Preoperative staging of esophageal carcinoma: miniprobe sonography versus conventional endoscopic ultrasound in a prospective histopathologically verified study.

BACKGROUND AND STUDY AIMS: Endosonographic staging of esophageal carcinoma may be limited by non-traversable tumor stenoses. Dilation of malignant esophageal strictures carries a significant risk of esophageal perforation. We therefore evaluated the use of ultrasonic miniprobes in the staging of stenotic esophageal carcinoma compared with conventional endoscopic ultrasound. PATIENTS AND METHODS: In a blinded, prospective study, which included histopathological evaluation, 53 consecutive patients (43 male, 10 female, mean age 61 years) with stenosing esophageal carcinomas were examined preoperatively. Endosonography was done using the optical GF-UM3 echo endoscope. If tumor strictures were not traversable with this instrument, a blind esophagoprobe, the MH-908 was used for endosonography. Miniprobe sonography (MPS) was done during esophagoscopy in all patients. The various imaging modalities were assessed in terms of complete tumor traversability and correct tumor staging. Every patient underwent surgical tumor resection.
RESULTS: MPS of the esophagus and proximal parts of the stomach was possible in all 53 patients without prior dilation of tumor stenoses. Endosonography with the GF-UM3 instrument was precluded in 23 patients (43.4%) while in 20 of the latter patients the MH 908 esophagoprobe could be passed through tumor stenoses. The overall accuracy rates for depth of tumor infiltration (T) staging were: 62% (31/50) for endosonography (GF-UM3 plus esophagoprobe) and 86.8% (46/53) for MPS. The accuracy rates for T staging in tumors traversable both with the GF-UM3 echo endoscope and with miniprobes were 56.7% (17/30) for GF-UM3 and 80% (24/30) for MPS. The accuracy rates for T staging in tumors traversable only with the MH-908 esophagoprobe and with miniprobes were 70% (14/20) for the MH-908 and 95% (19/20) for MPS. With regard to the presence or absence of peri-esophageal metastatic lymph nodes (N staging), the accuracy rates were 83% (25/30) for MPS and 70% (21/30) for the GF-UM3, and 80% (16/20) for MPS and 70% (14/20) for the MH-908.
CONCLUSION: Compared with conventional endosonography using 7.5-MHz large diameter instruments, MPS enables: a) safe passage through high-grade malignant esophageal strictures, achieving b) higher accuracy rates for T staging, and c) similar rates for N staging. The use of MPS can also represent an improvement in the comfort and safety of patients. Moreover, miniprobe sonography is highly cost-effective compared with conventional endosonography. Thus, MPS appears to be a valuable addition to the armamentarium for staging esophageal carcinoma.