JNCI：高脂饮食增加乳腺癌患者死亡率

　　饮食中所含有的脂肪是雌激素的来源之一，这可能会导致乳腺癌患者的生存期缩短。来自加拿大奥克兰研究中心的Candyce H. Kroenke等进行了相关研究，以评估在确诊为乳腺癌的患者中，高脂饮食摄入和低脂饮食摄入对乳腺癌的复发率和死亡率的影响，他们的研究结果发表在JNCI 3月的在线期刊上。

　　研究者共纳入了1893名女性，这些女性患者来自于“确诊为肿瘤后的生活的流行病学研究”，这些女性在1997年至2000年之间被诊断为早期侵袭性乳腺癌，并且她们在确诊后完成了Fred Hutchinson肿瘤研究中心食物频率问卷。在对上述乳腺癌患者进行了为期11.8年（中位随访时间）的随访后，共有349名患者出现了复发，另有372名患者死亡，其中189人死于乳腺癌。研究者采用延迟进入Cox风险比例回归模型评估了患者在入组时累积平均脂肪摄入，与随访5-6年后的平均脂肪摄入与其预后的关系。所有的统计检验都在双侧进行。

　　研究结果指出，在调整后的多变量分析中，总体饮食脂肪摄入与乳腺癌患者特异性的结局不相关，但是研究者发现饮食中的总体脂肪摄入的确与总体死亡率呈正相关。研究者没有发现低脂饮食摄入与乳腺癌的复发和死亡之间存在联系。然而，高脂饮食摄入的确与乳腺癌患者的临床结局呈正相关。与参考人群相比（脂肪摄入在0-0.5份/天），高脂饮食摄入（脂肪摄入在0.5-1.0份/天）的乳腺癌患者的死亡率更高，风险比为1.20, 95%可信区间为0.82-1.77，而在脂肪摄入在1.0份/天及以上的乳腺癌患者中，风险比为1.49，95%可信区间为1.00-2.24，并且她们的总体死亡率也更高，差异具有显著统计学意义，研究者也注意到高脂饮食摄入和乳腺癌复发呈正相关，但是差异未达到统计学显著意义。并且，研究者指出，无论患者摄入何种饮食，只要其脂肪含量高，那么她们复发和死亡的风险就相应增高。

　　研究结果指出，在确诊为乳腺癌的患者中，高脂饮食摄入会增加她们的死亡率，但是低脂饮食摄入却不能降低其死亡率。

与乳腺癌相关的拓展阅读：

• NCCN 2013：乳腺癌临床实践指南（2013.V1）
• JNCI：Ran表达或影响乳腺癌和肺癌患者的生存期
• J Clin Oncol：拉帕替尼一线解救提高乳腺癌生存
• NEJM: 乳腺癌放疗增加缺血性心脏病风险
• Lancet Oncol：乳腺癌腋窝淋巴结可不清扫？
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High- and Low-Fat Dairy Intake, Recurrence, and Mortality After Breast Cancer Diagnosis

Background 

Dietary fat in dairy is a source of estrogenic hormones and may be related to worse breast cancer survival. We evaluated associations between high- and low-fat dairy intake, recurrence, and mortality after breast cancer diagnosis.

Methods 

We included 1893 women from the Life After Cancer Epidemiology study diagnosed with early-stage invasive breast cancer from 1997 to 2000, who completed the Fred Hutchinson Cancer Research Center Food Frequency Questionnaire after diagnosis. A total of 349 women had a recurrence and 372 died during a median follow-up of 11.8 years, with 189 deaths from breast cancer. We used delayed entry Cox proportional hazards regression to evaluate associations between categories of the cumulative average of dairy fat at baseline and at follow-up 5 to 6 years later and subsequent outcomes. Tests of statistical significance were two-sided.

Results 

In multivariable-adjusted analyses, overall dairy intake was unrelated to breast cancer–specific outcomes, although it was positively related to overall mortality. Low-fat dairy intake was unrelated to recurrence or survival. However, high-fat dairy intake was positively associated with outcomes. Compared with the reference (0 to <0.5 servings/day), those consuming larger amounts of high-fat dairy had higher breast cancer mortality (0.5 to <1.0 servings/day: hazard ratio [HR] = 1.20, 95% confidence interval [CI] = 0.82 to 1.77; and ≥1.0 servings/day: HR = 1.49, 95% CI = 1.00 to 2.24, P trend = .05), higher all-cause mortality (P trend < .001), and higher non–breast cancer mortality (P trend = .007); the relationship with breast cancer recurrence was positive but not statistically significant. The higher risk appeared consistent across different types of high-fat dairy products.

Conclusions 

Intake of high-fat dairy, but not low-fat dairy, was related to a higher risk of mortality after breast cancer diagnosis.