Diagnostic Value of FDG-PET/CT for Lymph Node Metastasis of Colorectal Cancer

Background Lymph node metastasis is an important prognostic factor in patients with colorectal cancer. We assessed the ability of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) to diagnose lymph node metastases in colorectal cancer patients. Methods We retrospectively analyzed the records of 473 patients who underwent preoperative FDG-PET/CT, followed by curative surgery for colorectal cancer. Lymph node metastases were assessed as proximal or distal, depending on their anatomical location. We analyzed the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FDG-PET/CT and CT for detecting lymph node metastases. Results In detecting proximal lymph nodes, FDG-PET/CT had a sensitivity of 66 %, a specificity of 60 %, a PPV of 63 %, an NPV of 62 %, and an accuracy of 63 %; whereas CT had a sensitivity of 87 %, a specificity of 29 %, a PPV of 57 %, an NPV of 68 %, and an accuracy of 59 % ( P = 0.245). FDG-PET/CT and CT also showed similar accuracy in detecting distal lymph nodes (87 vs. 88 %, P = 0.620). Conclusion Preoperative FDG-PET/CT and CT have comparable accuracy in detecting lymph node metastases of colorectal cancer.