Integrated Prognostic Stratification After Perioperative FLOT in Gastric and Gastroesophageal Junction Adenocarcinoma: A Multicenter Real-World Study

Background/Objectives: Outcomes after perioperative FLOT for gastric and gastroesophageal junction adenocarcinoma remain variable, even among patients treated with curative intent. Although postoperative pathological findings are central to risk assessment, they do not fully capture patient-related factors that may influence recovery, treatment completion, and survival. This multicenter study evaluated routinely available clinical, laboratory, and pathological variables and assessed whether integrating these variables could improve postoperative prognostic stratification. Methods: We retrospectively analyzed 173 patients with locally advanced gastric or gastroesophageal junction adenocarcinoma treated with perioperative FLOT across seven oncology centers in Türkiye. Overall survival (OS) was the primary endpoint. Baseline inflammatory/nutritional status, pretreatment carcinoembryonic antigen (CEA), postoperative nodal status, and comorbidity burden were assessed. An exploratory modified FLOT Prognostic Score (mFPS) was constructed by assigning one point each for high inflammatory/nutritional risk, elevated CEA, ypN-positive disease, and age-adjusted Charlson Comorbidity Index ≥ 5. Results: At a median follow-up of 39.7 months, median OS was 41.4 months, with estimated 2-year and 5-year OS rates of 69% and 44%, respectively. Surgery was performed in 164 patients, and 83 patients completed planned adjuvant chemotherapy. In multivariable analysis, ypN-positive disease, higher comorbidity burden, and high inflammatory/nutritional risk were independently associated with shorter OS. Among the 126 patients with complete data available for all score components, the mFPS stratified patients into groups with significantly different outcomes: median overall survival was not reached in the low-risk group, compared with 56.1 months in the intermediate-risk group and 18.7 months in the high-risk group. Conclusions: Survival after perioperative FLOT was not determined by residual disease burden alone. Integrating postoperative nodal status with baseline host-related factors may help identify patients at increased risk of adverse outcomes following curative-intent treatment. The proposed score should be considered exploratory and requires external validation before clinical application.