Clinical staging of esophageal carcinoma. CT, EUS, and PET

CT is readily available to all patients. It is relatively inexpensive and fees are usually reimbursed. It provides exquisite anatomic detail of the chest and abdomen in patients with esophageal cancer. The only reliable use of CT in the determination of T is the exclusion of T4 tumors, which is suggested by the preservation of fat planes. Enlarged lymph nodes are suspicious for metastatic disease but require further study or tissue sampling if nodal metastases will determine treatment. Its major use is in the detection of distant metastatic disease; however, 30% to 60% of distant metastases may be radiographically occult. There is a significant learning curve for EUS staging of esophageal cancer. It is suggested that this study be performed at institutions where there is a dedicated, experienced endoscopic ultrasonographer with adequate instrumentation that allows specialty imaging and EUS-FNA. EUS is the best means of clinically determining T. The addition of EUS-FNA to routine EUS evaluation of lymph nodes allows an accuracy similar to the EUS determination of T. EUS has no purpose in assessment of non-nodal distant metastatic disease; however, the serendipitous finding of distant metastases in adjacent structures visualized during the evaluation of the primary tumor and lymph nodes has, on occasion, detected M1b disease. FDG-PET represents an advance over CT scanning in the screening for distant metastases. The major problems with FDG-PET staging of esophageal cancer is failure to detect metastatic deposits less than 1 cm in diameter and lack of anatomic definition. It is unable to determine T and has been inaccurate in the detection of lymph node metastases. Because this test is not readily available, is expensive, and is not routinely reimbursed, its use in staging esophageal cancer continues to be limited. Today, CT and EUS are the mainstays in the clinical staging of esophageal carcinoma. When possible, FDG-PET should be added to CT to improve the evaluation of non-nodal M1b disease. Results of these studies should determine the necessity for invasive staging techniques and direct their use.