Background: Obesity is a consideration in the pharmacologic intervention for estrogen receptor (ER) positive (ER+) breast cancer risk. Body mass index (BMI) and waist/hip ratio (WHR) have demonstrated different effects on breast cancer risk in relation to estrogen receptor (ER) status, but the results have been inconsistent. Furthermore, the situation in Chinese women remains unclear.
Materials and methods: We conducted a case-control study including 1,439 breast cancer cases in Northern and Eastern China. Both ER and progesterone receptor (PR) statuses were available for 1,316 cases. Associations between body size-related factors and breast cancer risk defined by receptor status were assessed by multiple polytomous unconditional logistic regression analysis.
Results: Body mass index and WHR were positively associated with overall breast cancer risk. Body mass index was positively associated with both ER+/PR positive (PR+) and ER negative (ER-)/PR negative(PR-) subtype risks, although only significantly for ER+/PR+ subtype. Waist-hip ratio was only positively correlated with ER-/PR- subtype risk, although independent of BMI. Body mass index was positively associated with risk of ER+/PR+ and ER-/PR- subtypes in premenopausal women, whereas WHR was inversely correlated with ER+/PR- and positively with ER-/PR- subtype risks. Among postmenopausal women, WHR >0.85 was associated with increased risk of ER-/PR- subtype.
Conclusion: Both general and central obesity contribute to breast cancer risk, with different effects on specific subtypes. General obesity, indicated by BMI, is more strongly associated with ER+/PR+ subtype, especially among premenopausal women, whereas central obesity, indicated by WHR, is more specific for ER-/PR- subtype, independent of menopausal status. These results suggest that different chemoprevention strategies may be appropriate in selected individuals.
Implications for practice: The results of this study suggest that general and central obesity may play different roles in different breast cancer subtypes, supporting the hypothesis that obesity affects breast carcinogenesis via complex molecular interconnections, beyond the impact of estrogens. The results also imply that different chemoprevention strategies may be appropriate for selected individuals, highlighting the need to be particularly aware of women with a high waist/hip ratio but normal body mass index. Given the lack of any proven pharmacologic intervention for estrogen receptor negative breast cancer, stricter weight-control measures may be advised in these individuals.
摘要
背景. 在对雌激素受体（ER）阳性（ER+）乳腺癌风险进行药理学干预时, 肥胖是一个考虑因素。研究证实, 体质指数（BMI）和腰围/臀围比值（WHR）对雌激素受体（ER）状态相关乳腺癌风险的影响不同, 但研究结果并不一致。此外, 尚不清楚BMI和WHR在中国女性中的情况。
材料与方法. 我们开展了一项病例对照研究, 研究中纳入了华北和华东地区的1 439例乳腺癌病例。研究中获得了1 316例病例的ER和孕激素受体（PR）状态。通过多元非条件逻辑回归分析评估了体型相关因素与通过受体状态确定的乳腺癌风险之间的相关性。
结果. 体质指数和WHR与总体乳腺癌风险呈正相关。体质指数与ER+/PR阳性（+）和ER阴性（ER–）/PR阴性（PR–）亚型风险呈正相关, 但仅与ER+/PR+亚型风险显著相关。虽然与BMI无关, 但腰围/臀围比值仅与ER–/PR–亚型风险呈正相关。在绝经前女性中, 体质指数与ER+/PR+和ER–/PR–亚型风险呈正相关, 但WHR与ER+/PR–亚型风险呈负相关, 且与ER–/PR–亚型风险呈正相关。在绝经后女性中, WHR >0.85与ER–/PR–亚型风险升高相关。
结论. 全身性和躯干性肥胖均导致乳腺癌风险升高, 但对特定亚型的影响不同。通过BMI确定的全身性肥胖与ER+/PR+亚型风险的相关性更强, 尤其是在绝经前女性中, 而通过WHR确定的躯干性肥胖与ER–/PR–亚型风险的相关性更强并且与月经状态无关。这些结果表明, 特定个体中适用的化学预防策略可能不同。
对临床实践的启示：本研究的结果表明, 在不同的乳腺癌亚型中全身性肥胖和躯干性肥胖的作用可能不同, 这支持除雌激素的影响外, 肥胖通过复杂的分子互连影响乳腺癌形成的假设。研究结果还表明, 特定个体中适用的化学预防策略可能不同, 进一步说明需尤其注意腰围/臀围比值较大但体质指数正常的女性。由于雌激素受体阴性乳腺癌缺乏任何经证实的药理学干预, 可能需对这些个体采取更加严格的体重控制措施。
Keywords: Body mass index; Breast neoplasms; Estrogen receptors; Progesterone receptors; Waist/hip ratio.
© 2017 The Authors The Oncologist published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.