Prognostic nutritional index is an independent risk factor for continuing S-1 adjuvant chemotherapy in patients with pancreatic cancer who received neoadjuvant chemotherapy and surgical resection

Reports on the association of perioperative nutritional and inflammatory status with the clinical course of adjuvant chemotherapy did not include neoadjuvant chemotherapy. We aimed to clarify the mechanism by which perioperative nutritional and inflammatory status affect the clinical course of postoperative adjuvant chemotherapy in patients with pancreatic cancer. We enrolled 123 patients with pancreatic cancer retrospectively who underwent surgical resection with neoadjuvant and S-1 adjuvant chemotherapy between January 2013 and December 2022. The duration of continuing S-1 treatment and the continuation rates at 3 and 6 months after initiating adjuvant chemotherapy were calculated using the Kaplan-Meier method. The log-rank test was used to evaluate statistical differences between the high and low prognostic nutritional index (PNI) groups. Univariable and multivariable analyses were performed to determine the risk factors for continuing S-1 adjuvant chemotherapy. The optimal cut-off value for preoperative PNI was 45. Preoperative PNI was an independent risk factor for continuing S-1 adjuvant chemotherapy in patients who underwent perioperative adjuvant chemotherapy and surgical resection (hazard ratio = 2.435, 95% confidence interval = 1.229 - 4.824, p = 0.011). Low PNI was associated with lower S-1completion (p = 0.02) and higher S-1 withdrawal (p = 0.031). Additionally, the preoperative PNI status affected ≥ grade 2 adverse events caused by adjuvant chemotherapy (p