Total neoadjuvant chemotherapy with FLOT for resectable gastric and gastroesophageal junction adenocarcinoma: Real-world outcomes from a Chilean oncology institution.

Abstract

e15720 Background: Perioperative FLOT improves survival and pathological complete response (pCR) in resectable gastric cancer; however, postoperative chemotherapy completion remains suboptimal due to toxicity. Delivering all 8 cycles of FLOT chemotherapy preoperatively as total neoadjuvant therapy (TNT) may improve adherence and oncologic outcomes. We report safety, pathological response, and survival outcomes from a large Chilean real-world cohort treated with total neoadjuvant chemotherapy FLOT. Methods: We performed a retrospective cohort study of patients with resectable, locally advanced gastric or gastroesophageal junction adenocarcinoma (cT1–4 N+ or cT3–4 N0, M0) treated at Instituto Oncologico Fundacion Arturo Lopez Perez, Santiago, Chile, between May 2019 and December 2024. All patients were planned to receive eight cycles of neoadjuvant FLOT chemotherapy prior to surgery. Clinical, pathological, and treatment-related variables were collected from institutional databases and medical records. Survival outcomes were estimated using the Kaplan–Meier method. Results: Ninety-one patients were included. Mean age was 58 years; 67% were male and 88% had ECOG performance status 0–1. 40.7% were diffusive pattern (signet ring cell). 74.8% patients were cT3-4 and 78% were cN+. The median number of administered FLOT cycles was 8. Grade ≥3 treatment-related adverse events occurred in 21.7%, most commonly gastrointestinal toxicity and neutropenia. Dose reductions were required in 41.8%, and permanent treatment discontinuation occurred in 17.6%. Most patients underwent total gastrectomy (76.9%) with D2 lymphadenectomy (94.5%). R0 resection was achieved in 97.8%. Pathological complete response was observed in 18.7%. 22% and 50.5% achieved ypT0 and ypN0 status respectively. The median follow-up was 43.8 months. 36-month overall survival was 78.2% and disease-free survival was 73.7%. Recurrence occurred in 22%, predominantly at distant sites such as peritoneal and liver metastases. Conclusions: Total neoadjuvant FLOT demonstrated acceptable toxicity, high complete response, R0 resection, and nodal clearance rates, and encouraging long-term survival in a real-world Chilean population. These findings support total neoadjuvant FLOT as a feasible and effective strategy for resectable gastric and gastroesophageal junction adenocarcinoma.