LAUSR

BACKGROUND AND AIMS Identification and resection of successful targets, i.e., T1 N0M0 pancreatic ductal adenocarcinoma (PDAC) and high-grade precursors during surveillance of high-risk individuals (HRIs) confers improved survival. Late-stage PDACs refer to T2-4 N0M0 and nodal or distant metastatic PDAC stages diagnosed during the follow-up phase of HRI surveillance. This study aimed to quantify late-stage PDACs during HRI surveillance and identify associated clinicoradiologic factors. METHODS A systematic search (PROSPERO:CRD42018117189) from Cochrane Library, Embase, Google Scholar, Medline, PubMed, Scopus, and Web of Science was last performed on April 18, 2021. Only original HRI surveillance manuscripts which specified follow-up strategies were included, while studies with only baseline information were excluded. Cumulative incidences of advanced neoplasia: high-grade precursors and all PDACs, and surveillance-detected/interval late-stage PDACs were calculated through random-effects model. Incidence of late-stage PDACs underwent metaregression to identify association with HRI clinicoradiologic features. Publication bias was assessed through the Funnel plot and Egger's Regression line. RESULTS Thirteen original surveillance studies included 2169 HRIs followed over 7302.72 patient-years. Cumulative incidence of advanced neoplasia and late-stage PDACs was 3.3 [95% CI:0.6-7.4] and 1.7 [95% CI:0.2-4.0] per 1000 patient-years, respectively. Late-stage PDACs lacked significant association with surveillance imaging, baseline pancreatic morphology, study location, genetic background, gender, or age. Limited information on diagnostic error, symptoms, timing of presentation, lesion site, and surveillance adherence precluded formal meta-analysis. CONCLUSION A sizable proportion of late-stage PDACs were detected during follow-up. Their incidence lacked association with baseline clinicoradiologic features. Further causal investigation of stage-based outcomes is warranted for overall improvement in HRI surveillance.