Risk stratification for malignant potential of intraductal papillary mucinous neoplasms using the apolipprotein-A2 isoforms blood test.

Introduction: High-risk stigmata (HRS) and worrisome features (WFs) are imaging findings that reflect malignant potential of intraductal papillary mucinous neoplasms (IPMNs). The aim of this study was to determine the potential utility of stratifying malignant potential of IPMNs using apolipoprotein-A2 isoforms (apoA2-i) as a blood biomarker.

Methods: A total of 212 patients with IPMNs diagnosed by either magnetic resonance cholangiopancreatography (MRCP) or contrast-enhanced CT, and endoscopic ultrasound (EUS) were retrospectively enrolled. ApoA2-i and CA19-9 of all patients and 295 healthy individuals were measured. The distributions of apoA2-i and CA19-9 were analyzed in association with the malignant potential evaluated by imaging.

Results: In 212 patients with IPMN, 17 had High-risk stigmata (HRS group), 70 had worrisome features (WF group), and 125 had no EUS findings of High-risk stigmata or worrisome features (non-WF group). The median of the apoA2-i Index in the HRS, WF, non-WF, and healthy groups were 57.7, 72.4, 87.5, and 87.9 μg/mL, respectively, with significantly lower levels in the HRS and WF groups (p < 0.001). In contrast, CA19-9 showed no significant difference among the four groups. The area under the curve of the apoA2-i Index to differentiate patients in the HRS and WF groups from the non-WF group was significantly higher than that of the CA19-9 (0.676 vs 0.554, p = 0.029).

Discussion: The diagnostic performance of apoA2-i for detecting IPMN with malignant potential was superior to that of CA19-9. The apoA2-i Index could serve as a useful biomarker for risk stratification and surveillance of IPMNs. (247 words).