一项纳入70个临床试验包含80000名早期乳腺癌妇女的研究发现，只有在20000名绝经前ER+阳性患者中，肥胖与乳腺癌相关死亡增加34%具有相关性。肥胖对绝经后ER阳性，或ER阴性女性几乎没有影响。
主要研究者，牛津大学的Hongchao Pan博士说到：肥胖一般只会增加绝经后妇女血液中的雌激素水平，所以我们非常吃惊看到肥胖只给绝经前女性带来不利的影响。这意味着我们还不明白肥胖影响预后的主要生物学机制。
早期乳腺癌试验协作组（EBCTCG）研究比较了在同一临床试验接受同样治疗的女性的记录。根据BMI定义正常体重、超重和肥胖（20-25,25-30，≥30kg/m2）为了评估BMI对预后的独立影响，研究人员调整了肿瘤特征，例如大小、淋巴结转移，以及治疗中的任何差异。
对于20000名绝经前ER阳性患者，肥胖女性的乳腺癌死亡率比正常体重女性升高1/3，也就是说，将10年死亡率风险15%变成了10年死亡率风险20%。
与此相反，肥胖对40000名绝经后ER阳性妇女和20000名ER阴性女性的结局影响不大。
该研究由英国癌症研究中心，MRC和英国心脏基金会赞助。
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会议专题》》》2014年ASCO年会专题报道
英文摘要
Title: Effect of obesity in premenopausal ER+ early breast cancer: EΒCΤCG data on 80,000 patients in 70 trials.（Abstract #503）
Breast Cancer HER2/ER Oral Abstract Session
Authors: Hongchao Pan, Richard G. Gray, on behalf of the Early Breast Cancer Trialists' Collaborative Group; Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom; University of Oxford, Oxford, United Kingdom
Background: Obesity (body mass index [BMI] ≥30 kg/m2) is reportedly associated with worse prognosis in early breast cancer. But, this association could depend strongly on estrogen receptor (ER) positivity and ovarian activity (or young age).
Methods: Through EBCTCG, anonymised information on each individual with early breast cancer in any trial is requested periodically, including BMI (at randomisation), ER status, menopausal status, age, treatment, recurrence and death. The global Steering Committee has requested analyses of the independent effects of BMI on outcome. Results are provided for 80,000 patients (in 70 trials) who had all these data items; most also had data on tumour diameter and nodal status. Mean follow-up was 8 woman-years. Cox regression (stratified for trial and treatment, and adjusted for age) assesses the relevance of BMI to mortality with recurrence (as a surrogate for the relevance of BMI to breast cancer mortality). Few had BMI <20 kg/m2; the standard WHO cut-points define overweight (25-30 kg/m2).
Results: In 20,000 women with ER-poor disease there was little association of BMI with breast cancer mortality, and none after adjustment for tumour diameter and nodal status. In 60,000 with ER+ disease, BMI was positively associated with breast cancer mortality in pre/peri- and in post-menopausal women (each 2P<0.00001). But, after adjustment for tumour characteristics the association remained clearly significant only in 20,000 pre/peri-menopausal women with ER+ disease (breast cancer mortality rate ratio comparing BMI ≥30 versus BMI 20-25 kg/m2 [RR] = 1.34, 95%CI 1.22-1.47, 2P<0.00001, with a steady trend between BMI <25, 25-30, 30-35 and ≥35 kg/m2); little association remained in 40,000 post-menopausal women with ER+ disease (RR=1.06, 95%CI 0.99-1.14, 2P=0.12; heterogeneity between RRs 2P<0.0001). In analyses of ER+ disease subdivided by age (instead of menopausal status), obesity appeared importantly relevant only to age about 55 years. Findings were not materially altered by excluding the first 5 years of follow-up.
Conclusions: In women with early breast cancer, obesity appears strongly independently related to breast cancer mortality only in pre/peri-menopausal ER+ disease.
Disclosures: Nothing to disclose.
Research Funding Source: UK Medical Research Counsel, Cancer Research UK, British Heart Foundation
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