Boyd Norman, Martin Lisa, Stone Jennifer, Little Laurie, Minkin Salomon, Yaffe Martin
The Division of Epidemiology and Statistics, Ontario Cancer Institute, Toronto, Ontario, Canada.
Cancer Epidemiol Biomarkers Prev. 2002 Oct;11(10 Pt 1):1048-53.
Menopause has an important influence on risk of breast cancer. We have examined longitudinally the effect of menopause on mammographic densities, a strong risk factor for the disease, in women in the Canadian National Breast Screening Study. Baseline mammograms from women in the National Breast Screening Study, who were premenopausal at entry and had undergone menopause after entry, were compared with the mammogram that most closely followed menopause, using a computer-assisted method of measurement. The changes seen in the mammograms of these subjects were compared with those in an age-matched group of women who were also premenopausal at entry, had been followed for the same length of time, and had not experienced menopause. The results of this longitudinal study show that menopause has effects on characteristics of the mammogram that, over the same period of time, are greater than the effects of age. These effects are a reduction in the area of radiologically dense tissue, an increase in the area of nondense tissue, and a decrease in the percentage of density. However, these changes do not fully account for the effects of age on mammographic densities seen in cross-sectional data. Menopause is associated with distinct changes in the mammogram that account for some, but not all, of the observed association of increasing age with decreasing percentage of mammographic density. The observed changes in the morphology of the breast may explain some of the effect that menopause has on breast cancer risk.
绝经对乳腺癌风险有重要影响。在加拿大国家乳腺筛查研究中，我们纵向研究了绝经对乳腺钼靶密度（该疾病的一个强风险因素）的影响。使用计算机辅助测量方法，将国家乳腺筛查研究中入组时为绝经前且入组后经历了绝经的女性的基线乳腺钼靶片，与绝经后最接近的一次乳腺钼靶片进行比较。将这些受试者乳腺钼靶片上的变化，与年龄匹配且入组时同样为绝经前、随访时间相同且未经历绝经的女性组的变化进行比较。这项纵向研究结果表明，在相同时间段内，绝经对乳腺钼靶特征的影响大于年龄的影响。这些影响包括放射致密组织面积减少、非致密组织面积增加以及密度百分比降低。然而，这些变化并不能完全解释横断面数据中年龄对乳腺钼靶密度的影响。绝经与乳腺钼靶的明显变化相关，这些变化解释了观察到的年龄增长与乳腺钼靶密度百分比降低之间部分而非全部的关联。观察到乳房形态的变化可能解释了绝经对乳腺癌风险产生的部分影响。
