[Value of multislice spiral CT in preoperative staging of rectal carcinoma].

BACKGROUND & OBJECTIVE: Preoperative staging is important for optimal therapy planning and prognosis prediction of rectal carcinoma. The role of conventional computed tomography (CT) in preoperative staging of rectal carcinoma is controversial. This study was to evaluate the value of multislice spiral computed tomography (MSCT) in preoperative staging of rectal carcinoma.

METHODS

From Mar. 2006 to Feb. 2007, 87 patients with pathologically proved rectal cancer underwent preoperative plain and enhanced MSCT. Two radiologists evaluated independently tumor location, size, the depth of tumor invasion into the rectal wall (T), the involvement of regional lymph nodes (N) and the presence of distant metastases (M) on CT images. TNM staging was made according to CT findings and compared with the pathologic results. The accuracy, sensitivity, and specificity were assessed.

RESULTS

All the 87 cases of rectal carcinoma were detected clearly by MSCT. The accuracy was 81.6% for TNM staging, 94.3% for T staging, 82.8% for N staging, and 98.9% for M staging. The sensitivity was 90.5% for T1-2 staging, 91.3% for T3 staging, and 97.7% for T4 staging. The specificity was 98.5% for T1-2 staging, 94.2% for T3 staging, and 97.7% for T4 staging. The sensitivity was 92.9% for N0 staging, 72.0% for N1 staging, and 82.4% for N2 staging. The specificity was 88.9% for N0 staging, 88.5% for N1 staging, and 91.7% for N2 staging. Only 1 case of distant metastasis was missed due to the liver lesion of less than 5 mm.

CONCLUSION

MSCT is an accurate technique for preoperative staging of rectal carcinoma, which can assess the extension to adjacent tissues and the presence of lymph node and distant metastases exactly.