McCann J, Stockton D, Day N
University of Cambridge, Department of Community Medicine, UK.
J Med Screen. 1998;5(1):42-8. doi: 10.1136/jms.5.1.42.
To assess the impact of the National Health Service breast screening programme on overall and stage-specific incidence of breast cancer in East Anglia; also, to predict the magnitude of the screening induced reduction in breast cancer mortality.
Women resident in East Anglia aged 50-69, diagnosed between 1976 and 1995.
Comparison of numbers and incidence of breast cancer by age, stage, and mode of detection; investigation of relative contributions of advanced (stages II, III, and IV) cancers to total incidence by detection mode; estimation of the reduction in advanced cancer incidence.
There has been a large increase in early stage incidence in the age group 50-64 targeted by the screening programme. By 1995, the estimated decrease in advanced cancer incidence was between 7 and 19%. In 1995, of all breast cancers arising in the age group 50-69 years, 33% were screen detected, 27% were interval cancers, 15% were in non-attenders, 9% were in lapsed attenders, 7% occurred before invitation, and 4% arose in women outside the birth year range for invitation. Of the advanced cancers diagnosed in 1995, 31% were interval cancers, 20% were screen detected, 19% were in non-attenders, 12% were in lapsed attenders, 8% occurred before invitation, and 4% presented in women outside the birth year range for invitation.
Screening has brought about a large increase in detection of early stage cancers. This increase has not yet been fully matched by a corresponding deficit in advanced cancers, possibly because the full effect of screening has not yet been achieved. Reducing the proportion of interval cancers is necessary to increase the effect of screening on mortality.
评估国民医疗服务体系乳腺癌筛查项目对东安格利亚地区乳腺癌总体发病率及特定分期发病率的影响；同时，预测筛查导致的乳腺癌死亡率降低幅度。
居住在东安格利亚地区、年龄在50 - 69岁之间、于1976年至1995年期间被诊断出乳腺癌的女性。
按年龄、分期和检测方式比较乳腺癌的数量和发病率；调查晚期（II、III和IV期）癌症对不同检测方式下总发病率的相对贡献；估计晚期癌症发病率的降低情况。
筛查项目所针对的50 - 64岁年龄组早期发病率大幅上升。到1995年，晚期癌症发病率估计下降了7%至19%。1995年，在50 - 69岁年龄组中发生的所有乳腺癌中，33%是通过筛查发现的，27%是筛查间隔期癌症，15%是未参加筛查者，9%是曾参加筛查但后来不再参加者，7%是在被邀请筛查之前发病，4%是在筛查邀请出生年份范围之外的女性中发病。在1995年诊断出的晚期癌症中，31%是筛查间隔期癌症，20%是通过筛查发现的，19%是未参加筛查者，12%是曾参加筛查但后来不再参加者，8%是在被邀请筛查之前发病，4%是在筛查邀请出生年份范围之外的女性中发病。
筛查使早期癌症的检出率大幅提高。晚期癌症相应减少的幅度尚未完全与之匹配，可能是因为筛查的全部效果尚未实现。减少筛查间隔期癌症的比例对于提高筛查对死亡率的影响是必要的。
