556. PREDICTORS OF EARLY RECURRENCE AFTER OESOPHAGECTOMY AND NEOADJUVANT FLOT

Abstract Background FLOT, a novel type of perioperative chemotherapy, has led to improved survival after surgery for oesophageal adenocarcinoma. Yet, rates of cancer recurrence remain high. There is limited research on predictors for early recurrence (ER) in patients receiving FLOT. The aim of this study was to investigate ER and survival rates and identify risk factors of ER. Methods Patients who underwent neoadjuvant FLOT and oesophagectomy for oesophageal and oesophagogastric junction adenocarcinomas at a single high-volume centre between August 2018 and January 2023 were evaluated for ER, defined as disease present within one year of surgery. Multivariable logistic regression was conducted to identify risk factors for ER. Patients who died in-hospital or within 90 days of surgery and those with positive longitudinal margin were excluded. Results 145 patients were included. 139 (95.9%) and 63 (43.4%) patients fully completed neoadjuvant and adjuvant FLOT. 44 patients (30.3%) developed recurrence and 22 patients (15.2%) had ER in the follow up period. Distant, local or mixed type of recurrence was found in 32, 6 and 6 patients respectively. The estimated recurrence free survival and overall survival at one, two and three years were 81.4%, 66.9%, 52.0% and 89.0%, 73.7%, 65.5% respectively. The estimated median survival after recurrence was 4.9 months. In multivariable analysis ypN3 status was identified to be an independent predictor of ER (OR 13.769, 95%CI 1.358-139.573, p=0.026). Conclusions This study confirms that ER after neoadjuvant FLOT is common. Patients with a high pathological nodal stage are particularly at risk. It is possible that some patients with ER might have undetected metastases prior to surgery and some do not respond well to neoadjuvant treatment. Identifying chemotherapy non-responders is an important area for future research. These results might be beneficial for prognostication and tailoring follow up care, such as regular surveillance imaging, treatment, and frequency of reviews.