Perioperative FLOT in gastric cancer: Effect on survival among East Asian patients in a Canadian population-based cohort.

Abstract

419 Background: The FLOT regimen has emerged as the standard perioperative chemotherapy for resectable gastric and gastroesophageal junction (GEJ) adenocarcinomas. Outcomes in clinical trials differ between Asian and Western populations, with Asian cohorts often achieving superior survival. British Columbia (BC), Canada, provides a unique setting to study this effect given its high proportion of residents of East Asian ancestry. Methods: We conducted a retrospective cohort study of patients with gastric or GEJ adenocarcinoma treated with perioperative FLOT between February 2022 and November 2024 in BC. BC Cancer is the sole provider of publicly funded cancer treatments in the province, and patients were identified using our pharmacy database. Demographic, tumor, safety, and survival data were collected from electronic medical records. Descriptive statistics summarized baseline characteristics. Recurrence-free survival (RFS) and overall survival (OS) were estimated using Kaplan–Meier methods and compared by log-rank tests. Hazard ratios (HRs) with 95% confidence intervals (CIs) were derived from Cox proportional hazards models. Results: Among 141 patients, 40 (28.4%) were East Asian and 101 (71.6%) were of other ethnicities. Median age was 66 (East Asian) vs 64 (Other). ECOG 0–1 was predominant in both groups (85% East Asian, 94% Other). CPS >1 were more common in Asian patients (91.6% vs 72%). Rates of completing all eight cycles of FLOT were similar (40% vs 44%). R0 resection was achieved in 94.7% of East Asian and 82.1% of non-Asian patients. Pathological complete response occurred in 5% of the cohort. Severe FLOT-related toxicity was comparable between groups (16% East Asian vs 23% Other). RFS did not differ significantly by ethnicity (HR 0.77, 95% CI, 0.42–1.42; p=0.40). However, overall survival (OS) favored East Asian patients (median NR vs 40.0 mo; HR 0.46, 95% CI, 0.25–0.87; p=0.016). One- and two-year OS were 90.0% (95%CI, 81.2–99.8) and 82.5% (95%CI, 71.5–95.2) East Asian vs 81.2% (95%CI, 73.9–89.2) and 60.2% (95%CI, 51.4–70.6) non-Asian. Conclusions: East Asian patients treated with perioperative FLOT experienced significantly longer overall survival compared with non-Asian patients, despite similar treatment exposure and toxicity. These findings build up on the data suggesting that asian ethnicity may influence outcomes in gastric and gastroesophageal junction cancer.