OGC SO22 - Accuracy of CT and FDG/PET clinical staging within a dedicated multidisciplinary service for patients with oesophago-gastric cancer

Abstract Background Accurate staging for oesophago-gastric cancer is important in ensuring correct treatment pathways, avoiding unnecessary surgery and providing prognostication for patients. Previously, cross sectional imaging in accurately providing tumour (T) and nodal (N) staging has been variable for upper GI malignancies, with usage of invasive investigations such as EUS to provide more specific local staging. With the increased utilisation of specialist multidisciplinary involvement and improved technology, we aimed to assess whether CT and PET imaging may be able to provide sufficiently accurate staging required for treatment decision making. Method All patients who underwent oesoophagogastric resections between January 2022 and March 2024 were identified from our surgical database. Patients were included if they had oesophago-gastric cancer, and underwent curative resection without neo-adjuvant treatment. Data collected included age, gender, location of primary tumour, CT/PET staging, and final histology. Outcomes assessed included rate of understaging in clinical and pathological T and N staging, and sensitivity and specificity of imaging in identifying presence of nodal disease. Results 38 patients were included in this analysis. For oesophageal and GOJ cancers, T stage under-reporting occurred in 6/27 (22%) patients, and N under-reporting in 7/27 (27%) patients. Radiological staging correlated with final pathological staging in 55% of T staging and 59% of N staging. Sensitivity (55.56%, 95% CI 21-86%) and specificity (72.2%, 95% CI 46.5-90.3%) for nodal disease on CT/PET was low, however no tumour or nodal under-staging would have impacted management. Gastric cancer staging accuracy assessment was limited by small numbers (n=12), however T under-staging occurred in 5/12 (42%) patients and N under-staging occurred in 5/11 patients (45%). Conclusion Involvement of dedicated radiology services in multidisciplinary care for oesophago-gastric cancer provides adequate radiological staging to guide treatment. Gastric cancer clinical staging requires laparoscopic and endoscopic assessment for accurate tumour assessment and management guidance. Radiological under-staging is less common in oesophageal and GOJ tumours than gastric cancer and has minimal impact on patient management.