A PET-Derived SUVmax-to-Albumin Ratio Predicts Recurrence After Neoadjuvant FLOT in Gastric Cancer

Background and Objectives: Although perioperative FLOT improves outcomes in locally advanced gastric cancer, postoperative recurrence remains frequent. This study evaluated the prognostic value of a PET-derived SUVmax/albumin ratio integrating tumor metabolism and nutritional status in patients treated with neoadjuvant FLOT. Materials and Methods: This retrospective single-center study included patients with gastric adenocarcinoma treated with neoadjuvant FLOT followed by curative gastrectomy between January 2017 and May 2025, using data obtained from existing medical records after ethical approval. Pre-treatment SUVmax from ¹⁸F-FDG PET/CT and serum albumin were recorded to calculate the SUVmax/albumin ratio. Progression-free survival (PFS) was the primary endpoint. Prognostic factors were analyzed using Cox regression, and discriminatory performance was assessed using receiver operating characteristic (ROC) analysis. Results: A total of 104 patients were included. During a median follow-up of 28 months (IQR, 16–46 months), 46 patients (44.2%) developed recurrence. Patients with recurrence had significantly lower serum albumin levels and higher PET SUVmax values and PET SUVmax/albumin ratios (all p < 0.001). In multivariable analysis, the PET SUVmax/albumin ratio remained significantly associated with PFS (HR 1.71; 95% CI 1.33–2.21; p < 0.001). ROC analysis demonstrated moderate discriminatory performance (AUC 0.733; 95% CI 0.638–0.815), while additional time-dependent ROC analyses yielded AUC values of 0.732 (95% CI 0.611–0.836) at 1 year and 0.829 (95% CI 0.694–0.947) at 3 years. Exploratory comparative analyses demonstrated that both PET SUVmax and serum albumin retained statistical significance when evaluated simultaneously in the same multivariable model. Conclusions: The pre-treatment PET SUVmax/albumin ratio was significantly associated with PFS in patients with gastric cancer treated with neoadjuvant FLOT and may represent an exploratory composite prognostic biomarker requiring further prospective validation.