Holland R, Mravunac M, Hendriks J H, Bekker B V
Cancer. 1982 Jun 15;49(12):2527-33. doi: 10.1002/1097-0142(19820615)49:12<2527::aid-cncr2820491220>3.0.co;2-e.
Within a population-based breast cancer screening programs, 209 cancers were detected by regular mammographic screening. Additionally, 66 cancers were discovered between two consecutive screenings after one, two, or three negative screening examinations (interval cancers). The study group consisted of 25,920 women who have been participating since 1975 in a breast cancer screening program in Nijmegen, the Netherlands. In this program, single view mammography (lateromedial projection) was administered as the sole screening examination every two years. Physical examination was not part of the screening program. All previous histologic and radiologic material from 64 of those "interval" patients was available and was reviewed. In 19 of the 64 patients, direct or indirect signs of tumor were seen on the previous screening mammogram on review (observers error). In four cases the site of the tumor lay outside the imaging field (technical error). In 41 cases, no signs of tumor could be seen on the mammograms even on review. By calculated tumor doubling times, 20 of these 41 cases were probably too small to be detected at the last screening ("real" interval cancers). However, 21 cases were probably large enough but were somehow masked from radiologic detection. The mean reasons for this "masking" proved to be: 1) dense breast, 2) poorly outlined tumor mass of diffuse infiltrative type, mainly invasive lobular carcinomas, and 3) intraductal localization. The authors suggest that women with dense breasts be screened more frequently, using more views and modalities and with broader criteria for advising surgical biopsy. They also note that in general the two-year interval between screenings is probably longer than the optimal interval.
在一项基于人群的乳腺癌筛查项目中，通过定期乳房X光筛查发现了209例癌症。此外，在连续两次筛查之间，经过一、二或三次阴性筛查后发现了66例癌症（间期癌）。研究组由自1975年以来一直在荷兰奈梅亨参加乳腺癌筛查项目的25920名女性组成。在该项目中，每两年进行一次单视图乳房X光检查（内外侧投照）作为唯一的筛查检查。体格检查不属于筛查项目。对其中64例“间期”患者以前所有的组织学和放射学资料进行了复查。在64例患者中的19例中，复查以前的筛查乳房X光片时发现了肿瘤的直接或间接征象（观察者误差）。4例肿瘤位于成像视野之外（技术误差）。在41例中，即使复查乳房X光片也未见肿瘤征象。通过计算肿瘤倍增时间，这41例中的20例可能在最后一次筛查时太小而无法被检测到（“真正的”间期癌）。然而，21例可能已经足够大，但不知何故在放射学检查中被掩盖了。这种“掩盖”的主要原因是：1）乳腺致密，2）弥漫浸润型肿瘤块轮廓不清，主要是浸润性小叶癌，3）导管内定位。作者建议，对于乳腺致密的女性，应增加筛查频率，采用更多的投照角度和检查方式，并采用更宽泛的标准来建议手术活检。他们还指出，一般来说，筛查间隔两年可能比最佳间隔时间更长。
