Consistency of Radiological Staging in Resectable Mismatch-Repair Proficient Colon Cancer: An Interobserver Agreement Study

Year: 2026

Type: article

Abstract: Background Reproducibility and accuracy of radiological staging with CT imaging is crucial for selecting patients with resectable, non-metastatic colon cancer (CC) who may benefit from neoadjuvant strategies. Methods We evaluated interobserver agreement among four independent radiology equipes in staging patients with resectable, non-metastatic, mismatch repair proficient CC with available preoperative CT imaging. Radiology equipes were blinded to clinical and pathological data, and categorized tumors according to FOxTROT/OPTICAL and Node-RADS criteria, classifying T (T1/2, T3, T4, including stratification by extramural invasion [EMI]) and N status. The primary endpoint was interobserver agreement (Cohen's κw); secondary endpoints included concordance with pathological staging and diagnostic performance metrics. Bayesian and cross-validation analyses assessed robustness. Results Among 109 patients (32% pT2, 34% pT3, 34% pT4; 46% pN0/1c, 54% pN1–2), overall interobserver agreement indicated inadequate concordance for both cT (κw = 0.56; 95% CI, 0.43–0.68) and cN category (κw = 0.51; 95% CI, 0.36–0.66). Of 109 patients, 38 (35%) were staged identically for T stage by all four Radiology groups, while 71 (65%) showed some disagreement. When considering risk stratification into high risk (cT3 with EMI ≥5 or cT4) versus low risk (cT1/cT2 or cT3 with EMI <5) 56 patients (51%) received the same classification from all four groups, and 95 patients (87%) were classified consistently by at least three groups. Overall concordance between radiology and pathological staging was inadequate for both T (κw=0.47; 95%CI: 0.35-0.57) and N staging (κw=0.16; 95%CI: 0-0.33). The mean sensitivity and specificity of CT scan for pT3/T4 and pT4 were 72%/78% and 33%/93%. Conclusions Identification of high-risk features in resectable CC by CT scan should be implemented to guide patients' selection for neoadjuvant therapies. Micro abstract This study assessed interobserver agreement among four radiology teams in staging resectable colon cancer using preoperative CT imaging. With 109 patients, results showed poor concordance in radiological T and N staging (κw = 0.56 and 0.51). When considering risk stratification, 87% of patients were classified consistently by 3 out of four groups. These findings highlight the need for improved radiology-pathology correlation, particularly for high-risk features such as pT4 tumors and node positivity.

Source: Clinical Colorectal Cancer

DOI: 10.1016/j.clcc.2026.01.007

Institutions: Fondazione IRCCS Istituto Nazionale dei Tumori, Istituto Oncologico Veneto, Azienda Socio Sanitaria Territoriale Grande Ospedale Metropolitano Niguarda, University of Pisa, University of Turin, Azienda Ospedaliera Universitaria Pisana, IFOM, Candiolo Cancer Institute

Language: English

Topic: Colorectal Cancer Surgical Treatments

Subfield: Oncology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,690

Funder: Ministero dell'Istruzione e del Merito

Award: G1560786584

OpenAlex ID: W7128088239