Geriatric Nutritional Risk Index Predicts Tolerability of S-1 as Adjuvant Chemotherapy for Pancreatic Ductal Adenocarcinoma

Objectives: Surgery plus adjuvant chemotherapy (AC) for resectable pancreatic ductal adenocarcinoma (PDAC) has been shown to prolong survival compared with surgery alone. Thus, it is of clinical importance that these patients receive a continuous dose of S-1. The aim of this study was to examine whether the geriatric nutritional risk index (GNRI) is a predictor for the completion of S-1 as AC for PDAC. Methods: Seventy-seven patients who were administered S-1 as AC after pancreatectomy for PDAC between January 2010 and October 2021 were retrospectively enrolled. Predictive markers were statistically analyzed for S-1 completion, which was defined as continued oral administration with relative dose intensity of >80%. Results: Patients were divided into the S-1 complete group (n = 55; 71.4%) and S-1 incomplete group (n = 22; 28.6%). There was a significant association of higher GNRI (P = 0.013) at the onset of AC with the completion of S-1. Receiver operating characteristic curve analysis revealed 94.4 as the optimal cutoff value of GNRI for predicting the completion of S-1. Univariate and multivariate analyses confirmed that GNRI >94.4 was independently associated with the completion of S-1 (P = 0.007). Conclusions: High GNRI value is a predictive marker for the completion of S-1 as AC for PDAC.