Additional value of PET/CT over PET in assessment of locoregional lymph nodes in thoracic esophageal squamous cell cancer.

The aim of this study was to compare the value of reviewing combined 18F-FDG PET/CT images with that of reviewing side-by-side PET and CT images in the diagnosis of locoregional lymph node metastases in patients with esophageal squamous cell cancer. METHODS: From November 2003 to December 2005, 45 patients with thoracic esophageal squamous cell cancer underwent 18F-FDG PET/CT before surgery. The results of reviewing combined PET/CT images and side-by-side PET and CT images for the diagnosis of locoregional lymph node metastases were compared prospectively in relation to pathologic findings. RESULTS: All patients underwent successful surgery, and pathologic examination confirmed nodes positive for metastasis in 32 patients and 82 of 397 excised nodal groups. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PET/CT were 93.90% (77/82 nodal groups), 92.06% (290/315), 92.44% (367/397), 75.49% (77/102), and 98.31% (290/295), respectively, whereas those of PET were 81.71% (67/82), 87.30% (275/315), 86.15% (342/397), 62.62% (67/107), and 94.83% (275/290), respectively. P values were 0.032, 0.067, 0.006, 0.063, and 0.037, respectively. The differences in sensitivity, accuracy, and negative predictive value between PET and PET/CT were statistically significant. CONCLUSION: PET/CT improves the sensitivity, accuracy, and negative predictive value of 18F-FDG imaging in the assessment of locoregional lymph nodes in thoracic esophageal squamous cell cancer and provides data of diagnostic significance.