Comparative analysis of colorectal carcinoma staging using operative, histopathology and computed tomography findings

The staging of colorectal carcinoma using 3 modalities viz operative, histopathology and CT scan has been subject of interest in accurately defining the extent of disease. This retrospective as well as prospective study was carried out at CMC, Ludhiana, Punjab from November 2011 to May 2014.

The objective of this study was to assess the usefulness and accuracy of CT scan findings to state the extent and spread of colorectal malignancy and to correlate these findings with histopathological diagnosis.

A total of 31 biopsy proven patients showing variable bowel wall thickening involving the colon /rectum on CECT (Contrast Enhanced Computed Tomography) were included in the study. The tumours were staged based on the CT scan findings and were compared with the operative and histopathological findings.

Rectum was the most common site of involvement followed by the recto-sigmoid involvement. Metastasis was observed in 5 cases out of the 31 malignant cases. Five of the 7 cases were correctly staged as T1 & T2 lesions on CT having a sensitivity of 83.3%, specificity of 92%, and positive predictive value of 71.4% and a negative predictive value of 95.8% in the diagnosis of T1 and T2 lesions. 15 of the 16 cases were correctly staged as T3 lesions. CT had a sensitivity of 88.2%, specificity of 93.8%, and positive predictive value of 93.8% and a negative predictive value of 86.7% in the diagnosis of T3 lesions. All the 8 cases were correctly staged as T4 lesions. CT had a sensitivity of 100%, specificity of 100%, and positive predictive value of 100% and a negative predictive value of 100% in the diagnosis of T4 lesions.

We conclude that CT scan is an excellent modality in diagnosing malignant lesions of the colon and rectum.