CT staging of colorectal cancer: what do you find in the chest?

Abstract

Aim: To clarify the chest computed tomography (CT) findings in patients with a new diagnosis of colorectal adenocarcinoma.

Materials and methods: Patients diagnosed with colorectal cancer (CRC) over a 3-year period were retrospectively studied. All CT examinations were performed within a single NHS Trust using the same CT system and protocol. Two primary outcomes were assessed: the presence of pulmonary metastases and the identification of a significant, unexpected chest abnormality.

Results: Five hundred and fourteen out of 568 (90.5%) CRC patients underwent complete CT staging. Thirty-one patients (6%) had lung metastases, of which four (0.8%) were isolated. Three hundred and fifty-three (68.7%) had no evidence of pulmonary metastases, but 130 (25.3%) had indeterminate lung nodules (ILNs). The ILNs of 12 patients were subsequently confirmed as metastases on follow-up. A major non-metastatic finding (pulmonary embolism or synchronous primary malignancy) was found in 15/514 patients (3%).

Conclusions: Thoracic CT altered the initial TNM stage in fewer than 1% of CRC patients, but the detection of significant incidental chest disease and the establishment of an imaging baseline are useful outcomes of this imaging strategy. One-quarter of all staging examinations demonstrated ILNs.