Is 3 weeks a proper time point for the diagnosis of grade B POPF after pancreaticoduodenectomy?

In 2016, the International Study Group of Pancreatic Fistula (ISGPF) improved the definition of postoperative pancreatic fistula (POPF) which defines one of diagnostic criteria for progression of biochemical leak (BL) to grade B fistula as drain for more than 3 weeks. However, we found patients with BL after pancreaticoduodenectomy (PD) or laparoscopic pancreatoduodenectomy (LPD) in our medical center usually progressed to grade B fistula within 3 weeks, which is inconsistent with diagnostic criteria (more than 3 weeks) described in the guidelines. The objective of this study was to investigate the time point at which patients with BL progressed to grade B fistula after PD or LPD. We selected patients from June 2013 to October 2022 as the research subjects. We used a receiver operating characteristic (ROC) curve to calculate the cutoff value of the time point when BL progressed to grade B fistula. The cutoff value of the time point at which BL progresses to grade B fistula was postoperative day (POD) 9.5. The sensitivity and specificity were 63.6% and 81.4%, respectively. The cutoff value of time point of BL progression to grade B fistula was 9.5, which indicated that we do not need to define grade B fistula as drain for more than 3 weeks. We considered that a too-late time point might delay the timely diagnosis and treatment of grade B fistula and further optimization of the definition of grade B fistula was necessary.