HRT AND CHANGES IN MAMMOGRAPHIC DENSITY

描述：乳房实质模式在乳房X线照片上描绘为 射线照相密度的变化，其对应于相对量 脂肪组织（参见，上皮和基质组织）。 乳房摄影 密度在上皮细胞比例最大的女性中最高， 基质和结缔组织。 与无密度相比，高密度（>50%） 一直与显著升高的长期 乳腺癌风险，与年龄、绝经状态或其他乳腺疾病无关， 癌症危险因素。 最近，几个小的案例表明， 绝经后激素替代疗法可能会增加某些绝经后妇女的密度， 尽管选择偏差和对暴露和结果的不精确测量 （密度）降低了这些结果的有效性。 鉴于小，但 HRT与乳腺癌风险增加的持续相关性， 绝经后妇女中HRT使用的流行率增加，评估 HRT对乳腺摄影密度的影响的大小和相关性可能 有助于更好地了解外源性 激素和公共卫生乳腺癌预防工作。 的 目的是：1）可靠地估计HRT对 绝经后妇女的乳腺摄影密度; 2）确定是否 HRT相关的密度变化因种族、年龄、绝经后时间而异， 体重或其他乳腺癌风险因素。 这项研究是辅助性的 WHI是一项长期、多中心、随机试验， 绝经后妇女。 WHI参与者被分配到HRT（仅雌激素 对于子宫切除的妇女，或联合孕激素-雌激素用于 子宫）或安慰剂。 与WHI临床中心合作， 将由参与者乳房X光片上的乳房密度百分比组成 在基线、1年和2年随访间隔时采集，然后 比较处理组之间的纵向密度变化。 样品 由1 200名妇女组成，四个族裔群体的人数充足： 欧洲人、非洲人、西班牙裔和亚洲/太平洋岛民。

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.