The Usefulness of FDG-PET/CT for the Prediction of Regional Lymph Node Metastases in Colorectal Cancer

ABSTRACT

PURPOSE: Proper preoperative staging is important in planning optimal therapy for individual patients and improving outcome. There is no ideal imaging methods for accurate colorectal cancer staging. The purpose of our study was to determine the usefulness of fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) for the status of regional lymph node metastasis in colorectal cancer. METHODS: Two hundred forty six surgically resected colorectal cancers were retrospectively reviewed from Jan 2007 to Jul 2009. All patients underwent abdominal CT and FDG-PET/CT preoperatively. RESULTS: There were 129 males (52.4%) and the mean age was 62 (range 25~88 years). Tumor location was the colon in 148 (59.7%) patients, and the rectum in 98 (40.3%) patients. Pathological stages were I 43 (17.5%), II 78 (31.7%), III 81 (32.9%), IV 44 (17.9%). Regional lymph node metastasis by pathological examination was 118 (48%) patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of regional lymph node staging were 66.4%, 66.7%, 64.8%, 68.3%, and 67%, respectively, with the FDG-PET/CT, and 57.1%, 71.3%, 64.8%, 64.3%, and 65%, respectively, with whole abdominal CT. The difference in the accuracy of nodal staging between the two modalities was not significant. CONCLUSION: The diagnostic accuracy of FDG-PET/CT for the assessment of regional lymph node metastasis in colorectal cancer was relatively low, and similar to that of abdominal CT. Therefore, further study will be needed to determine the clinical usefulness of preoperative FDG-PET/CT in colorectal cancer.