HRT AND CHANGES IN MAMMOGRAPHIC DENSITY

描述：乳房实质图案在乳房X光照片上描绘为 射线照相密度的变化，对应于相对量 脂肪组织(包括上皮组织和间质组织)。乳房X光摄影 上皮样细胞比例最大的女性密度最高， 间质和结缔组织。与无密度相比，高密度(50%) 一直与显著提高的长期 乳腺癌风险，与年龄、绝经状态或其他乳房无关 癌症风险因素。最近，几个小案例系列表明 绝经后激素替代疗法可能会增加一些绝经后妇女的密度， 尽管选择存在偏见，对暴露和结果的衡量也不准确 (密度)减损这些结果的有效性。虽然很小，但 激素替代疗法与乳腺癌风险增加的持续关联，以及 在绝经后妇女中使用HRT的流行率增加，评估 HRT对乳腺X线摄影密度的影响的大小和相关因素可能 有助于更好地理解外源性疾病的病因学作用 荷尔蒙和公共卫生乳腺癌的预防努力。这个 目标是：1)可靠地估计HRT对 绝经后妇女的乳房X光摄影密度；和2)决定 与激素替代疗法相关的密度变化因种族、年龄、绝经时间、 体重或其他乳腺癌危险因素。这项研究是辅助的。 到WHI，一项长期、多中心、随机的HRT试验 绝经后的女性。WHI参与者被分配到激素替代疗法(仅限雌激素 对于子宫切除的女性，或孕激素和雌激素联合治疗的女性 子宫)或安慰剂。与WHI临床中心合作，测量 将由参与者乳房X光照片上的乳房密度百分比组成 在基线、一年和两年的随访间隔时间进行调查，然后 比较各治疗组间的纵向密度变化。样本 由1200名妇女组成，在四个种族中有足够的人数： 欧洲、非洲、西班牙裔和亚洲/太平洋岛民美国人。

DESCRIPTION: Breast parenchymal patterns are depicted on mammograms as variations in radiographic density, which correspond to the relative amounts of fatty tissue (c.f., epithelial and stromal tissues). Mammographic density is highest in women with the greatest proportion of epithelial, stromal and connective tissues. Compared to no density, high density (>50%) has been consistently associated with significantly elevated long-term breast cancer risk, independent of age, menopausal status, or other breast cancer risk factors. Recently, several small case series have suggested that postmenopausal HRT may increase density in some postmenopausal women, although selection biases and imprecise measurement of exposure and outcomes (density) detract from the validity of these results. Given the small but persistent association of HRT with increased risk of breast cancer, and the increasing prevalence of HRT use among postmenopausal women, assessing the magnitude and correlates of the effect of HRT on mammographic density may contribute to improved understanding of the aetiologic role of exogenous hormones and to public health breast cancer prevention efforts. The objectives are to: 1) reliably estimate the quantitative effect of HRT on mammographic density in postmenopausal women; and 2) determine whether HRT-related density changes differ by ethnicity, age, time since menopause, body mass, or other breast cancer risk factors. This research is ancillary to the WHI, a long-term, multi-center, randomized trial of HRT in postmenopausal women. WHI participants are assigned to HRT (estrogen only for hysterectomized women, or combined progestin-estrogen for women with a uterus) or placebo. Working with the WHI clinical centers, measurements will be made of the percentage of breast density on participants' mammograms taken at baseline, one-year and two-year follow-up intervals, and then compared for longitudinal density change among treatment groups. The sample is comprised of 1200 women with adequate numbers in four ethnic groups: European, African, Hispanic and Asian/Pacific Islander Americans.