Cyst fluid carcinoembryonic antigen level is not predictive of invasive cancer in patients with intraductal papillary mucinous neoplasm of the pancreas.

Context: Cyst fluid CEA concentration>192 ng/mL has proven accurate to differentiate mucinous from non-mucinous pancreatic cystic neoplasms. It is unclear whether the degree of cyst fluid CEA elevation is predictive of malignant behavior in IPMNs.

Objectives: To determine whether elevated cyst fluid CEA concentrations were predictive of invasive cancer.

Design: Cross sectional study.

Setting: Single National Cancer Institute comprehensive cancer care center experience.

Patients: 47 patients underwent preoperative EUS-FNA with cyst fluid analysis and surgical resection of an IPMN over a 9 year period.

Main Outcome Measurements: Cyst fluid CEA concentrations among the four grades associated with IPMN (low grade dysplasia, moderate dysplasia, high grade dysplasia, and invasive cancer).

Results: The mean±standard deviation cyst fluid CEA concentration increased as the pathology progressed from low grade dysplasia (1,261±1,679 ng/mL) to moderate dysplasia (7,171±22,210 ng/mL) to high grade dysplasia (10,807±36,203 ng/mL). However, the mean CEA level decreased (462±631 ng/mL) once invasive cancer developed (P=0.869). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of a cyst fluid CEA concentration greater than 200 ng/mL for the diagnosis of malignant IPMN (cases of high grade dysplasia and invasive IPMN) was 52.4%, 42.3%, 42.3%, 52.4% and 46.8%, respectively.

Limitations: Single center experience, small patient numbers, retrospective data collection.

Conclusion: The degree of cyst fluid CEA elevation is a poor predictor of malignant degeneration within IPMNs. Clinical management decisions regarding surgical resection should not be based upon degree of cyst fluid CEA elevation.