Sa1212 Interaction Between Esophageal Cancer (EC) Total Length of Disease and Treatment With Either Surgery or Definitive Chemoradiotherapy for Patients With EC

Introduction EC primary tumour length has long been considered important when planning surgical treatment. More recently, the total length of oesophageal disease (including the most distal and most proximal tumour extent or lymph node metastasis) as measured at endoscopic ultrasound (ELoD) has emerged as a strong prognostic indicator. This study aimed to investigate the prognostic importance of the ELoD treatment interaction (ELoD*RxI) with surgery or definitive chemoradiotherapy (dCRT). Methods Six hundred and forty-five (430 male, 215 female) consecutive patients (median age 65 (31-85) yr, 430 male) with esophageal cancer were studied. Three hundred and twenty-three patients underwent surgical resection (155 neoadjuvant chemo, 53 neoadjuvant CRT) and 322 received dCRT. Cox regressionmultivariate analysis was employed in order to identify the independent, significant prognostic indicators. The final model from the multivariate analysis included the variables ELoD and Treatment, thereby allowing the calculation of the relative hazard of death for those receiving surgery and those receiving dCRT according to the ELoD. The hazard ratio of death following surgery versus dCRT was subsequently plotted in relation to increasing ELoD in order to identify a hypothetical ELoD crossover point at which the hazard of death following surgery would become greater than the hazard of death following dCRT. Results Median, 2 year and 5 year survival was 28 months, 57.1% & 34.5% following surgery compared with 22 months, 47.5% & 24.4% following dCRT (Chi2 11.202, df 1, p=0.001). On multivariate analysis the ELoD (HR 1.624, 95%CI 1.146-2.301, p=0.006), Treatment (HR 1.617, 95%CI 1.098-2.380, p=0.015) and the ELoD*Treatment interaction (HR 0.667, 95%CI 0.433-1.027, p=0.066) were included in the final model. The hazard ratios for surgery versus dCRT were calculated according to the ELoD and are shown below (Fig.1) Conclusions EC patients with shorter EloDs are better treated with surgery. Patients with EloDs approaching 12cm may still benefit from surgery or dCRT. However, patients with EloDs over 12cm are arguably better treated with dCRT.