QUANTITATIVE CLASSIFICATION OF MAMMOGRAPHIC DENSITIES AND BREAST-CANCER RISK - RESULTS FROM THE CANADIAN NATIONAL BREAST SCREENING STUDY
QUANTITATIVE CLASSIFICATION OF MAMMOGRAPHIC DENSITIES AND BREAST-CANCER RISK - RESULTS FROM THE CANADIAN NATIONAL BREAST SCREENING STUDY
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DOI：
10.1093/jnci/87.9.670
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发表时间：
1995-05-03
期刊：
影响因子：
--
通讯作者：
YAFFE, MJ
中科院分区：
文献类型：
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作者：
BOYD, NF;BYNG, JW;YAFFE, MJ
背景资料：女性乳房的放射学表现因女性而异，这取决于存在的脂肪、结缔组织和上皮组织的相对量，乳房组织的乳房X线摄影密度的变化被称为乳房的实质模式，脂肪在放射学上是半透明或透明的。（较暗的外观），结缔组织和上皮组织在放射学上都是致密的以前的研究普遍支持实质模式和乳腺癌风险之间的关联（密度越大，风险越大），但报告的风险估计存在相当大的异质性，目的：我们的目的是通过传统放射学方法和新型计算机辅助方法对乳腺密度进行定量分类，确定与不同乳腺摄影密度相关的乳腺癌风险水平。方法：加拿大国家乳腺癌筛查研究（NBSS）是一项多中心、随机试验，根据一组45000名接受乳房X光检查的妇女的医疗记录，确定了来自354名病例受试者和354名对照受试者的乳房X线照片，病例受试者选自那些在进入试验后12个月或更长时间内发生了组织学证实的浸润性乳腺癌的妇女，对照受试者选自那些年龄相似、经过相似的观察期后没有发生乳腺癌的妇女，在NBSS开始时拍摄的乳房X线照片是用于测量的图像，乳房X线照片被分为六类密度，由放射科医生或通过计算机辅助测量，所有放射学分类和计算机-使用病例受试者的癌症部位对侧乳房和对照受试者的相应乳房的一个头尾位视图进行辅助测量，所有P值代表统计学显著性的双侧检验，结果：对于所有受试者，由放射科医生确定的较低密度和下一个较高密度类别之间的相对风险（RR）增加了43%，并且由计算机辅助方法确定的相对风险增加了32%。最广泛类别相对于最少类别的RR为6.05（放射科医师的95%置信区间[CI] = 2.82-12.97）和4.04（95% CI = 2.12-7.69）对于计算机辅助方法，放射科医生和计算机辅助方法都发现，40岁以下的女性患乳腺癌的风险在统计学上显著增加，49岁（放射科医生P = 0.005，计算机辅助测量P = 0.003）和50-59岁（放射科医生P = 0.002，计算机辅助测量P = 0.001），结论：这些结果表明，乳腺X线摄影评估的乳腺组织密度水平的增加与乳腺癌风险的增加有关。
Background: The radiographic appearance of the female breast varies from woman to woman depending on the relative amounts of fat and connective and epithelial tissues present, Variations in the mammographic density of breast tissue are referred to as the parenchymal pattern of the breast, Fat is radiologically translucent or clear (darker appearance), and both connective and epithelial tissues are radiologically dense (lighter appearance), Previous studies have generally supported an association between parenchymal patterns and breast cancer risk (greater risk with increasing densities), but there has been considerable heterogeneity in risk estimates reported, Purpose: Our objective was to determine the level of breast cancer risk associated with varying mammographic densities by quantitatively classifying breast density with conventional radiological methods and novel computer-assisted methods, Methods: From the medical records of a cohort of 45000 women assigned to mammography in the Canadian National Breast Cancer Screening Study (NBSS), a multicenter, randomized trial, mammograms from 354 case subjects and 354 control subjects were identified, Case subjects were selected from those women in whom histologically verified invasive breast cancer had developed 12 months or more after entering the trial, Control subjects were selected from those of similar age who, after a similar period of observation, had not developed breast cancer, The mammogram taken at the beginning of the NBSS was the image used for measurements, Mammograms were classified into six categories of density, either by radiologists of by computer-assisted measurements, All radiological classification and computer-assisted measurements were made using one craniocaudal view from the breast contralateral to the cancer site in case subjects and the corresponding breast of control subjects, All P values represent two-sided tests of statistical significance, Results: For ail subjects, there was a 43% increase in the relative risk (RR) between the lower and the next higher category of density, as determined by radiologists, and there was a 32% increase as determined by the computer-assisted method, For all subjects, the RR in the most extensive category relative to the least was 6.05 (95% confidence interval [CI] = 2.82-12.97) for radiologists and 4.04 (95% CI = 2.12-7.69) for computer-assisted methods, Statistically significant increases in breast cancer risk associated with increasing mammographic density were found by both radiologists and computer-assisted methods for women in the age category 40-49 years (P = .005 for radiologists and P = .003 for computer-assisted measurements) and the age category 50-59 years (P = .002 for radiologists and P = .001 for computer-assisted measurements), Conclusion: These results show that increases in the level of breast tissue density as assessed by mammography are associated with increases in risk for breast cancer.