Staging of Esophageal Cancer Using High-Frequency Ultrasound (HFUS)

Abstract

Purpose: Standard echoendoscopic evaluation of superficial esophageal tumors using frequencies of 7.5MHz and 12MHz has limited ability to optimally visualize the mucosal and submucosal layers. High-frequency catheter-based miniprobes operating at 20MHz permit improved imaging of the superficial layers of the esophagus. The diagnostic accuracy of HFUS staging in superficial esophageal tumors has not been definitively established. The aim of this study was to assess our institution's staging accuracy for superficial esophageal cancers using HFUS, and to determine whether the use of HFUS improves patient management. Methods: Between December 1999 and December 2004, 42 patients with esophageal cancer underwent preoperative EUS staging without neoadjuvant chemoradiotherapy. Within this group, five patients underwent staging with HFUS, and make up the study subset. Two patients were referred for Barrett's esophagus with high-grade dysplasia (HGD) on prior endoscopic biopsy, and three patients were referred for Barrett's esophagus with esophageal nodules found to be at least intramucosal adenocarcinoma on prior endoscopic biopsy. Overall staging accuracy, rate of complications, and impact on clinical management were assessed. Results: Four of the five patients (80%) had technically adequate HFUS imaging. By surgical pathology, all four patients had T1 disease (confined to the mucosa or submucosa). The accuracy of HFUS T staging in this group was 100% (95% CI 40–98%). No complications occurred as a result of HFUS examination. In both patients referred with HGD in the setting of Barrett's esophagus, demonstration of at least intramucosal adenocarcinoma changed management, prompting esophagectomy instead of endoscopic ablation with photodynamic therapy. Conclusions: 1. Use of HFUS at 20MHz frequency appears to be highly accurate in T staging of superficial esophageal cancers. However, larger studies will now be needed to confirm these results. 2. Use of HFUS appears to be safe. 3. HFUS staging has the potential to significantly impact patient management, particularly in its ability to detect intramucosal or more deeply invasive adenocarcinoma in patients with Barrett's esophagus with known HGD.