Faculty of Medicine, University of New South Wales, Sydney, Australia.
Concord Repatriation General Hospital, Sydney, Australia.
Cochrane Database Syst Rev. 2020 Dec 11;12(12):CD012110. doi: 10.1002/14651858.CD012110.pub2.
Studies suggest that overweight and obese breast cancer survivors are at increased risk of cancer recurrence and have higher all-cause mortality. Obesity has an impact on breast cancer survivor's quality of life (QOL) and increases the risk of longer-term morbidities such as type 2 diabetes mellitus and cardiovascular disease. Many cancer guidelines recommend survivors maintain a healthy weight but there is a lack of evidence regarding which weight loss method to recommend.
To assess the effects of different body weight loss approaches in breast cancer survivors who are overweight or obese (body mass index (BMI) ≥ 25 kg/m).
We carried out a search in the Cochrane Breast Cancer Group's (CBCG's) Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 6), MEDLINE (2012 to June 2019), Embase (2015 to June 2019), the World Health Organisation International Clinical Trials Registry Platform (WHO ICTRP) and Clinicaltrials.gov on 17 June 2019. We also searched Mainland Chinese academic literature databases (CNKI), VIP, Wan Fang Data and SinoMed on 25 June 2019. We screened references in relevant manuscripts.
We included randomised controlled trials (RCTs), quasi-RCTs and randomised cross-over trials evaluating body weight management for overweight and obese breast cancer survivors (BMI ≥ 25 kg/m). The aim of the intervention had to be weight loss.
Two review authors independently performed data extraction and assessed risk of bias for the included studies, and applied the quality of the evidence using the GRADE approach. Dichotomous outcomes were analysed as proportions using the risk ratio (RR) as the measure of effect. Continuous data were analysed as means with the measure of effect being expressed as the mean differences (MDs) between treatment groups in change from baseline values with 95% confidence intervals (CIs), when all studies reported exactly the same outcomes on the same scale. If similar outcomes were reported on different scales the standardised mean difference (SMD) was used as the measure of effect. Quality of life data and relevant biomarkers were extracted where available.
We included a total of 20 studies (containing 23 intervention-comparisons) and analysed 2028 randomised women. Participants in the experimental groups received weight loss interventions using the core element of dietary changes, either in isolation or in combination with other core elements such as 'diet and exercise', 'diet and psychosocial support' or 'diet, exercise and psychosocial support'. Participants in the controls groups either received usual care, written materials or placebo, or wait-list controls. The duration of interventions ranged from 0.5 months to 24 months. The duration of follow-up ranged from three months to 36 months. There were no time-to-event data available for overall survival, breast cancer recurrence and disease-free survival. There was a relatively small amount of data available for breast cancer recurrence (281 participants from 4 intervention-comparisons with 14 recurrence events; RR 1.95, 95% CI 0.68 to 5.60; low-quality evidence) and the analysis was likely underpowered. Overall, we found low-quality evidence that weight loss interventions for overweight and obese breast cancer survivors resulted in a reduction in body weight (MD: -2.25 kg, 95% CI: -3.19 to -1.3 kg; 21 intervention-comparisons; 1751 women), body mass index (BMI) (MD: -1.08 kg/m, 95% CI: -1.61 to -0.56 kg/m; 17 intervention-comparisons; 1353 women), and waist circumference (MD:-1.73 cm, 95% CI: -3.17 to -0.29 cm; 13 intervention-comparisons; 1193 women), and improved overall quality of life (SMD: 0.74; 95% CI: 0.20 to 1.29; 10 intervention-comparisons; 867 women). No increase was seen in adverse events for women in the intervention groups compared to controls (RR 0.94, 95% CI: 0.76 to 1.17; 4 intervention-comparisons; 394 women; high-quality evidence). Subgroup analyses revealed that decreases in body weight, BMI and waist circumference were present in women regardless of their ethnicity and menopausal status. Multimodal weight loss interventions (which referred to 'diet, exercise and psychosocial support') appeared to result in greater reductions in body weight (MD: -2.88 kg, 95% CI: -3.98 to -1.77 kg; 13 intervention-comparisons; 1526 participants), BMI (MD: -1.44 kg/m, 95% CI: -2.16 to -0.72 kg/m; 11 studies; 1187 participants) and waist circumference (MD:-1.66 cm, 95% CI: -3.49 to -0.16 cm; 8 intervention-comparisons; 1021 participants) compared to dietary change alone, however the evidence was low quality.
AUTHORS' CONCLUSIONS: Weight loss interventions, particularly multimodal interventions (incorporating diet, exercise and psychosocial support), in overweight or obese breast cancer survivors appear to result in decreases in body weight, BMI and waist circumference and improvement in overall quality of life. There was no increase in adverse events. There is a lack of data to determine the impact of weight loss interventions on survival or breast cancer recurrence. This review is based on studies with marked heterogeneity regarding weight loss interventions. Due to the methods used in included studies, there was a high risk of bias regarding blinding of participants and assessors. Further research is required to determine the optimal weight loss intervention and assess the impact of weight loss on survival outcomes. Long-term follow-up in weight loss intervention studies is required to determine if weight changes are sustained beyond the intervention periods.
