a Department of Surgery , University of Helsinki and Helsinki University Hospital , Helsinki , Finland.
b Department of Radiology , University of Helsinki and Helsinki University Hospital , Helsinki , Finland.
Acta Oncol. 2018 Jun;57(6):750-758. doi: 10.1080/0284186X.2018.1431400. Epub 2018 Feb 1.
Response Evaluation Criteria in Solid Tumours (RECISTs 1.1) define computed tomography (CT) as the gold standard in response evaluation of patients with metastatic colorectal cancer (mCRC) who are undergoing chemotherapy. The aim of this study was to evaluate whether carcinoembryonic antigen (CEA), which is cheaper and easier to perform, can replace repeated CT.
The study included 66 patients with non-resectable mCRC participating in a phase I-II study. CEA values were determined, and CT images were taken every 2 months. CT images were externally and retrospectively reviewed according to the RECIST 1.1 criteria. Different cut-off values for CEA change in percent (DeltaCEA%) compared with baseline or nadir value underwent testing to find patients with disease control (that is stable disease, partial or complete response) at 2, 4, 6 and 8 months, in order to identify those who could have continued with chemotherapy based on CEA values alone. CT verification is needed in progressive disease (PD), and therefore identifying PD patients was our secondary endpoint.
The results showed that by using a cut-off value of 0 for DeltaCEA%, disease control was seen in all patients at all measuring points (negative predictive value (NPV) = 1.0). Secondarily, increasing CEA was able to identify all PD patients (sensitivity (Se) = 1.0) and in 50-74% of the patients increasing CEA provided a lead time to PD on upcoming CT. It was possible to replace CT with CEA in all patients with decreasing CEA, meaning that 23-47% of CT scans could have been avoided at any given time point.
When the CEA level at a certain measuring point is the same or lower than CEA at baseline or at nadir (the measuring point with the lowest CEA value) during treatment, CEA can replace CT.
实体瘤反应评估标准（RECISTs 1.1）将计算机断层扫描（CT）定义为转移性结直肠癌（mCRC）患者接受化疗时评估反应的金标准。本研究旨在评估癌胚抗原（CEA）是否可以替代重复 CT，CEA 更便宜且更容易操作。
本研究纳入了 66 例不可切除的 mCRC 患者，他们参加了一项 I 期- II 期研究。测定 CEA 值，并每 2 个月拍摄 CT 图像。根据 RECIST 1.1 标准对 CT 图像进行外部和回顾性审查。测试了与基线或最低点相比 CEA 变化百分比（DeltaCEA%）的不同截断值，以寻找在 2、4、6 和 8 个月时具有疾病控制（即稳定疾病、部分或完全缓解）的患者，以便仅根据 CEA 值确定哪些患者可以继续接受化疗。在疾病进展（PD）时需要进行 CT 验证，因此识别 PD 患者是我们的次要终点。
结果表明，使用 DeltaCEA%的截断值为 0，所有患者在所有测量点均显示疾病控制（阴性预测值（NPV）= 1.0）。其次，CEA 升高能够识别所有 PD 患者（敏感性（Se）= 1.0），并且在 50-74%的患者中，CEA 升高提供了在即将进行的 CT 上 PD 的提前期。在所有 CEA 下降的患者中，CEA 可以替代 CT，在任何特定时间点都可以避免 23-47%的 CT 扫描。
在治疗过程中，当某一测量点的 CEA 水平与基线或最低点（CEA 值最低的测量点）相同或更低时，CEA 可以替代 CT。
