前情提要
大豆食品具有抗雌激素和类雌激素的性质，是否应该建议乳腺癌女性多吃或少吃大豆食品仍然存在争议，尤其对于那些接受激素疗法治疗癌症者。
2017年3月6日，美国癌症学会官方期刊《癌症》在线发表塔夫茨大学、哥伦比亚大学、多伦多大学和西奈山医院、福克斯·蔡斯癌症中心、犹他大学、加利福尼亚癌症预防研究所、斯坦福大学的长期大样本多种族研究报告，发现乳腺癌女性大豆异黄酮饮食摄入量越高，其总死亡率越低，尤其对于激素受体阴性肿瘤和那些未接受激素疗法治疗癌症的女性。
大豆制品被认为是健康食品，但是其类似雌激素的特征，已经引起人们对乳腺癌潜在风险增加的顾虑，因为高雌激素水平有助于激素受体阳性乳腺癌细胞的生长和转移，尽管这仍然存在争议。异黄酮是大豆中的主要植物雌激素成分，实验室研究已经显示其可减缓乳腺癌细胞生长，并且东亚女性乳腺癌流行病学分析发现，异黄酮摄入量较高与死亡率较低有相关性；然而，其他研究表明，异黄酮的雌激素样效应可能降低乳腺癌激素疗法的有效性。由于这种矛盾的结果，现在仍然不确定应该鼓励还是应该避免乳腺癌患者摄入异黄酮。
本研究由国家癌症研究所资助，调查了乳腺癌家庭登记数据库6235位美国和加拿大乳腺癌女性异黄酮饮食摄入量与全部原因所致死亡之间的相关性，其中诊断乳腺癌前、后报告饮食的女性分别为5178、1664位。使用《夏威夷和洛杉矶多种族队列》制定的《食物频次问卷》评定饮食摄入量，使用Cox比例风险模型估计风险比和95%置信区间。
乳腺癌家庭登记数据库来自美国（旧金山、纽约、费城、盐湖城）、加拿大（安大略省）、澳大利亚近（墨尔本、悉尼）12000个家庭的3万多位被调查者、超过150位调查者，始于1995年。这些家庭被调查者和调查者付出的时间和精力，使该数据库成为如今独有的资源，并不断被世界各地乳腺癌研究者广泛利用，以找到预防、诊断和治疗癌症的新方法。
结果发现，中位随访113个月（约9.4年）期间，死亡1224例。异黄酮饮食摄入量最高与最低的四分之一女性相比，全部原因所致死亡率显著减少21%（每天≥1.5比＜0.3mg，风险比：0.79，95%置信区间：0.64～0.97，趋势P值：0.01）。
其中，对于激素受体阴性肿瘤、未接受激素疗法（例如他莫昔芬）的乳腺癌，摄入量较高者的死亡率分别显著减少51%、32%（风险比：0.49、0.68，95%置信区间：0.29～0.83、0.51～0.91，趋势P值：0.005、0.02）。但是，对于激素受体阳性肿瘤、接受激素疗法（例如他莫昔芬）的乳腺癌，摄入量较高者的死亡率差异均无统计学意义。交互P值均无统计学意义。
因此，在这个北美大样本多种族乳腺癌女性人群中，异黄酮饮食摄入量较高与全部原因所致死亡率较低有相关性。
对此，埃默里大学温希普癌症研究所的血液与肿瘤内科专家发表同期评论：大豆食品、异黄酮与乳腺癌。
超过20%的已知激素受体状态新乳腺癌病例为激素受体阴性，并且其生存率低于激素受体阳性病例。乳腺癌诊断后，生活方式因素能否改善生存是一个重要的问题，该研究结果表明，摄入异黄酮的患者可能生存较好。需要注意的是，该研究对象为天然存在的饮食异黄酮，而非异黄酮补充剂。尚不清楚饮食异黄酮与乳腺癌细胞如何相互作用，但是既往研究表明，饮食异黄酮存在抗氧化、抗炎、抗血管生成和其他影响肿瘤生存和生长的功能。美国是世界第一大豆生产国，并且有能力发起卫生政策改变，鼓励大豆摄入。现在有证据表明，大豆食品不仅预防乳腺癌，而且有益于乳腺癌女性，因此可以推荐女性摄入大豆食品。
Cancer. 2017 Mar 6. [Epub ahead of print]
Dietary isoflavone intake and all-cause mortality in breast cancer survivors: The Breast Cancer Family Registry.
Fang Fang Zhang, Danielle E. Haslam, Mary Beth Terry, Julia A. Knight, Irene L. Andrulis, Mary B. Daly, Saundra S. Buys, Esther M. John.
Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts; Mailman School of Public Health, Columbia University, New York, New York; Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Clinical Genetics, Fox Chase Cancer Center, Philadelphia, Pennsylvania; Huntsman Cancer Institute at the University of Utah Health Sciences Center, Salt Lake City, Utah; Cancer Prevention Institute of California, Fremont, California; Department of Health Research and Policy (Epidemiology) and Stanford Cancer Institute, Stanford University of School of Medicine, Stanford, California.
Higher dietary intake of isoflavone in women with breast cancer is associated with reduced total mortality. This reduction is largely confined to women who have estrogen receptor-negative/progesterone receptor-negative tumors and those who do not receive hormone therapy as part of cancer treatment.
BACKGROUND: Soy foods possess both antiestrogenic and estrogen-like properties. It remains controversial whether women diagnosed with breast cancer should be advised to eat more or less soy foods, especially for those who receive hormone therapies as part of cancer treatment.
METHODS: The association of dietary intake of isoflavone, the major phytoestrogen in soy, with all-cause mortality was examined in 6235 women with breast cancer enrolled in the Breast Cancer Family Registry. Dietary intake was assessed using a Food Frequency Questionnaire developed for the Hawaii-Los Angeles Multiethnic Cohort among 5178 women who reported prediagnosis diet and 1664 women who reported postdiagnosis diet. Cox proportional-hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).
RESULTS: During a median follow-up of 113 months (approximately 9.4 years), 1224 deaths were documented. A 21% decrease was observed in all-cause mortality for women who had the highest versus lowest quartile of dietary isoflavone intake (≥1.5 vs < 0.3 mg daily: HR, 0.79; 95% confidence interval CI, 0.64-0.97; Ptrend = .01). Lower mortality associated with higher intake was limited to women who had tumors that were negative for hormone receptors (HR, 0.49; 95% CI, 0.29-0.83; Ptrend = .005) and those who did not receive hormone therapy for their breast cancer (HR, 0.68; 95% CI, 0.51-0.91; Ptrend = .02). Interactions, however, did not reach statistical significance.
CONCLUSIONS: In this large, ethnically diverse cohort of women with breast cancer living in North America, a higher dietary intake of isoflavone was associated with reduced all-cause mortality.
KEYWORDS: breast cancer; breast cancer survivors; isoflavone; mortality; soy; survival
FUNDED BY: U.S. National Cancer Institute. Grant Number: UM1 CA164920
DOI: 10.1002/cncr.30615
Cancer. 2017 Mar 6. [Epub ahead of print]
Soy foods, isoflavones, and breast cancer.
Omer Kucuk.
Department of Hematology and Medical Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia.
Recent data from Asia and North America indicate that soy foods may decrease the risk of breast cancer and improve the results of treatment in patients with breast cancer. Studying soy foods and isoflavones promises to be an exceptionally fertile area for a wide range of cancer researchers.
DOI: 10.1002/cncr.30614
联系客服
