The key prognostic factor which predicts outcome after esophagectomy for cancer is the number of malignant lymph node metastases, but data regarding the accuracy of endoscopic ultrasound (EUS) in determining and predicting the metastatic lymph node count preoperatively are limited. The aim of this study was to assess the prognostic significance of EUS defined lymph node metastasis count (eLNMC) in patients diagnosed with esophageal cancer. Two hundred and sixty-seven consecutive patients (median age 63 years, 187 months) underwent specialist EUS followed by stage directed multidisciplinary treatment (183 esophagectomy [64 neoadjuvant chemotherapy, 19 neoadjuvant chemoradiotherapy], 79 definitive chemoradiotherapy, and 5 palliative therapy). The eLNMC was subdivided into four groups (0, 1, 2 to 4, >4) and the primary measure of outcome was survival. Survival was related to EUS tumor (T) stage (P < 0.0001), EUS node (N) stage (P < 0.0001), EUS tumor length (p < 0.0001), and eLNMC (P < 0.0001). Multivariable analysis revealed EUS tumor length (hazard ratio [HR] 1.071, 95% CI 1.008-1.138, P= 0.027) and eLNMC (HR 1.302, 95% CI 1.133-1.496, P= 0.0001) to be significantly and independently associated with survival. Median and 2-year survival for patients with 0, 1, 2-4, and >4 lymph node metastases were: 44 months and 71%, 36 months and 59%, 24 months and 50%, and 17 months and 32%, respectively. The total number of EUS defined lymph node metastases was an important and significant prognostic indicator.

In this study, EDTV based on total EUS-defined length of disease emerged as a new and important prognostic indicator for patients with esophageal cancer.

4558 Background: TNM histopathological staging system for esophageal cancer is controversial, and will soon be revised to account for the relative burden of the number of lymph node metastases. The aim of this study was to assess the prognostic significance of endoluminal ultrasound (EUS) defined lymph node metastasis count (eLNMC) in patients with esophageal cancer. Methods: Two hundred and sixty-seven consecutive patients (median age 63 yr, 187 m) underwent EUS followed by stage directed multidisciplinary treatment [183 esophagectomy (92 neoadjuvant chemotherapy), 79 definitive chemoradiotherapy, and 5 palliative therapy]. The eLMNC was subdivided into four groups (0, 1, 2 to 4, >4) and the primary measure of outcome was survival. Results: Survival was related to EUS T stage (p<0.0001), EUS N stage (p<0.0001), EUS tumour length (p<0.0001), and the eLNMC (p<0.0001). Multivariable analysis revealed EUS tumour length (HR 1.071, 95% CI 1.008 to 1.138, p=0.027) and eLNMC (HR 1.302, 95% CI 1.133 to 1.496, p<0.0001) to be significantly and independently associated with survival. Median and 2 year survival for patients with 0, 1, 2 to 4, and >4 lymph node metastases were: 44 months and 71%; 36 months and 59%; 24 months and 50%; and 17 months and 32% respectively. Conclusions: The eLNMC was an important and significant prognostic indicator in patients with esophageal cancer, which should in future be reported and used to revise the perceived radiological stage, in order to inform stage directed multimodal therapy. No significant financial relationships to disclose.

e15519 Background: The aim of this study was to assess the prognostic significance of endoluminal ultrasound defined tumour volume (EDTV) in patients diagnosed with esophageal cancer. The hypothesis was that tumour volume is a better predictor of outcome than tumour length. Methods: One hundred and seventy-four consecutive patients (median age 64y, 128 m) underwent both CT and specialist EUS, and the maximum potential tumour cylinder volume (EDTV) was calculated using the formula πr2L (cylinder volume), where r = tumour thickness (cm) and L = total length of disease, including the position and level of both the primary tumour and proximal and distal lymph nodes (cm). All patients received stage directed multidisciplinary treatment [surgery 104 patients (80 neoadjuvant chemotherapy), definitive chemoradiotherapy 54 patients, and palliative therapy alone 16 patients]. The primary measure of outcome was survival. Results: Survival was related to EUS T (p=0.013), EUS N (p=0.001), EUS M1a stage (p=0.004), EUS disease length (p=0.001), and EDTV (all patients <25cm3, p=0.001, surgical patients <40cm3, p=0.036). Forward conditional multivariate analysis revealed 3 factors to be associated with survival; EUS N stage (HR= 1.646, 95% CI 1.041 to 2.602, p=0.033), EUS M1a stage (HR= 2.702, 95% CI 1.069 to 6.830, p=0.036), and EDTV (HR= 2.702, 95% CI 1.069 to 6.830, p=0.025). Conclusions: EDTV emerged as a new and important prognostic indicator for patients diagnosed with esophageal cancer. No significant financial relationships to disclose.