Endobronchial Ultrasound Improves the Diagnosis of the Tracheobronchial Invasion of Advanced Esophageal Cancer.

BACKGROUND: Accurate diagnosis of the tracheobronchial invasion of advanced esophageal cancer is essential to select appropriate treatment and improve prognosis; however, it is difficult using the conventional modalities. This study aimed to clarify the diagnostic usefulness of convex probe endobronchial ultrasound (CP-EBUS) for the diagnosis of the tracheobronchial invasion of advanced esophageal cancer. METHODS: We conducted a cadaveric study to clarify the changes in ultrasonic and histopathologic findings in the esophageal tumor and tracheal invasion models. Additionally, we examined CP-EBUS for patients with advanced thoracic esophageal cancer in whom tracheobronchial invasion was suspected on contrast-enhanced computed tomography (CE-CT) scan. We retrospectivity evaluated the diagnosis of CP-EBUS, comparing the pathological findings and treatment outcomes. RESULTS: Cadaveric esophageal tumor and tracheal invasion models showed the disappearance of the third layer observed with CP-EBUS and histologically proven interruption of the adventitia. This indicated that the third layer corresponded with the tracheal adventitia. We examined 40 patients with advanced thoracic esophageal cancer in whom tracheobronchial invasion was suspected. The precise diagnosis was pathologically confirmed in 9 of 14 patients diagnosed with cT3 who underwent radical surgery. 20 of 26 cases diagnosed with cT4b received definitive chemoradiotherapy, and 4 cases received salvage surgery and pathologically confirmed precise diagnosis. CONCLUSION: CP-EBUS is extremely useful for diagnosing the tracheobronchial invasion of advanced esophageal cancer. It could be an effective modality for determining treatment strategies in cases with a marginal surgical indication.