ABSTRACT
PURPOSE: The most common site of metastases in colorectal cancer (CRC) is the liver, and the second common site is the lung (10-20%). Preoperative staging for CRC is very important. The aim of this study was to assess the usefulness of chest computed tomography (CT) for preoperative staging in CRC. METHODS: From January 2006 to December 2007, a total of 597 patients with colorectal cancer underwent surgery at our hospital. One hundred fifty of those patients had received chest CT preoperatively. We analyzed the chest radiologic findings from chest x-ray (CXR), abdominal CT, and chest CT. RESULTS: The detection rate of abnormal lung findings was higher in chest CT than in the other chest radiologic findings (chest PA: 10 [6.6%]; abdominal CT: 19 [12.7%]; chest CT: 48 [32.0%]). On the chest CT, 19 of the 150 (12.7%) patients that had received a chest CT preoperatively were initially suspected of having malignant lesions. Besides two primary lung malignancies (solitary nodules), metastatic lesions were revealed in 5 (3.3%), 11 (7.3%), and 17 (11.3%) patients on CXR, abdominal CT, and chest CT, respectively. Eleven (64.7%) of the patients having metastatic chest CT lesions were also identified on lower lung fields by abdominal CT. Seven also had other metastatic foci (liver and paraaortic LN). Initially, stage IV was identified in 37 (24.7%) and 40 (26.7%) patients in abdominal CT and chest CT, respectively. After one year, 11 of the 150 (7.3%) patients who had received a chest CT had been diagnosed with pulmonary metastasis. CONCLUSION: Chest computed tomography is the most sensitive method for the diagnosis of pulmonary metastases. However, if the interpretations of abdominal CT and individualized diagnostic methods are accurate, the demand for unnecessary preoperative work-up may be reduced.