Chest Computed Tomography Screening in Colorectal Cancer Patients

Abstract

We read with interest the article ‘‘Clinical usefulness of chest radiography in detection of pulmonary metastases after curative resection for colorectal cancer’’ that was published in the July 2007 issue of World Journal of Surgery [1]. In a retrospective analysis of patients after curative resection for colorectal cancer, the authors showed that the sensitivity of abdominal computed tomography (CT) with lower thorax images was superior to chest radiography for lung metastasis detection. They concluded that elevating the upper level of the scan during abdominal CT or performing chest CT could result in higher detection of lung metastases. As Lee et al. noted, reports evaluating CT versus radiography for detecting pulmonary metastases in the context of colorectal cancer have been few and somewhat inconsistent [2, 3]. In our center, we did a prospective study in a selected subset of 96 patients undergoing preoperative evaluation for liver metastases resection, 90% of which were from colorectal cancer, with intrapatient comparison of chest radiography and whole-chest CT for the detection of lung metastases. Neoplastic confirmation of lung lesions was done either by lung biopsy or evidence of growth on follow-up. Lung metastases were present in 13 patients (13.5%). Chest CT was more sensitive than radiography and alone prevented unnecessary liver surgery in three patients (3.1%) in whom chest radiography was normal. Four other chest CT-positive/chest radiography-negative patients were not operated on based on the nonresectability of liver lesions demonstrated by abdominal CT. In six patients, lung metastases were demonstrated by both chest CT and radiography. Incidental CT visualization of indeterminate small lung nodules (too small for characterization with biopsy or positron emission tomography) remains a potential drawback of routine chest CT for colorectal cancer in a small number of patients. Those patients require follow-up chest CT [4]. Since our prospective study, we have included chest CT in the preoperative evaluation of our patients for colorectal liver metastases resection. This is especially valuable with the wider indications of surgical resection of liver metastases allowed by the use of improved combination chemotherapy regimens [5].