The usefulness of preoperative CT in colon cancer staging: impact of radiologists' experience.

PURPOSE: To assess the agreement between radiologists in the detection of specific features related to T- and N-stage and evaluate accuracy in colon cancer staging.

METHODS: Patients who underwent contrast-enhanced computed tomography (CECT) before surgery were enrolled and evaluated by three radiologists with different experience. Pathological data were used as the reference standard. Tumor location, presence of tumor bulging, fat stranding, lateroconal fascia invasion, enlarged vessels, axial short diameter of the biggest node, shape, enhancement pattern, intranodal necrosis, and cluster were collected. Reliability analysis was performed with κ statistics and intraclass correlation coefficients (ICCs). Logistic regressions were used to determine independent predictors associated with staging.

RESULTS: Seventy five patients were evaluated. The reliability analysis was moderate to substantial for tumor location (κ = 0.853), T staging (κ = 0.531), tumor bulging (κ = 0.478), fat stranding (κ = 0.490), lateroconal fascia invasion (κ = 0.436), enlarged vessels (κ = 0.401), the axial short diameter of the biggest node (ICC = 0.732), shape (κ = 0.484), enhancement pattern (κ = 0.431), intranodal necrosis (κ = 0.606), and cluster (κ = 0.358). For all readers, sensitivity was higher for T3 lesions (60-69%) and specificity was higher for T2 and T4 lesions (84.5-90.0% and 82.4-85.1%). The diagnostic accuracy was acceptable for all lesions and among all readers (50.7-92.1%). The lateroconal fascia invasion and enlarged vessels resulted as independent predictor factors (OR = 3.292 and OR = 2.651) for T staging, while nodes' cluster and dimension as independent predictor factors of N staging [OR = 3.798 and OR = 1.083].

CONCLUSION: Reader's experience is one of the most important factors associated with the correct classification of colon cancer. Moreover, CECT can help depict radiological features independently associated with the T and N stages.