The accuracy of cyst fluid carcinoembryonic antigen in differentiating between benign and malignant pancreatic cysts is poor, and the antigen should not be used as a sole marker for guiding surgical decision making, results from a meta-analysis of available literature on the topic suggests.
"The clinical value of cyst fluid CEA should be limited only to distinguishing mucinous from nonmucinous cystic lesions," Dr. Saowanee Ngamruengphong and her colleagues from the division of gastroenterology and hepatology at Mayo Clinic Florida, Jacksonville, wrote in an article in Digestive and Liver Disease (2013 June 18 [doi: 10.1016/j.dld.2013.05.002]). "Large, multicentric, well-designed trials are needed to further characterize the role of cyst fluid tumor marker and molecular analysis in the evaluation of pancreatic cysts."
Results from two previously published articles in the medical literature showed that a cyst fluid EA level of 192-200 ng/mL had 80% accuracy in differentiating between mucinous and nonmucinous cysts (Gastroenterology 2004;126:1330-6 and Pancreatology 2012;12:183-97).
In an effort to determine the diagnostic accuracy of cyst fluid CEA in discriminating benign from malignant pancreatic cystic neoplasms, the authors of the current study conducted a literature search of Medline and Embase databases for studies published before October 2012. They used the following keywords: "pancreas OR pancreatic cystic lesion," "tumor marker OR carcinoembryonic antigen OR CEA," and "diagnosis." A total of eight published articles involving 504 patients were included in the final analysis. Random-effects models were used to calculate pooled estimates of diagnostic precision.
Dr. Ngamruengphong and her colleagues reported that the CEA cutoff level for determining a malignant cyst ranged from 109.9 to 6,000 mg/mL, and that the pooled sensitivity of cyst fluid CEA in the prediction of malignant pancreatic cysts was 63% while the pooled specificity was 63%. In addition, the positive likelihood ratio was 1.89, the negative likelihood ratio was 0.62, and the diagnostic odds ratio was 3.84.
A subgroup analysis of 227 patients with mucinous cysts revealed similar results: a pooled sensitivity of 65%, a pooled specificity of 66%, and a diagnostic odds ratio of 4.74.
"Our findings support the current guidelines, which do not recommend the use of fluid cyst CEA to diagnose malignant pancreatic cysts," the researchers wrote.
They acknowledged certain limitations of the study, including the fact that there was significant heterogeneity among the studies and that the small sample sizes in the included studies "could potentially be subject to selection bias."
The researchers stated that they had no relevant financial conflicts to disclose.