Accuracy of Staging in Superficial Esophageal Carcinoma Using Endoscopic Ultrasonography with Sonoprobe, Focusing on the Muscularis Mucosa

Abstract

Objective: The depth of invasion of superficial esophageal carcinoma is closely linked to the appropriate therapy. Endoscopic ultrasound (EUS) with thin ultrasound probe provides the images of the degree of tumor invasion. We use interruption of the muscularis mucosa (MM) as a parameter for diagnosing the depth of submucosal invasion by EUS with sonoprobe at higher frequency of 30 MHz. This study investigated the precise diagnosis rate and the limitations of diagnosing the depth of invasion by visualizing interruption of the MM on EUS. Subjects and Methods: Among 104 patients with superficial esophageal carcinoma investigated from March 2000 to October 2004, 112 lesions were enrolled and evaluated histologically to assess the depth of invasion. For diagnosing the depth of invasion by EUS, a small soft balloon with an effective length of 1 cm was used, as well as a 30 MHz probe from Olympus. Results: The MM was visualized in 103/112 lesions (92%). The correct diagnosis rate for mucosal carcinoma and submucosal carcinoma was 88.4 and 78.3%, respectively. When the correct diagnosis rate was assessed for the subclassifications of depth of invasion, it was 74, 56, and 68% for M1-2, M3-SM1, and SM2-3, respectively. When the incorrect diagnostic cases were assessed for them, those were 36 cases, with 28 (78%) being underdiagnosed and the remaining 8 (22%) being over diagnosed. The factors involved were fibrosis, lymphoid hyperplasia, or microinvasion of the SM layer, while compression by the balloon was the cause in only 5 cases. Conclusion: A visualization rate of 92% for the MM can be achieved by the present technique using a small soft balloon. So the diagnosis of the depth of invasion by EUS with sonoprobe can assess the distinguishing between mucosal tumors and submucosal tumors. However, it is more difficult for M3-SM1 cases to diagnose precisely because of microinvasion and lymphoid hyperplasia, suggesting that the resolution of the equipment needs to be improved. Objective: The depth of invasion of superficial esophageal carcinoma is closely linked to the appropriate therapy. Endoscopic ultrasound (EUS) with thin ultrasound probe provides the images of the degree of tumor invasion. We use interruption of the muscularis mucosa (MM) as a parameter for diagnosing the depth of submucosal invasion by EUS with sonoprobe at higher frequency of 30 MHz. This study investigated the precise diagnosis rate and the limitations of diagnosing the depth of invasion by visualizing interruption of the MM on EUS. Subjects and Methods: Among 104 patients with superficial esophageal carcinoma investigated from March 2000 to October 2004, 112 lesions were enrolled and evaluated histologically to assess the depth of invasion. For diagnosing the depth of invasion by EUS, a small soft balloon with an effective length of 1 cm was used, as well as a 30 MHz probe from Olympus. Results: The MM was visualized in 103/112 lesions (92%). The correct diagnosis rate for mucosal carcinoma and submucosal carcinoma was 88.4 and 78.3%, respectively. When the correct diagnosis rate was assessed for the subclassifications of depth of invasion, it was 74, 56, and 68% for M1-2, M3-SM1, and SM2-3, respectively. When the incorrect diagnostic cases were assessed for them, those were 36 cases, with 28 (78%) being underdiagnosed and the remaining 8 (22%) being over diagnosed. The factors involved were fibrosis, lymphoid hyperplasia, or microinvasion of the SM layer, while compression by the balloon was the cause in only 5 cases. Conclusion: A visualization rate of 92% for the MM can be achieved by the present technique using a small soft balloon. So the diagnosis of the depth of invasion by EUS with sonoprobe can assess the distinguishing between mucosal tumors and submucosal tumors. However, it is more difficult for M3-SM1 cases to diagnose precisely because of microinvasion and lymphoid hyperplasia, suggesting that the resolution of the equipment needs to be improved.