Colorectal Cancer: Open Access

Comparison of Contrast Enhanced MDCT and Integrated FDG PET/CT Staging of Colorectal Cancer

Introduction: To compare contrast enhanced multidetector computed tomography (CEMDCT) with positron emission tomography/computed tomography (PET/CT) in staging of primary colorectal carcinoma. Methods: This was an institute review board approved prospective study done over a period of 18 months. 15 patients of histologically proven colorectal carcinoma on endoscopy were included. Scanning was performed in 3D mode on an integrated PET/ CT system. Initially, CEMDCT was performed from head to mid thigh. Following this, PET scan was acquired. Pre-operative TNM staging was done by both PET/CT and CEMDCT scans. The findings were correlated with the operative and histopathological findings which were considered standards of reference, and used for calculating the accuracy. All patients underwent surgery and histopathological staging was obtained. One patient had 2 synchronous malignant lesions. Hence, a total of 16 colorectal cancers were evaluated.
Results: The overall diagnostic accuracy for tumor, node and metastasis (TNM) staging on CEMDCT was 68.75%, 50% and 87.5% for primary tumor, regional lymph node, and distant metastasis, respectively. The overall diagnostic accuracy for TNM staging on PET/CT was 87.5%, 31.25% and 87.5% for primary tumor, regional lymph node, and distant metastasis, respectively. A higher accuracy of primary tumor staging was seen with PET/CT while accuracy for detection of distant metastasis was same with both modalities. On CEMDCT M0 stage had one false negative while no false negative seen on PET/CT. Accuracy for regional lymph node staging was poor with both modalities, although it was better with CEMDCT. There was slight agreement between the CEMDCT and PET/CT with Kendal l’s tau-b test showing value of 0.403. ‘p’ value was 0.052, suggesting not a significant relationship level. Kappa value was 0.162 which shows that there was a poor strength of agreement.
Conclusion: In view of higher accuracy of primary tumor staging, PET/CT can be considered as a first line investigation for preoperative evaluation of patients with colorectal cancer.

Author(s):

Manavjit S Sandhu, Divya Singh, Naveen Kalra, Anmol Bhatia, Anish Bhattacharya, Rajesh Gupta and Niranjan Khandelwal

Abstract | Full-Text | PDF

Share this