Perioperative Nutritional Changes Predict Adjuvant S-1 Dose Intensity in Resectable Pancreatic Cancer.

BACKGROUND/AIM: Maintaining treatment intensity is important during adjuvant S-1 chemotherapy for resectable pancreatic cancer; however, factors associated with reduced relative dose intensity (RDI) during adjuvant chemotherapy (AC) remain unclear. This study investigated the association between perioperative inflammatory and nutritional indices and the RDI of S-1 during AC. PATIENTS AND METHODS: This retrospective single-center study included 69 patients with resectable pancreatic cancer who underwent adjuvant S-1 chemotherapy following neoadjuvant chemotherapy (NAC) and pancreatectomy between November 2019 and February 2025. Patients were classified according to AC S-1 RDI (≥80% vs. <80%). Inflammatory and nutritional indices, as well as changes in prognostic nutritional index (PNI) and geriatric nutritional risk index (GNRI) from NAC initiation to AC initiation, were compared between the groups. RESULTS: AC S-1 RDI was significantly associated with overall survival and recurrence-free survival (both p=0.02), and patients with RDI ≥80% had significantly better overall survival than those with RDI <80% (p=0.02). At AC initiation, PNI and GNRI were significantly higher in the RDI ≥80% group than in the RDI <80% group. Changes in PNI and GNRI from NAC initiation to AC initiation were also more favorable in the RDI ≥80% group. On multivariate analysis, these nutritional indices were associated with maintenance of RDI ≥80% for S-1 as AC. Receiver operating characteristic analysis showed that GNRI at AC initiation had the highest predictive performance for reduced AC S-1 RDI (<80%) (area under the curve = 0.77; optimal cut-off of 98.7). CONCLUSION: Nutritional status at AC initiation and perioperative changes in nutritional status were associated with maintenance of AC S-1 RDI in patients with resectable pancreatic cancer. The GNRI at AC initiation may be useful for assessing the risk of reduced S-1 RDI during AC.