Preoperative staging CT thorax in patients with colorectal cancer: its clinical importance.

Abstract

Recent studies suggest that there is little benefit to routine preoperative staging CT of the thorax in colorectal cancer. The current study hypothesized that staging CT of the thorax is not mandated in all patients with colorectal cancer. This study was a tertiary-care center retrospective observational study. Patients with a diagnosis of colon and rectal adenocarcinoma during 2006 to 2011 were included in a hospital database. Demographic, pathological, radiological, survival, and clinical factors were recorded. Three hundred eighty-two patients were included in the analysis (234 male, 148 female). All patients underwent preoperative staging CT of the thorax to determine the presence of pulmonary metastasis and/or indeterminate lesions. Patients demographics were reviewed, and the factors associated with pulmonary metastasis and indeterminate lesions were evaluated. Distant metastases were evident in 61 patients (16%). CT scans revealed pulmonary metastasis in 23 patients (6%), and indeterminate lesions in 33 (8.6%). Only one-third of pulmonary lesions were evident on chest x-ray. On logistic regression analysis, nodal positivity was associated with an increased risk for pulmonary metastasis (p = 0.03). There was no difference in overall survival between patients with pulmonary metastasis and indeterminate lesions (p = 0.35, Kaplan-Meier estimate, log rank analysis). Pulmonary metastasis developed during postoperative surveillance in 7 patients with indeterminate lesions (21.2%). This is a retrospective, single-center study with a relatively small sample size. Pulmonary metastasis is relatively rare in colorectal cancer, and staging CT of the thorax may not be mandated in low-risk patients.