Association between postoperative nutritional status and time to initiation of adjuvant chemotherapy in gastrointestinal cancers: a restricted cubic spline analysis.

PURPOSE: To explore the relationship between early postoperative nutritional status and time-to-chemotherapy (TTC) in gastrointestinal cancer patients and provide a reference for nutritional intervention and reasonable chemotherapy arrangements. METHODS: This study enrolled consecutive patients who underwent radical gastrointestinal cancer surgery with planned adjuvant chemotherapy at a tertiary hospital in Dalian, China (June 2023-June 2025). Nutritional indicators included BMI, NRS-2002 score, and serum albumin concentration and their associations with TTC were analyzed using restricted cubic splines (RCS) and multivariable regression models. RESULTS: RCS analysis revealed an approximately linear dose-response relationship between the NRS-2002 score and TTC. Based on multivariate regression, each 1-point increase prolonged TTC by 2.36 days and conferred a 57% higher risk of chemotherapy delay. Conversely, BMI and serum ALB levels exhibited nonlinear associations with TTC (U-shaped and inverted L-shaped, respectively). Exploratory inflection points derived from RCS were BMI ≥ 23.82 kg/m2 and serum albumin ≥38.37 g/L. Multivariable-adjusted associations suggested that patients above these inflection points tended to have a 4-day shorter TTC, with a 42% reduction in chemotherapy-delay risk (BMI only). CONCLUSION: Postoperative nutritional indicators are closely related to TTC. The inflection point values of BMI and serum albumin derived from this study are hypothesis-generating findings and should not be regarded as validated clinical targets for routine clinical application. Targeted nutritional management may help optimize chemotherapy timing and guide clinical nursing work.