P22 Postoperative and pathological outcomes of CROSS and FLOT as neo-adjuvant therapy for oesophageal and junctional adenocarcinoma: an international cohort study from the Oesophagogastric Anastomosis Audit (OGAA)

Abstract Introduction Ongoing debate exists around optimum approach to locally advanced esophageal adenocarcinoma (EAC), with proponents for perioperative chemotherapy, such as FLOT, or multimodal therapy, in particular the CROSS regimen. This study aimed to compare the postoperative and pathological outcomes between CROSS and FLOT in esophageal adenocarcinoma (EAC) patients from an international, multicenter cohort. Methods Patients undergoing CROSS (n=350) and FLOT (n=368), followed by curative esophagectomy for EAC were identified from the Oesophagogastric Anastomosis Audit (OGAA). Results The 90-day mortality was higher after CROSS than FLOT (5% vs 1%, p=0.005), even on adjusted analyses (odds ratio (OR): 3.97, CI95%: 1.34–13.67). Postoperative mortality in CROSS were related to higher pulmonary (74% vs 60%) and cardiac complications (42% vs 20%) compared to FLOT. CROSS was associated with higher pCR rates (18% vs 10%, p=0.004) and margin-negative resections (93% vs 76%, p<0.001) compared with FLOT. On adjusted analyses, CROSS was associated with higher pCR rates (OR: 2.05, CI95%: 1.26–3.34) and margin-negative resections (OR: 4.55, CI95%: 2.70–7.69) compared to FLOT. Conclusion This study provides real-world data CROSS was associated with higher 90-day mortality than FLOT, related to cardio-pulmonary complications with CROSS. These warrant a further review into causes and mechanisms in selected patients, and at minimum suggest the need for strict radiation therapy quality assurance. Research into impact of higher pCR rates and R0 resections with CROSS compared to FLOT on long term survival is needed.