Straatman H, Peer P G, Verbeek A L
University of Nijmegen, Department of Epidemiology, The Netherlands.
Biometrics. 1997 Mar;53(1):217-29.
Early indicators of the effectiveness of a screening test for chronic diseases such as breast cancer are the length of time the diagnosis is advanced by screening, the lead time, and the sensitivity of the screening test. This paper describes a model for simultaneously estimating the mean lead time and the sensitivity when only the number of cancers detected at the successive screenings and the number of cancers occurring in the time interval between the screening examinations are known. This model is particularly useful in assessing the effect of screening when the underlying cancer incidence in the screened group is unknown. The model is fitted to the data of 235 screen-detected breast cancer cases and 146 interval cancers diagnosed across 6 screening rounds of the program in Nijmegen. The maximum likelihood estimate for the mean lead time ranges from 1.3 years in the under age 50 group to 2.2 years in the age 50-65 group, both estimates having large confidence intervals. The corresponding sensitivity estimates are 0.92 and 1.00.
对于诸如乳腺癌等慢性疾病的筛查测试，其有效性的早期指标包括通过筛查提前诊断的时间长度（即领先时间）以及筛查测试的灵敏度。本文描述了一种模型，当仅知道在连续筛查中检测出的癌症数量以及在筛查检查之间的时间间隔内发生的癌症数量时，可同时估计平均领先时间和灵敏度。当筛查组中潜在的癌症发病率未知时，该模型在评估筛查效果方面特别有用。该模型应用于奈梅亨一项计划的6轮筛查中检测出的235例筛查发现的乳腺癌病例和146例间隔期癌症的数据。平均领先时间的最大似然估计值在50岁以下组为1.3年，在50 - 65岁组为2.2年，这两个估计值都有较大的置信区间。相应的灵敏度估计值分别为0.92和1.00。
