The median PFS differed significantly between patients with high and low AUC0–24h of 5-FU (5.40 vs. 3.70 m, P = 0.022, Fig. 3a), and the median TTF differed borderline between patients with high and low AUC0–24h of 5-FU (4.13 vs. 3.10 m, P = 0.054, Fig. 3b).Fig. 3 a Kaplan–Meier curve of progression-free survival according to AUC0–24h of 5-FU and b the Kaplan–Meier curve of time to failure according to AUC0–24h of 5-FU. AUC areas under the curve