CT may help detect some types of colon cancer spread, but not all.
CT can help detect colon cancer tumor invasion beyond the bowel wall, but not so much with detection of nodal involvement, according to a study published in the American Journal of Roentgenology.
Researchers from the Netherlands sought to determine the accuracy of CT in the detection of tumor invasion beyond the bowel wall and nodal involvement of colon carcinomas. "Detecting nodal involvement with CT is unreliable," Elias Nerad, MD, radiologist at Catharina Hospital Eindhoven and researcher at Netherlands Cancer Institute in Amsterdam, said in a release. "The use of thin slices improved the detection of tumor invasion beyond the bowel wall, as well as the detection of malignant lymph nodes, and is therefore advocated. Also, evidence suggests that CT colonography improves the accuracy of CT in the local staging of colon tumors, which could have a major clinical effect if neoadjuvant chemotherapy is adopted in the treatment of colon cancer."
The researchers performed a literature search to identify studies describing the accuracy of CT in the staging of colon carcinomas. Studies including rectal carcinomas that were inseparable from colon carcinomas were excluded. Thirteen studies were identified.
The results showed pooled sensitivity, specificity, and diagnostic odds ratios (ORs) for detection:
|Tumor invasion beyond the bowel wall (T3-T4)||Tumor invasion depth of 5 mm or greater (T3cd–T4)||Nodal involvement (N+)|
|Diagnostic Odds Ratios||20.6||7.8||4.8|
Two studies using CT colonography were included with sensitivity and specificity of 97% and 81%, respectively, for detecting T3–T4 tumors. The researchers wrote that CT had good sensitivity for the detection of T3–T4 tumors, and evidence suggested that CT colonography increases its accuracy. Discriminating between T1–T3ab and T3cd–T4 cancer was challenging, but data were limited.