Endoscopic ultrasonography in the diagnosis, staging and follow-up of esophageal and gastric cancer.

The accumulating data show that endoscopic ultrasonography (EUS) is highly compatible with the UICC/AJCC staging classification for esophageal and gastric cancer, based on the TNM system expressing anatomical extent of disease. The great strength of EUS in staging these cancers is its ability to image the gut wall and adjacent structures in unique detail. EUS is more accurate than computed tomography in staging the depth of primary tumor invasion (T) and regional lymph node metastases (N). High frequency EUS is not useful in staging for distant metastases (M) due to limited depth of the field. EUS also has limitations in reliably distinguishing between neoplastic and inflammatory tissue. Thus, the major use of EUS is in staging rather than in diagnosis. However, initial reports indicate that EUS may be helpful in the detection of malignancy in Barrett's esophagus, in diagnosing post-operative recurrent cancer, and in evaluating the response to non-operative therapy. EUS appears to represent an important advance in the staging and follow-up of patients with esophageal and gastric cancer. Instruments and techniques will continue to evolve, but the next level of research should be designed to show that the improved staging provided by EUS has clinical utility and can affect patient outcome.