Tumor and nodal staging of colon cancer: accuracy of preoperative computed tomography at a Swedish high-volume center

When deciding treatment options for patients with colon cancer, accurate staging is required. In Sweden, the main preoperative evaluation modality to determine tumor and nodal stage is computed tomography (CT).

The aim of this study was to investigate how well the preoperative (CT-determined) clinical tumor and nodal stage (cTN) correlated with the postoperative histopathological stage (pTN). Another aim was to validate the tumor and nodal stage data in the Swedish Colorectal Cancer Registry (SCRCR).

The SCRCR was used to identify patients with colon cancer, treated at a Swedish high-volume center during 2013–2016 (n = 974). Data were gathered from medical records regarding cTN and pTN stage, and predefined patient and tumor variables. The agreement between cTN and pTN was analyzed using kappa statistics.

After excluding patients with either pre- or postoperative TN stage missing, 383 patients remained for further analyses. The analyses showed an agreement between cT and pT of κ: 0.27 and between cN and pN of κ: 0.21 (fair agreement). When comparing tumors with low (T1–3; N0) versus high risk (T4; N1–2), the kappa value was 0.19 (slight agreement). When comparing the SCRCR to medical records, 78% of completely staged tumors had been correctly reported.

The agreement between cTN and pTN was low in this study population, indicating a need for enhanced precision of the preoperative staging process. A high frequency of erroneous preoperative staging data in the SCRCR shows the need for further efforts of ensuring correct data transfers into the registry.