TTP6.08 CA19-9 as an Underutilised Surveillance Tool for IPMN Patients

Aims Intraductal papillary mucinous neoplasms (IPMNs) are pre-cancerous pancreatic cystic lesions responsible for up to 20% of pancreatic ductal adenocarcinoma (PDAC) cases due to their malignant potential. Surveillance typically involves imaging with CT or endoscopic ultrasound, both of which are invasive and costly. Current guidelines differ widely, providing limited guidance on the use of CA19-9, a tumour marker that may help assess malignancy risk. This study evaluates the utility of CA19-9 in identifying PDAC risk among IPMN patients, given their risk for both malignant transformation and de novo PDAC. Methods A cohort of 746 IPMN patients was analysed for preoperative CA19-9 levels, resection status, and pathology findings. Patients were grouped into resection (n=27) and non-resection (NR, n=719) cohorts. CA19-9 levels were compared with outcomes. Results Among resected patients, 29.63% had preoperative CA19-9 measurements, while 6.40% of NR patients had at least one CA19-9 measurement. In the NR group, elevated CA19-9 (>37 U/mL) was associated with a higher risk of PDAC (p = 0.0004). Of a total of six cancers in the NR cohort, five were de-novo PDAC and one was malignant transformation of IPMN. Of these, one case involved serial CA19-9 monitoring prior to PDAC confirmation on CT, three had a CA19-9 measurement following PDAC confirmation on CT, and two did not have any form of CA19-9 measured. Conclusion CA19-9 is underutilised in IPMN surveillance despite its potential for identifying high-risk patients. This study underscores the need to refine guidelines to incorporate CA19-9 monitoring for early detection and intervention.