RAND Corporation, Santa Monica, California.
Decision and Infrastructure Sciences Division, Argonne National Laboratory, Lemont, Illinois.
Cancer Epidemiol Biomarkers Prev. 2022 Apr 1;31(4):775-782. doi: 10.1158/1055-9965.EPI-21-1001.
Models can help guide colorectal cancer screening policy. Although models are carefully calibrated and validated, there is less scrutiny of assumptions about test performance.
We examined the validity of the CRC-SPIN model and colonoscopy sensitivity assumptions. Standard sensitivity assumptions, consistent with published decision analyses, assume sensitivity equal to 0.75 for diminutive adenomas (<6 mm), 0.85 for small adenomas (6-10 mm), 0.95 for large adenomas (≥10 mm), and 0.95 for preclinical cancer. We also selected adenoma sensitivity that resulted in more accurate predictions. Targets were drawn from the Wheat Bran Fiber study. We examined how well the model predicted outcomes measured over a three-year follow-up period, including the number of adenomas detected, the size of the largest adenoma detected, and incident colorectal cancer.
Using standard sensitivity assumptions, the model predicted adenoma prevalence that was too low (42.5% versus 48.9% observed, with 95% confidence interval 45.3%-50.7%) and detection of too few large adenomas (5.1% versus 14.% observed, with 95% confidence interval 11.8%-17.4%). Predictions were close to targets when we set sensitivities to 0.20 for diminutive adenomas, 0.60 for small adenomas, 0.80 for 10- to 20-mm adenomas, and 0.98 for adenomas 20 mm and larger.
Colonoscopy may be less accurate than currently assumed, especially for diminutive adenomas. Alternatively, the CRC-SPIN model may not accurately simulate onset and progression of adenomas in higher-risk populations.
Misspecification of either colonoscopy sensitivity or disease progression in high-risk populations may affect the predicted effectiveness of colorectal cancer screening. When possible, decision analyses used to inform policy should address these uncertainties.See related commentary by Etzioni and Lange, p. 702.
模型可以帮助指导结直肠癌筛查政策。尽管模型经过了精心校准和验证，但对于测试性能的假设却缺乏更严格的审查。
我们检验了 CRC-SPIN 模型和结肠镜检查敏感性假设的有效性。标准敏感性假设与已发表的决策分析一致，假设微小腺瘤（<6mm）的敏感性为 0.75，小腺瘤（6-10mm）为 0.85，大腺瘤（≥10mm）为 0.95，临床前期癌症为 0.95。我们还选择了敏感性更高的腺瘤检测假设。目标是从 Wheat Bran Fiber 研究中抽取。我们考察了模型在预测为期三年的随访期间的结果方面的表现，包括检测到的腺瘤数量、最大腺瘤的大小和结直肠癌的发生率。
使用标准敏感性假设，模型预测的腺瘤患病率过低（42.5%vs.观察到的 48.9%，95%置信区间为 45.3%-50.7%），并且检测到的大腺瘤数量过少（5.1%vs.观察到的 14.0%，95%置信区间为 11.8%-17.4%）。当我们将微小腺瘤的敏感性设定为 0.20、小腺瘤为 0.60、10-20mm 腺瘤为 0.80、20mm 及以上腺瘤为 0.98 时，预测结果与目标接近。
结肠镜检查的准确性可能不如目前假设的那样高，尤其是对微小腺瘤。或者，CRC-SPIN 模型可能无法准确模拟高危人群中腺瘤的发生和进展。
在高危人群中，无论是结肠镜检查的敏感性还是疾病进展的假设不正确，都可能影响结直肠癌筛查的预测效果。在可能的情况下，用于为政策提供信息的决策分析应该解决这些不确定性。另见 Etzioni 和 Lange的相关评论，第 702 页。
