International Pooling Project of Mammographic Density

描述(由申请人提供)：乳房中纤维腺体组织比例较高的女性，而不是脂肪组织，在接下来的10年或更长时间内患乳腺癌的风险增加(高达5倍)。这种属性被称为乳房X光照相密度(MD)，在不同的女性之间会有所不同，并且在同一个女性体内会随着时间的推移而变化。由于既有遗传因素又有环境决定因素，国家之间的MD差异可能解释了乳腺癌发病率国际差异的6倍以上。到目前为止，只有一项研究对此进行了调查，即美国/夏威夷/日本的比较(Maskarinec等人。2007)。我们的目标是启动一个更广泛的国际乳腺摄影密度池项目，以：(I)汇集和获得跨越乳腺癌发病范围的国家的MD标准化可比数据；(Ii)描述MD总体和年龄特定的MD分布的国际差异，并评估它们是否可由MD的个体水平风险因素解释；(Iii)量化MD的国际差异与相应的乳腺癌发病率和Pike提出的乳腺组织老化模型的程度；(Iv)评估一系列MD指标(绝对/相对/特定年龄/累积)；(V)继续并将这一汇集的资源扩大到未来。乳房摄影密度国际汇集项目将是MD的第一个此类举措，以后可以扩大到包括MD测量的新方法、成像方式和更广泛的决定因素。在国际癌症研究机构的领导下，我们强调从国际角度看待这一标记物，特别是迫在眉睫，因为乳腺癌现在是世界上几乎每个国家女性最常见的癌症。如果MD确实是乳腺癌发病率的国际差异的基础，对MD分布的监测将成为乳腺癌风险变化的重要早期指标。 与公众健康相关：在所有女性的乳房X光检查中，可以测量到的乳腺癌风险的最强量化标志之一是乳房X光检查密度。关于乳房摄影密度的国际集合项目将创建第一个标准化的集合数据/影像资源，其中包括所有大洲的妇女。它将被用来描述和解释乳房X光照相密度的国际差异，以及它们在多大程度上解释了乳腺癌发病率的国际差异。

DESCRIPTION (provided by applicant): Women with a high percentage of fibroglandular tissue in their breast, as opposed to fatty tissue, have an increased breast cancer risk (up to 5-fold higher) in the subsequent 10 or more years. This attribute, known as mammographic density (MD), varies between women and can change within the same woman over time. Having both genetic and environmental determinants, between-country differences in MD may account for the over 6-fold international variations in breast cancer incidence rates. Only one study has investigated this to date, i.e. a US/Hawaii/Japanese comparison (Maskarinec et al. 2007). We aim to initiate a more widespread International Pooling Project of Mammographic Density to: (i) pool and obtain standardised comparable data on MD from countries spanning the breast cancer incidence range; (ii) describe international variations in overall and age-specific MD distributions and assess whether they are explained by individual-level risk factors for MD; (iii) quantify the extent to which international variations in MD correlated with corresponding breast cancer incidence rates and Pike's proposed model of breast tissue ageing; (iv) assess a range of MD metrics (absolute/relative/age-specific/cumulative); (v) continue and expand this pooled resource into the future. The International Pooling Project of Mammographic Density would be the first such initiative for MD, which could later be expanded to include new methods of MD measurement, imaging modalities and a broader range of determinants. Being led by the International Agency for Research on Cancer, we emphasize an international perspective for this marker, especially urgent as breast cancer is now the most common cancer in women in almost every country worldwide. If MD does underpin international variations in breast cancer incidence, the monitoring of MD-distributions would become an important early indicator of changes in breast cancer risk. PUBLIC HEALTH RELEVANCE: One of the strongest quantitative markers of breast cancer risk measurable on a mammogram in all women is mammographic density. The International Pooling Project on Mammographic Density will create the first standardized pooled data/imaging resource that includes women from all continents. It will be used to describe and account for international variations in mammographic density and to what extent they account for international variations in breast cancer incidence rates.