Perioperative chemotherapy versus preoperative chemoradiation therapy in gastroesophageal adenocarcinomas: Real-life data from a Canadian academic oncology center.

405 Background: Perioperative chemotherapy is a standard of care (SOC) for patients with resectable gastroesophageal junction adenocarcinoma (GEA), with FLOT as the reference regimen therapy. Preoperative chemoradiotherapy (CRT), another SOC also showed survival improvement compared to surgery alone. The recent ESOPEC trial showed the superiority of FLOT compared to CRT in both esophageal and gastroesophageal junction adenocarcinomas. Nonetheless, few studies have directly compared these two therapeutic approaches. The CHUM (Centre Hospitalier de l’Universite de Montreal) is a tertiary referral center for the management of these patients. Methods: From Jan 2011 to Dec 2024, 660 pts were operated at the CHUM for esophageal and GEJ adenocarcinoma. We retrospectively reviewed the clinical and pathological characteristics of patients who have received perioperative FLOT or CRT (per CROSS protocol). We report preliminary real-life data of 161 patients using Kaplan-Meier survival curves to compare the overall survival (OS) and disease-free survival (DFS), and pathological complete response (pCR) rates between these two populations using OR. Results: As of September 2025, the data of 161 patients (79 FLOT, 82 CROSS) have been analyzed. More than 80% were male patients. Median age was 65 years and comparable between 2 groups. In the CROSS group 97.5% had Siewert I/II and 2.5% Siewert III. In the FLOT group Siewert III represented 24.4%. Most patients in both groups had a T3 clinical stage (94,9% in FLOT vs 92,6% in CROSS) and a positive nodal status (71.8 vs 71.6%). Median DFS was 36.0 months in the FLOT arm (95% confidence interval CI, 24.0 months to not-reached), as compared to 19.5 months in the CROSS group (95% CI, 13.0 to 38.0 months). Median OS was 81.7 months in the FLOT arm (95% CI, 36.1 months to not-reached) and 36.0 months in the CROSS group (95% CI, 22.0 to 60.0 months). pCR was noted in 12.8% of FLOT patients and 19.8% of CROSS patients. Conclusions: Our results showed that perioperative treatment with FLOT confers better DFS and OS as compared to CROSS. More patient data as well as additional subgroup analyses are currently underway.