Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
J Natl Cancer Inst. 2010 Nov 17;102(22):1716-23. doi: 10.1093/jnci/djq414. Epub 2010 Oct 29.
Lobular involution, or age-related atrophy of breast lobules, is inversely associated with breast cancer risk, and mammographic breast density (MBD) is positively associated with breast cancer risk.
To evaluate whether lobular involution and MBD are independently associated with breast cancer risk in women with benign breast disease, we performed a nested cohort study among women (n = 2666) with benign breast disease diagnosed at Mayo Clinic between January 1, 1985, and December 31, 1991 and a mammogram available within 6 months of the diagnosis. Women were followed up for an average of 13.3 years to document any breast cancer incidence. Lobular involution was categorized as none, partial, or complete; parenchymal pattern was classified using the Wolfe classification as N1 (nondense), P1, P2 (ductal prominence occupying <25%, or >25% of the breast, respectively), or DY (extremely dense). Hazard ratios (HRs) and 95% confidence intervals (CIs) to assess associations of lobular involution and MBD with breast cancer risk were estimated using adjusted Cox proportional hazards model. All tests of statistical significance were two-sided.
After adjustment for MBD, having no or partial lobular involution was associated with a higher risk of breast cancer than having complete involution (none: HR of breast cancer incidence = 2.62, 95% CI = 1.39 to 4.94; partial: HR of breast cancer incidence = 1.61, 95% CI = 1.03 to 2.53; P(trend) = .002). Similarly, after adjustment for involution, having dense breasts was associated with higher risk of breast cancer than having nondense breasts (for DY: HR of breast cancer incidence = 1.67, 95% CI = 1.03 to 2.73; for P2: HR of breast cancer incidence = 1.96, 95% CI = 1.20 to 3.21; for P1: HR of breast cancer incidence = 1.23, 95% CI = 0.67 to 2.26; P(trend) = .02). Having a combination of no involution and dense breasts was associated with higher risk of breast cancer than having complete involution and nondense breasts (HR of breast cancer incidence = 4.08, 95% CI = 1.72 to 9.68; P = .006).
Lobular involution and MBD are independently associated with breast cancer incidence; combined, they are associated with an even greater risk for breast cancer.
小叶退化，或与年龄相关的乳腺小叶萎缩，与乳腺癌风险呈负相关，而乳腺密度（MBD）与乳腺癌风险呈正相关。
为了评估小叶退化和 MBD 是否与患有良性乳腺疾病的女性的乳腺癌风险独立相关，我们对 1985 年 1 月 1 日至 1991 年 12 月 31 日期间在梅奥诊所诊断为良性乳腺疾病的女性（n=2666）进行了嵌套队列研究，并且在诊断后 6 个月内可获得乳房 X 光检查。对女性进行了平均 13.3 年的随访，以记录任何乳腺癌的发病率。小叶退化分为无、部分或完全；使用 Wolfe 分类法将实质模式分为 N1（非致密型）、P1、P2（导管突出占乳房的<25%或>25%，分别）或 DY（极致密型）。使用调整后的 Cox 比例风险模型估计小叶退化和 MBD 与乳腺癌风险之间的关联的风险比（HR）和 95%置信区间（CI）。所有统计学检验均为双侧。
在调整 MBD 后，无或部分小叶退化与更高的乳腺癌风险相关，而完全退化则无此相关性（无：乳腺癌发病率的 HR=2.62，95%CI=1.39-4.94；部分：乳腺癌发病率的 HR=1.61，95%CI=1.03-2.53；P（趋势）=0.002）。同样，在调整退化后，致密乳房与更高的乳腺癌风险相关，而非致密乳房（对于 DY：乳腺癌发病率的 HR=1.67，95%CI=1.03-2.73；对于 P2：乳腺癌发病率的 HR=1.96，95%CI=1.20-3.21；对于 P1：乳腺癌发病率的 HR=1.23，95%CI=0.67-2.26；P（趋势）=0.02）。无退化和致密乳房的组合与更高的乳腺癌风险相关，而完全退化和非致密乳房则无此相关性（乳腺癌发病率的 HR=4.08，95%CI=1.72-9.68；P=0.006）。
小叶退化和 MBD 与乳腺癌的发生率独立相关；两者结合在一起，与乳腺癌的风险甚至更高。
