Delgado, Adriana M

ABSTRACT Background and Objectives Occult intra‐abdominal metastases are identified in approximately 20% of patients with radiographically localized pancreatic ductal adenocarcinoma (PDAC) through staging laparoscopy, as peritoneal cytology is limited in sensitivity. Methylated DNA markers (MDMs) have demonstrated high diagnostic accuracy for PDAC in tumor tissue, blood, and pancreatic secretions. This study assesses the feasibility and diagnostic performance of MDMs in peritoneal lavage fluid collected during staging laparoscopy, comparing their performance to mutant KRAS (m KRAS ) detection. Methods DNA from peritoneal lavage fluid of PDAC patients was analyzed for m KRAS mutations (codons 12, 13, and 61) using droplet‐digital PCR and for 13 MDMs and a reference gene (B3GALT6) using quantitative methylation‐specific PCR. An MDM score was generated from the average signal of the 13 MDMs and evaluated for its ability to detect intra‐abdominal metastases via receiver operator characteristic (ROC) analysis. Results Among 48 patients, 15 (31%) had intra‐abdominal metastases. The MDM score showed 87% sensitivity and 90% specificity (AUC = 0.98), outperforming m KRAS , which showed 40% sensitivity and 85% specificity (AUC = 0.62; p < 0.0001). Conclusions MDMs in peritoneal lavage fluid may enable highly accurate molecular staging of PDAC and warrant validation in larger studies.

ImportanceIntraductal papillary mucinous neoplasms (IPMNs) are pancreatic cysts that can give rise to pancreatic cancer (PC). Limited population data exist on their prevalence, natural history, or risk of malignant transformation (IPMN-PC).ObjectiveTo fill knowledge gaps in epidemiology of IPMNs and associated PC risk by estimating population prevalence of IPMNs, associated PC risk, and proportion of IPMN-PC.Design, Setting, and Participants: This retrospective cohort study was conducted in Olmsted County, Minnesota. Using the Rochester Epidemiology Project (REP), patients aged 50 years and older with abdominal computed tomography (CT) scans between 2000 and 2015 were randomly selected (CT cohort). All patients from the REP with PC between 2000 and 2019 were also selected (PC cohort). Data were analyzed from November 2021 through August 2023.Main outcomes and MeasuresCIs for PC incidence estimates were calculated using exact methods with the Poisson distribution. Cox models were used to estimate age, sex, and stage–adjusted hazard ratios for time-to-event end points.ResultsThe CT cohort included 2114 patients (1140 females [53.9%]; mean [SD] age, 68.6 [12.1] years). IPMNs were identified in 231 patients (10.9%; 95% CI, 9.7%-12.3%), most of which were branch duct (210 branch-duct [90.9%], 16 main-duct [6.9%], and 5 mixed [2.2%] IPMNs). There were 5 Fukuoka high-risk (F-HR) IPMNs (2.2%), 39 worrisome (F-W) IPMNs (16.9%), and 187 negative (F-N) IPMNs (81.0%). After a median (IQR) follow-up of 12.0 (8.1-15.3) years, 4 patients developed PC (2 patients in F-HR and 2 patients in F-N groups). The PC incidence rate per 100 person years for F-HR IPMNs was 34.06 incidents (95% CI, 4.12-123.02 incidents) and not significantly different for patients with F-N IPMNs compared with patients without IPMNs (0.16 patients; 95% CI, 0.02-0.57 patients vs 0.11 patients; 95% CI, 0.06-0.17 patients; P = .62). The PC cohort included 320 patients (155 females [48.4%]; mean [SD] age, 72.0 [12.3] years), and 9.8% (95% CI, 7.0%-13.7%) had IPMN-PC. Compared with 284 patients with non-IPMN PC, 31 patients with IPMN-PC were older (mean [SD] age, 76.9 [9.2] vs 71.3 [12.5] years; P = .02) and more likely to undergo surgical resection (14 patients [45.2%] vs 60 patients [21.1%]; P = .003) and more-frequently had nonmetastatic PC at diagnosis (20 patients [64.5%] vs 130 patients [46.8%]; P = .047). Patients with IPMN-PC had better survival (adjusted hazard ratio, 0.62; 95% CI, 0.40-0.94; P = .03) than patients with non-IPMN PC.Conclusions and RelevanceIn this study, CTs identified IPMNs in approximately 10% of patients aged 50 years or older. PC risk in patients with F-N IPMNs was low and not different compared with patients without IPMNs; approximately 10% of patients with PC had IPMN-PC, and they had better survival compared with patients with non-IPMN PC.