Preoperative staging of resectability of colon cancer using virtual colonoscopy: correlation with surgical results. Our experience.

Purpose: To evaluate the clinical usefulness of preoperative computed tomography colonography (CTC) in locoregional staging in patients with abdominal pain secondary toocclusive colorectal cancer (CRC).

Materials And Methods: 80 patients with abdominal pain underwent CTC initially without contrast and after diagnosis with contrast. 47 patients had distal CRC and 33 had proximal CRC. CTimages were analyzed independently by two radiologists, using MPR reconstruction and VR images. Depending on the anatomical depth of wall invasion primary tumor (T) was classified ≤ T2, T3 and T4. The definition of node disease (N) was based on the number of involved regional lymph nodes. Metastases (M) were characterized by the presence and location of distant disease. Pre treatment stage (cT cN) was compared with pathologic stage (pT pN). Accuracy of CTC was also evaluated.

Results: The overall accuracy values for T staging of reviewer 1, reviewer 2 and consensus reading were 91.6%, 86.2% and 92.8% respectively; 92.2%, 79.8% and 92.5% for T2; 88.1%, 85.5%, and 89.7% for T3; and 94.5%, 93.5% and 96.2% for T4. The accuracy values for N staging and M staging were 81,.8%, 94.0% for reviewer 1; 78.2% and 88.1% for reviewer 2; 81.8% and 94.0% for consensus reading, respectively.

Conclusion: In our experience CTC is not only useful in the evaluation of the proximal bowel, but can also provide surgeons with accurate information about staging and tumor localization. CTC is recommended for better evaluation of preoperative staging.

Key Words: CT colonography, Colorectal cancer, Extracolonic findings, Staging.