Lilge Lothar, Terry Mary Beth, Walter Jane, Pinnaduwage Dushanthi, Glendon Gord, Hanna Danielle, Tammemagi Mai-Liis, Bradbury Angela, Buys Saundra, Daly Mary, John Esther M, Knight Julia A, Andrulis Irene L
Princess Margaret Cancer Centre, University Health Network, 101 College Street, Toronto, ON, M5G1L7, Canada.
Medical Biophysics, University of Toronto, 101 College Street, Toronto, ON, M5G1L7, Canada.
Breast Cancer Res. 2017 Feb 6;19(1):12. doi: 10.1186/s13058-017-0805-x.
Tanner staging (TS), a five-stage classification indicating no breast tissue (TS1) to full breast development (TS5), is used both in health research and clinical care to assess the onset of breast development (TS2) and duration in each stage. Currently, TS is measured both visually and through palpation but non-invasive methods will improve comparisons across settings.
We used optical spectroscopy (OS) measures from 102 girls at the Ontario site of the LEGACY girls study (average age 12 years, range 10.0-15.4 years) to determine whether breast tissue optical properties map to each TS. We further examined whether these properties differed by age, body mass index (BMI), and breast cancer risk score (BCRS) by examining the major principal components (PC).
Age and BMI increased linearly with increasing TS. Eight PCs explained 99.9% of the variation in OS data. Unlike the linear increase with age and BMI, OS components had distinct patterns by TS: the onset of breast development (TS1 to TS2) was marked by elevation of PC3 scores indicating an increase in adipose tissue and decrease in signal from the pectoral muscle; transition to TS3 was marked by elevation of PC6 and PC7 and decline of PC2 scores indicating an increase in glandular or dense tissue; and transition to TS4+ by decline of PC2 scores representing a further increase in glandular tissue relative to adipose tissue. Of the eight PCs, three component scores (PC4, PC5, and PC8) remained in the best-fitting model of BCRS, suggesting different levels of collagen in the breast tissue by BCRS.
Our results suggest that serial measures of OS, a non-invasive assessment of breast tissue characteristics, can be used as an objective outcome that does not rely on visual inspection or palpation, for studying drivers of breast development.
坦纳分期（TS）是一种五阶段分类法，用于表示从无乳腺组织（TS1）到乳腺完全发育（TS5）的过程，在健康研究和临床护理中均用于评估乳腺发育的起始（TS2）以及各阶段的持续时间。目前，TS通过视觉检查和触诊来测量，但非侵入性方法将改善不同环境下的比较。
我们使用了来自LEGACY女孩研究安大略站点的102名女孩（平均年龄12岁，范围10.0 - 15.4岁）的光谱学（OS）测量数据，以确定乳腺组织光学特性是否与每个TS相对应。我们还通过检查主要主成分（PC），进一步研究了这些特性是否因年龄、体重指数（BMI）和乳腺癌风险评分（BCRS）而有所不同。
年龄和BMI随着TS的增加呈线性增长。八个主成分解释了OS数据中99.9%的变异。与年龄和BMI的线性增长不同，OS成分在不同TS阶段有明显模式：乳腺发育开始（TS1到TS2）的特征是PC3得分升高，表明脂肪组织增加，胸肌信号减少；向TS3过渡的特征是PC6和PC7升高，PC2得分下降，表明腺体或致密组织增加；向TS4+过渡的特征是PC2得分下降，表明相对于脂肪组织，腺体组织进一步增加。在八个主成分中，三个成分得分（PC4、PC5和PC8）保留在BCRS的最佳拟合模型中，表明不同BCRS水平下乳腺组织中的胶原蛋白含量不同。
我们的结果表明，光谱学（OS）的系列测量，即对乳腺组织特征的非侵入性评估，可作为一种不依赖视觉检查或触诊的客观结果，用于研究乳腺发育的驱动因素。
