Staging of esophageal cancer by endoscopic ultrasonography: emphasis on n staging

Zeynab Yaberi mohammad,1,* Amir hasanvand,2

1. Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
2. Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Abstract

Introduction

Endoscopic ultrasonography (eus) plays an important role in the management of patients with esophageal cancer. the treatment and prognosis of patients with esophageal cancer are highly stage-dependent, and accurate initial staging is essential to selection of the appropriate therapy for patients. the primary role of eus is in the initial triage of patients to receive neoadjuvant therapy or to undergo surgical resection directly, or, in very early-stage disease, to undergo endoscopic mucosal resection (emr).

Methods

Publications were retrieved by a systematic search of multiple bibliographic databases, including medline, embase, scopus, cochrane library, web of science, biomed central, science direct, and google scholar. the language of search was restricted to english.

Results

Eus has repeatedly been shown to be superior to other imaging modalities for locoregional staging, especially for peritumoral lymph node evaluation, and to have the additional capability to procure tissue via fine-needle aspiration (fna) if needed. esophageal cancer is treated based on the tumor–node–metastases (tnm) classification issued by the american joint committee on cancer (ajcc). the most recent revision of the ajcc tnm classification was issued in 2010 and features several important changes, reflecting advancements in our understanding of the biology of esophageal cancer. these include a refined definition of esophageal versus gastric cancer, a shift in emphasis to number of involved lymph nodes over the location of involved lymph nodes, and a separate staging for squamous cell carcinoma and adenocarcinoma, which better reflects stage-dependent differences in survival between the two histologic subtypes. the n-stage of esophageal cancer is determined by the number of lymph nodes involved, and carries significant prognostic implications. because of the rich supply of lymphatic vessels within the esophageal wall, including superfacial regions such as the lamina propria and submucosa, lymph node involvement in esophageal cancer is common, and occurs early. up to 30% of patients with submucosal involvement of their tumor will have positive lymph node metastasis at time of presentation. it has been shown that the prognosis in patients with nodal involvement is significantly worse than in those without nodal disease. certain features seen on eus can be helpful in distinguishing benign from malignant lymph nodes. malignant lymph nodes tend to be bigger than 1 cm (in short axis), round, sharply demarcated, and hypoechoic. additionally, the more of these features present, the higher the likelihood of the lymph node being malignant.

Conclusion

Modified eus criteria have been proposed that may further improve the diagnostic predictive value of lymph node involvement on eus examination. these include the finding of more than lymph nodes, celiac lymph node presence, and t-stage 3 or 4, in addition to the four standard criteria. eus has been shown to be superior to ct scan for the n-staging of esophageal cancer. the sensitivity of eus in detecting positive lymph nodes in esophageal cancer ranges from 56 to 97%.

Keywords

Endoscopic ultrasonography, esophageal cancer, n staging.