Endoscopic ultrasound in the pre-therapeutic staging of gastroesophageal adenocarcinoma: the diagnostic value in defining patients eligible for a neoadjuvant chemotherapy regimen

Introduction: Neoadjuvant chemotherapy regimens have been proven to decrease tumour size and stage and significantly improve progression-free and overall survival in the treatment of locoregional advanced gastroesophageal adenocarcinomas. Therefore, the pre-therapeutic staging of the tumour extension is of utmost importance for stratification of patients into this individualized therapy regimen. Within the last years most experience has been gained using endoscopic ultrasound (EUS) and it has been considered as a valuable tool for the assessment of locoregional disease.
Aim: To evaluate the accuracy of endoscopic ultrasound for the preoperative staging of locally advanced gastroesophageal adenocarcinomas with regard to defining patients’ eligibility for neoadjuvant chemotherapy.
Material and methods: Between January 2006 and June 2007 consecutive patients (n = 47) who underwent resection of a gastroesophageal adenocarcinoma and would have been potentially eligible for neoadjuvant chemotherapy were included in this study. Preoperative EUS staging was compared to the postoperative histopathology results. Furthermore, the specificity, sensitivity and positive and negative predictive values for serosal invasion and/or lymph node positivity as an eligibility criterion for neoadjuvant chemotherapy were evaluated.
Results: Thirty-seven patients were included in the analysis with adenocarcinomas of the distal oesophagus (n = 7), the oesophagogastric junction (n = 8) and the stomach (n = 22). The overall accuracy for predicting the T stage was 64.9% (n = 24) with an over- and understaging of 13.5% (n = 5) and 21.6% (n = 8), respectively. The overall accuracy for predicting the N stage was 64.7% (n = 22), with an over- and understaging of 26.5% (n = 9) and 8.8% (n = 3). Twenty-five out of 37 patients would have met the eligibility criteria for enrolment in a neoadjuvant chemotherapy regimen. The sensitivity was 76% (n = 19/25). The specificity was 75% (n = 9/12). The positive predictive value was 86.4%. The negative predictive value was 60%.
Conclusions: In this series the sensitivity and specificity of EUS for identification of patients eligible for neoadjuvant chemotherapy seem acceptable. Especially the positive predictive value, which expresses the probability that a patient identified by EUS as eligible for neoadjuvant chemotherapy met the corresponding histopathological criteria, was high (86.4%). Therefore, it seems justified to apply neoadjuvant chemotherapy in patients identified as eligible by EUS. This underpins the importance of EUS in the staging of gastroesophageal carcinoma. In patients with a “negative” EUS result, the staging needs to be complemented by additional diagnostic modalities such as CT, PET or laparoscopy to facilitate the correct identification of patients who meet the histopathological inclusion criteria for neoadjuvant chemotherapy.