Usefulness of Chest CT in Colorectal Cancer Staging

Purpose: The lung represents the second most metastatic site after the liver in colorectal cancer (CRC). Traditionally, pulmonary metastasis has been evaluated by means of a chest X-ray. But, recently, chest computed tomography (CT) is increasingly being performed to detect pulmonary metastasis in CRC. This study was performed to evaluate the usefulness of chest CT over chest X-ray for early detection of pulmonary metastasis in preoperative staging in CRC. Methods: We retrospectively reviewed 108 cases of CRC patients surgically treated with a curative intent at Chonbuk National University Hospital from April, 2007 to December, 2007. All evaluated by both chest X-ray and chest CT preoperatively. Results: Five among 108 patients had metastatic lesions of the lung. Four of these 5 patients (80%) had a positive chest CT. But one of these 5 patients (20%) had a positive chest X-ray. Chest CT provided a sensitivity of 80% and a positive predictive value of 80% for the detection of metastatic lesions of the lung. In contrast, chest X-ray provided a sensitivity of 20% and a positive predictive value of 50% for the detection of metastatic lesion of the lung. Nine of these 108 patients (8%) were diagnosed with solitary pulmonary nodule (SPN) and one of them was confirmed to have metastatic lesion of the lung. Conclusion: There are isolated metastatic lung lesions without other organ involvement in CRC (4.6%). Chest CT is a more accurate imaging modality for detection of pulmonary metastasis in CRC. Also, we should carefully follow-up SPN detected by preoperative chest CT.