Lansdorp-Vogelaar Iris, van Ballegooijen Marjolein, Boer Rob, Zauber Ann, Habbema J Dik F
Department of Public Health, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
Cancer. 2009 Jun 1;115(11):2410-9. doi: 10.1002/cncr.24256.
Estimates of the fecal occult blood test (FOBT) (Hemoccult II) sensitivity differed widely between screening trials and led to divergent conclusions on the effects of FOBT screening. We used microsimulation modeling to estimate a preclinical colorectal cancer (CRC) duration and sensitivity for unrehydrated FOBT from the data of 3 randomized controlled trials of Minnesota, Nottingham, and Funen. In addition to 2 usual hypotheses on the sensitivity of FOBT, we tested a novel hypothesis where sensitivity is linked to the stage of clinical diagnosis in the situation without screening.
We used the MISCAN-Colon microsimulation model to estimate sensitivity and duration, accounting for differences between the trials in demography, background incidence, and trial design. We tested 3 hypotheses for FOBT sensitivity: sensitivity is the same for all preclinical CRC stages, sensitivity increases with each stage, and sensitivity is higher for the stage in which the cancer would have been diagnosed in the absence of screening than for earlier stages. Goodness-of-fit was evaluated by comparing expected and observed rates of screen-detected and interval CRC.
The hypothesis with a higher sensitivity in the stage of clinical diagnosis gave the best fit. Under this hypothesis, sensitivity of FOBT was 51% in the stage of clinical diagnosis and 19% in earlier stages. The average duration of preclinical CRC was estimated at 6.7 years.
Our analysis corroborated a long duration of preclinical CRC, with FOBT most sensitive in the stage of clinical diagnosis.
粪便潜血试验（FOBT，Hemoccult II法）的敏感性在筛查试验中的估计差异很大，导致对FOBT筛查效果得出了不同结论。我们使用微观模拟模型，根据明尼苏达、诺丁汉和菲英岛的3项随机对照试验数据，估计未复水FOBT对临床前期结直肠癌（CRC）的持续时间和敏感性。除了关于FOBT敏感性的2种常见假设外，我们还测试了一种新假设，即在无筛查情况下，敏感性与临床诊断阶段相关。
我们使用MISCAN - Colon微观模拟模型来估计敏感性和持续时间，同时考虑试验在人口统计学、背景发病率和试验设计方面的差异。我们测试了FOBT敏感性的3种假设：所有临床前期CRC阶段的敏感性相同；敏感性随每个阶段增加；在无筛查时癌症会被诊断的阶段的敏感性高于早期阶段。通过比较筛查发现的CRC和间隔期CRC的预期率与观察率来评估拟合优度。
临床诊断阶段敏感性较高的假设拟合效果最佳。在此假设下，FOBT在临床诊断阶段的敏感性为51%，在早期阶段为19%。临床前期CRC的平均持续时间估计为6.7年。
我们的分析证实了临床前期CRC持续时间较长，FOBT在临床诊断阶段最敏感。
