Preoperative staging of colorectal cancer using virtual colonoscopy: correlation with surgical results.

OBJECTIVE: The aim of this study was to evaluate the clinical usefulness of computed tomography colonography (CTC) in the preoperative staging in patients with abdominal pain for occlusive colorectal cancer (CRC) and to compare the results of CTC with the surgical ones.

PATIENTS AND METHODS: 127 patients with abdominal pain, iron deficiency anemia and occlusive CRC underwent a CTC examination in prone position without intravenous contrast agent and in prone position after administration of intravenous contrast medium. All the patients underwent surgery after CTC. Two radiologists with different experience analyzed the images first independently and then by consensus. They evaluated the location of the lesion, the depth of the invasion of the colon-rectal wall (T stage), lymph node involvement (N stage) and the presence or absence of distant metastasis (M stage). CTC findings were correlated with surgical outcomes.

RESULTS: The overall accuracy values for tumour localization according to consensus reading of CTC examinations in comparison to surgical results were 100% (K = 1, p = 0.0001). The overall accuracy values of agreement for T staging of reader 1, reader 2 and consensus reading of CTC examinations in comparison to surgical results were respectively 95.5% (K = 0.876, p = 0.0035), 93.3% (K = 0.858, p = 0.0037) and 97.7% (K = 0.926, p = 0.0014) for ≤ T2; 91.3% (K = 0.839, p = 0.0027), 88.3% (K = 0.817, p = 0.0031), and 92.9% (K = 0.894, p = 0.0025) for T3; 89.6% (K = 0.825, p = 0.0037), 86.2% (K = 0.837, p = 0.0032) and 89.6% (K = 0.821, p = 0.0023) for T4. The overall accuracy values for N staging for reader 1, reader 2 and consensus reading was 90.2% (K = 0.865, p = 0.0029). The overall accuracy values for M staging of reader 1, reader 2 and consensus reading was 92% (K = 0.875, p = 0.0019).

CONCLUSIONS: CTC with is a very useful tool for accurate pre-treatment staging and localization of occlusive CRC.