55 Impact of Staging Investigations on Nodal Upstaging in Early Oesophago-Gastric Adenocarcinoma: Multi-Centre CONGRESS Dataset Analysis

Abstract Aim Current recommendations for the clinical staging of patients undergoing resection for early oesophago-gastric (OG) cancer are variable and the value of staging investigations is unclear. The aim of this study was to assess current practice for staging early OG cancers across the UK, and the accuracy of staging with reference to nodal disease at surgery. Method Data for surgical patients was extracted from the CONGRESS database, a large UK-based multi-centre dataset for patients with T1N0 OG cancer between 2015 and 2022. Logistic regression analysis was performed to assess the association of different staging investigations on subsequent nodal upstaging. Cox regression analysis was used to analyse for impact on overall survival (OS). Results 497 patients from 28 centres were included, 13.1% of which underwent N upstaging from clinical to pathological staging. The rate of unexpected LNM was 12.7% in patients who underwent a CT pre-treatment, compared to 18.2% in patients with no staging investigations. Patients that underwent no staging investigations were also more likely to have unexpected nodal metastases at surgery (OR 6.66 (95%CI 1.34-33.24), p=0.021). The addition of PET-CT, EUS and staging laparoscopy had no significant impact on N upstaging (p=0.062, 0.053, and 0.690 respectively). No combination of staging modality had a significant impact on OS. Conclusions Current guidelines are variable in their recommendation of pre-operative staging investigations for early OG cancer. This study suggests CT plays an important role in the staging of this population. Other staging modalities could be considered selectively, rather than routinely, to preserve resources and accelerate treatment pathways.