Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., M4-B402, P.O. Box 19024, Seattle, WA 98109-1024, USA.
Cancer Epidemiol Biomarkers Prev. 2011 Mar;20(3):454-63. doi: 10.1158/1055-9965.EPI-10-0974. Epub 2011 Mar 1.
Triple-negative breast cancer, characterized by a lack of hormone receptor and HER2 expression, is associated with a particularly poor prognosis. Focusing on potentially modifiable breast cancer risk factors, we examined the relationship between body size, physical activity, and triple-negative disease risk.
Using data from 155,723 women enrolled in the Women's Health Initiative (median follow-up, 7.9 years), we assessed associations between baseline body mass index (BMI), BMI in earlier adulthood, waist and hip circumference, waist-hip ratio, recreational physical activity, and risk of triple-negative (n=307) and estrogen receptor-positive (ER+, n=2,610) breast cancers.
Women in the highest versus lowest BMI quartile had 1.35-fold (95% CI, 0.92-1.99) and 1.39-fold (95% CI, 1.22-1.58) increased risks of triple-negative and ER+ breast cancers, respectively. Waist and hip circumferences were positively associated with risk of ER+ breast cancer (Ptrend=0.01 for both measures) but were not associated with triple-negative breast cancer. Compared with women who reported no recreational physical activity, women in the highest activity tertile had similarly lower risks of triple-negative and ER+ breast cancers (HR=0.77; 95% CI, 0.51-1.13; and HR=0.85; 95% CI, 0.74-0.98, respectively).
Despite biological and clinical differences, triple-negative and ER+ breast cancers are similarly associated with BMI and recreational physical activity in postmenopausal women. The biological mechanisms underlying these similarities are uncertain and these modest associations require further investigation.
If confirmed, these results suggest potential ways postmenopausal women might modify their risk of both ER+ and triple-negative breast cancers.
三阴性乳腺癌的特点是缺乏激素受体和 HER2 表达，与预后特别差有关。本研究关注潜在可改变的乳腺癌危险因素，探讨了体型和身体活动与三阴性疾病风险之间的关系。
本研究使用了参加妇女健康倡议的 155723 名女性的数据（中位随访时间为 7.9 年），评估了基线体重指数（BMI）、成年早期 BMI、腰围和臀围、腰臀比、休闲身体活动与三阴性（n=307）和雌激素受体阳性（ER+，n=2610）乳腺癌风险之间的关系。
与最低 BMI 四分位数组相比，最高 BMI 四分位数组的三阴性和 ER+乳腺癌风险分别增加 1.35 倍（95%CI，0.92-1.99）和 1.39 倍（95%CI，1.22-1.58）。腰围和臀围与 ER+乳腺癌风险呈正相关（P 趋势值均<0.01），但与三阴性乳腺癌无关。与不报告休闲身体活动的女性相比，最高活动三分位组的三阴性和 ER+乳腺癌风险也显著降低（HR=0.77；95%CI，0.51-1.13；HR=0.85；95%CI，0.74-0.98）。
尽管三阴性和 ER+乳腺癌具有生物学和临床差异，但在绝经后妇女中，它们与 BMI 和休闲身体活动均相关。这些相似性的生物学机制尚不清楚，需要进一步研究这些适度的关联。
如果得到证实，这些结果表明绝经后女性可能有潜在的方法来改变她们患 ER+和三阴性乳腺癌的风险。
