Burhenne H J, Burhenne L W, Goldberg F, Hislop T G, Worth A J, Rebbeck P M, Kan L
Department of Radiology, University of British Columbia, Vancouver General Hospital, Canada.
AJR Am J Roentgenol. 1994 May;162(5):1067-71; discussion 1072-5. doi: 10.2214/ajr.162.5.8165983.
Interval cancers in an annual mammography screening program are defined as cancers detected within 12 months after a mammographic screening in which findings are considered normal. Our objective was to analyze interval cancers for histologic type, tumor size, staging, and histologic grade. A classification for interval cancers is presented. Detection of interval cancers is an integral part of quality control and is required for the establishment of sensitivity rates for screening mammography, a necessary part of implementing the recommendations for breast cancer screening.
A total of 47,583 mammographic screening examinations of 38,219 women were available for review for the period of July 1988 to March 1991. Linkage with the provincial population-based cancer registry provided identification of all interval cancers of the breast. Histologic analysis of breast cancers was provided by an internationally recognized breast cancer pathologist who interpreted the specimens twice.
A total of 207 breast cancers were detected at mammographic screening (true-positive cancers) during the first 33 months of the program, and 37 interval cancers were identified during the 33 months of screening plus a 12-month interval. Blinded review by three radiologists experienced in screening mammography resulted in classification of 21 of 37 cases as true interval cancers and 16 cases as misses. No interval cancers were missed because of poor mammographic technique. The sensitivity of screening mammography was 85%, 63% for patients less than 50 years old and 89% for patients more than 50 years old. The specificity was 93% for all patients (both younger and older than 50 years).
The availability of a population-based cancer registry in the province of British Columbia makes an accurate determination of interval cancers and sensitivity rates possible. These data are essential for quality analysis, program planning, and education of radiologists in screening mammography. There were more true interval cancers than misses, and histologic analysis demonstrated that the majority of interval cancers were in stages I and II.
年度乳腺钼靶筛查项目中的间期癌被定义为在钼靶筛查结果被认为正常后的12个月内检测出的癌症。我们的目的是分析间期癌的组织学类型、肿瘤大小、分期和组织学分级。本文提出了一种间期癌的分类方法。间期癌的检测是质量控制的一个组成部分，也是确定乳腺钼靶筛查敏感度的必要条件，而这是实施乳腺癌筛查建议的一个必要部分。
在1988年7月至1991年3月期间，共有38219名女性的47583次乳腺钼靶筛查检查可供审查。与省级基于人群的癌症登记处的关联提供了所有乳腺间期癌的识别信息。乳腺癌的组织学分析由一位国际公认的乳腺癌病理学家进行，该病理学家对标本进行了两次解读。
在该项目的前33个月中，乳腺钼靶筛查共检测出207例乳腺癌（真阳性癌），在33个月的筛查加上12个月的间期内，共识别出37例间期癌。三位有乳腺钼靶筛查经验的放射科医生进行的盲法审查将37例病例中的21例分类为真正的间期癌，16例为漏诊。没有因为钼靶技术不佳而漏诊间期癌。乳腺钼靶筛查的敏感度为85%，50岁以下患者为63%，50岁以上患者为89%。所有患者（包括50岁以下和50岁以上）的特异度为93%。
不列颠哥伦比亚省省级基于人群的癌症登记处的存在使得准确确定间期癌和敏感度成为可能。这些数据对于质量分析、项目规划以及乳腺钼靶筛查中放射科医生的培训至关重要。真正的间期癌比漏诊的更多，组织学分析表明，大多数间期癌处于I期和II期。
