Pathological response guides adjuvant 5-fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) chemotherapy in surgically resected gastro-oesophageal cancer (SPACE-FLOT): international cohort study

Abstract Background Many patients with locally advanced gastro-oesophageal cancers are unable to complete adjuvant 5-fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) chemotherapy, raising questions about its therapeutic utility. The aim of this study was to examine whether pathological response to neoadjuvant FLOT can guide its adjuvant use. Methods Patients with non-metastatic gastro-oesophageal adenocarcinoma who received neoadjuvant FLOT and underwent surgery from 1 January 2017 to 1 January 2022 from 43 hospitals across 12 countries were analysed. Pathological response was assessed using tumour regression grading systems, trichotomized into minimal responders (MR; worst category), complete responders (CR; pCR), and partial responders (PR; between MR and CR). Survival outcomes of patients who did and did not receive adjuvant FLOT were compared using Kaplan–Meier, Cox regression, propensity score matched, and sensitivity analysis. Results A total of 1887 patients (459 MR, 221 CR, and 1207 PR) were evaluated. The median follow-up was 25.5 (interquartile range 15.0–39.1) months. In the MR group, there was no difference in disease-free survival (DFS; HR 1.03 (95% c.i. 0.78 to 1.36), P = 0.836) between those who did and did not receive adjuvant FLOT. Whilst there was a difference in non-adjusted OS, this became statistically non-significant after adjusting for baseline characteristics (HR 0.96 (95% c.i. 0.70 to 1.30), P = 0.801). In the CR group, there was no difference in DFS (HR 0.88 (95% c.i. 0.41 to 1.85), P = 0.724) or OS (HR 0.69 (95% c.i. 0.31 to 1.54), P = 0.343) between those who did and did not receive adjuvant FLOT. In the PR group, adjuvant FLOT conferred a significant DFS (HR 0.68 (95% c.i. 0.55 to 0.86), P < 0.001) and OS (HR 0.55 (95% c.i. 0.44 to 0.69), P < 0.001) benefit. Conclusion Pathological response to neoadjuvant FLOT may guide the use of adjuvant FLOT, enabling personalized approaches to treatment.