Because both the number and location of metastatic lymph nodes and the N stage influence survival in esophageal cancer, accurate noninvasive evaluation of individual lymph node groups for the presence of metastasis is essential for therapeutic planning. Therefore, we investigated the accuracy of FDG PET for evaluating individual lymph groups in esophageal cancer patients and compared the results with those of CT and endoscopic sonography (ES).
Methods: Sixty-one consecutive patients with histologically proven primary esophageal carcinoma were studied prospectively with FDG PET. Thirteen patients who were treated nonsurgically were excluded from data analysis. The remaining 48 patients underwent esophagectomy and lymph node dissection. All 48 patients underwent CT scanning, including the lower neck, thorax, and upper abdomen, with intravenous administration of contrast medium. ES was performed in 45 of the patients but was incomplete in 12 patients because of esophageal stenosis. The accuracies of FDG PET, CT, and ES were compared with histologic findings.
Results: During surgery, a total of 382 lymph node groups were dissected in 48 patients, of which 100 node groups in 32 patients were malignant on histologic examination. For assessing metastasis to individual groups, FDG PET showed 57% sensitivity, 97% specificity, and 86% accuracy, whereas CT showed 18% sensitivity (P < 0.0001), 99% specificity (P = 0.033), and 78% accuracy (P = 0.003). For N staging, FDG PET was correct in 83% (40/48) of the patients, whereas CT and ES were correct in 60% (29/48; P = 0.006) and 58% (26/45; P = 0.003), respectively.
Conclusion: FDG PET is more accurate than is CT or ES for evaluating metastasis to individual lymph node groups and for N staging in esophageal cancer and thus may be helpful in determining the therapeutic plan.