI: 0.36-1.37); p = 0.001], physical [SMD 0.34 (95%CI: 0.01-0.66); p = 0.044] and mental health components [SMD 0.27 (95%CI: 0.03-0.51); p = 0.027], when compared to the control condition. Effect of PE on upper quadrant pain: more significant reduction in pain severity in the intervention group than the control group [SMD -1.00 (95%CI: -1.48 to -0.52); p < 0.001) |
Meta-analysis revealed statistically significant effects of exercise compared to control in improving overall QoL and pain. Exercise is a low-cost and safe intervention and could, therefore, be considered an essential component of QoL and pain management among women with PMPS |
| Salam, 2022 (51) |
Evaluate the effects of post-diagnosis PE on depression, physical functioning, and mortality in breast cancer survivors | PE intervention (home-based/unsupervised; supervised aerobic resistance, strengthening and core exercises, yoga, gymnastics) No physical activity (i.e., a regular care group or non-physical intervention) N=26 RCT (13 studies for the effect of PE on depression, 8 for the effect of PE on physical functioning/QoL, 7 for the effect of PE on mortality; some studies were investigating both depression, physical functioning, and mortality, therefore, entered twice for the statistical analysis) |
Depression (measurements with CES-D, HADS, BDI, POMS and Greene Climacteric Scale), physical functioning/QoL (SF-36 and EORTC QLQ-C30 subscales), mortality | Effect of PE on depression (N= 689 participants in the PE group vs 480 participants in the control group): differences in the depression scores were statistically significant compared with controls (SMD -0.24, 95% CI -0.43 to -0.05, P = 0.012), with moderate statistical heterogeneity identified (P = 0.011, I2 = 54%) Effect of PE on physical functioning/QoL (N= 689 participants in the PE group vs 480 participants in the control group): statistically significant differences between the PE and control groups (SMD 0.37, 95% CI 0.03-0.72, P = 0.032), with moderate statistical heterogeneity (P = 0.01, I2 = 62%) Effect of PE on mortality (N=15,853 participants): the overall effect of physical activity was statistically significant (HR 0.63, 95% CI 0.55-0.71, p < 0.00001), with no evidence of statistical heterogeneity (p = 0.27, I2 = 15%). |
There is sufficient evidence to support the effectiveness of PE and physical activity in addressing cancer-related health outcomes, including fatigue, quality of life, physical function, anxiety, and depressive symptoms |
| Wang, 2022 (52) |
Evaluate the benefits of aquatic physical therapy as a rehabilitation strategy for women with BC |
Aquatic exercise (8 weeks) Usual care and all forms of intervention except aquatic exercise N=2 RCT (52 patients on PE-group vs 51 patients in the control group) |
Fatigue, waist circumference | Effect of aquatic PE on fatigue: statistically significant differences among groups (MD = -2.14, 95% CI: -2.82, -1.45, p<0.01), with 0% of heterogeneity. Effect of aquatic PE on waist circumference: no statistically significant differences between groups (MD = -3.49, 95% CI: -11.56, 4.58, p = 0.4) |
Aquatic physical therapy significantly relieved fatigue. However, compared with usual care, aquatic physical therapy did not improve physical index (waist circumference), which might be due to the short intervention time, which is not enough to produce a significant statistical difference |
| Ye, 2022 (53) |
Investigate the effects of Baduanjin exercise on the QoL and psychological status of postoperative patients with BC |
Baduanjin exercise No PE (i.e., a regular care group or non-physical intervention) N=7 RCT (450 participants) |
QoL (measurements with FACT-B and SF-36 scores), anxiety (measurements with SAS and SDS scales) | Effect of Baduanjin on QoL (FACT-B): Exercise-group with higher values of QoL than the control group (WMD with 95% CI = 5.70 (3.11, 8.29), P < 0.0001) Effect of Baduanjin on QoL (SF-36): PE improved QOL in the dimensions of role-physical (WMD with 95% CI = 11.49 [8.86, 14.13], P < 0.00001, I2 = 0%) and vitality (WMD with 95% CI = 8.58 [5.60, 11.56], P < 0.00001, I2 = 0%), but no statistical difference was found for physical functioning, bodily pain, social functioning, general health, and mental health (physical functioning: WMD with 95% CI = 0.97 (−1.57, 3.50), P = 0.45, I2 = 0%; bodily pain: WMD with 95% CI = 0.81 (−1.97, 3.58), P = 0.57, I2 = 0%; social functioning: WMD with 95% CI = −0.50 (−16.91, 15.90), P = 0.95, I2 = 62%; general health: WMD with 95% CI = 2.97 (−0.05, 5.99), P = 0.05, I2 = 0%; role-mental: WMD with 95% CI = 3.03 (−3.18, 9.24), P = 0.34, I2 = 5%; mental health: WMD with 95% CI = 7.47 (−1.01, 15.94), P = 0.08, I2 = 75%). Effect of Baduanjin on anxiety: depression scores for the exercise group were lower than those of the control group (WMD with 95% CI = -4.45(-5.62, -3.28), P < 0.00001). |
Results showed that Baduanjin interventions improved the QOL of postoperative patients with BC compared to those without Baduanjin. Subgroup analysis found that Baduanjin exercise improved physical function and vitality in postoperative patients with BC. In terms of anxiety and depression relief, Baduanjin exercise also had a significant effect. |
BC, Breast cancer; PE, Physical exercise; AEs, Adverse events; BMI, Body Mass Index; SMD, standardized mean difference; HRQoL, Health-Related Quality of life; RCT, randomized clinical trials; SF, social function; PF, physical function; df, degrees of freedom; HRQoL, Health-related quality of life.