研究表明，超重和肥胖的乳腺癌幸存者复发风险增加，全因死亡率更高。肥胖会影响乳腺癌幸存者的生活质量（QOL），并增加 2 型糖尿病和心血管疾病等长期并发症的风险。许多癌症指南建议幸存者保持健康的体重，但对于推荐哪种减肥方法，证据不足。
评估超重或肥胖（BMI≥25kg/m²）乳腺癌幸存者采用不同体重减轻方法的效果。
我们在 Cochrane 乳腺癌协作组（CBCG）的专题目录、Cochrane 对照试验中心注册库（CENTRAL，第 6 期）、MEDLINE（2012 年至 2019 年 6 月）、Embase（2015 年至 2019 年 6 月）、世界卫生组织国际临床试验注册平台（WHO ICTRP）和 Clinicaltrials.gov 上进行了检索，并于 2019 年 6 月 17 日对中国内地学术文献数据库（CNKI）、VIP、万方数据和中国生物医学文献数据库（SinoMed）进行了检索。我们还对相关文献中的参考文献进行了筛选。
我们纳入了随机对照试验（RCT）、半随机对照试验和随机交叉试验，评估了超重和肥胖乳腺癌幸存者（BMI≥25kg/m²）的体重管理。干预措施的目的必须是减肥。
两名综述作者独立提取数据并评估纳入研究的偏倚风险，并使用 GRADE 方法评估证据质量。二分类结局采用风险比（RR）作为效应测量指标进行分析。连续数据采用均数表示，治疗组间变化的效应测量指标为基线值的均值差异（MD），当所有研究均以相同的标度报告完全相同的结局时采用该指标。如果以不同的标度报告类似的结局，则采用标准化均数差（SMD）作为效应测量指标。如有可用的生存质量数据和相关生物标志物，则予以提取。
我们共纳入了 20 项研究（包含 23 项干预比较），共分析了 2028 名随机女性。实验组的参与者接受了以饮食改变为核心要素的减肥干预，这些干预措施单独或与其他核心要素（如“饮食和运动”、“饮食和心理社会支持”或“饮食、运动和心理社会支持”）结合使用。对照组的参与者接受了常规护理、书面材料或安慰剂，或等待名单对照。干预的持续时间从 0.5 个月到 24 个月不等。随访时间从 3 个月到 36 个月不等。没有关于总生存、乳腺癌复发和无病生存的时间到事件数据。关于乳腺癌复发的可用数据较少（4 项干预比较，281 名参与者，14 例复发事件；RR 1.95，95% CI：0.68 至 5.60；低质量证据），分析可能存在偏倚。总体而言，我们发现低质量证据表明，超重和肥胖乳腺癌幸存者的减肥干预措施可降低体重（MD：-2.25kg，95% CI：-3.19 至-1.30kg；21 项干预比较；1751 名女性）、体重指数（BMI）（MD：-1.08kg/m，95% CI：-1.61 至-0.56kg/m；17 项干预比较；1353 名女性）和腰围（MD：-1.73cm，95% CI：-3.17 至-0.29cm；13 项干预比较；1193 名女性），并改善整体生活质量（SMD：0.74，95% CI：0.20 至 1.29；10 项干预比较；867 名女性）。与对照组相比，干预组女性的不良事件发生率没有增加（RR 0.94，95% CI：0.76 至 1.17；4 项干预比较；394 名女性；高质量证据）。亚组分析显示，无论种族和绝经状态如何，女性的体重、BMI 和腰围均有下降。多模式减肥干预（指“饮食、运动和心理社会支持”）似乎能更显著地降低体重（MD：-2.88kg，95% CI：-3.98 至-1.77kg；13 项干预比较；1526 名参与者）、BMI（MD：-1.44kg/m，95% CI：-2.16 至-0.72kg/m；11 项研究；1187 名参与者）和腰围（MD：-1.66cm，95% CI：-3.49 至-0.16cm；8 项干预比较；1021 名参与者），但证据质量较低。
超重或肥胖的乳腺癌幸存者的减肥干预措施，特别是多模式干预措施（包括饮食、运动和心理社会支持），似乎能降低体重、BMI 和腰围，改善整体生活质量。不良事件发生率没有增加。目前缺乏数据来确定减肥干预对生存或乳腺癌复发的影响。本综述基于减肥干预措施存在显著异质性的研究。由于纳入研究中使用的方法，参与者和评估者的偏倚风险很高。需要进一步的研究来确定最佳的减肥干预措施，并评估减肥对生存结果的影响。减肥干预研究需要长期随访，以确定体重变化是否能持续到干预期之外。
