Elsevier

Clinical Biochemistry

Volume 46, Issue 9, June 2013, Pages 814-818
Clinical Biochemistry

CEA, AFP and CA 19-9 analysis in peritoneal fluid to differentiate causes of ascites formation

https://doi.org/10.1016/j.clinbiochem.2013.02.010Get rights and content

Abstract

Objectives

Tumor marker analysis in ascites has been proposed as a measure to aid in the diagnosis of malignancy. The objectives of this study were to establish tumor marker cut-offs and determine the diagnostic performance of measuring CEA, CA 19-9 and AFP in ascites for differentiating between non-malignant and malignant etiologies.

Design and methods

Ascites from 137 patients (83 non-malignant, 54 malignant) was assayed for CEA, CA 19-9 and AFP concentrations by immunoassay. Diagnostic cut-offs were established via ROC curve analysis. Performance was compared to cytology findings and patient history following medical chart review. Analysis based on cytological findings in combination with tumor marker testing, as well as subset analysis by tumor marker secretion was also performed.

Results

Concentrations of CEA, CA 19-9 and AFP were significantly higher in patients with malignant ascites versus non-malignant etiologies. The diagnostic cut-off, sensitivity and specificity for CEA were 3.5 ng/mL, 31% and 95%, respectively; for CA 19-9 were 72 U/mL, 30% and 95%; and for AFP were 5 ng/mL, 17% and 95%. Using cytological findings in conjunction with tumor marker results improved the sensitivity of CEA, CA 19-9 and AFP to 57.4%, 64.8%, and 59.3%, respectively. Improvement in sensitivity was seen when subset analysis by causative malignancy was performed.

Conclusions

Tumor marker analysis in ascites, especially in subset analysis by type of malignancy, demonstrated utility for differentiating non-malignant from malignant etiologies. This analysis should not replace cytology, but offers potential for differentiation in situations where cytology is inconclusive, or in patients with suspected malignancies known to secrete these markers.

Highlights

► CEA, CA 19-9 and AFP were measured in ascites to identify malignancy. ► Cut-offs were established, and diagnostic performance was evaluated. ► Subset analysis based on malignancy type was performed for each tumor marker. ► We report the utility of CEA, CA 19-9 and AFP to be used complementary to cytology.

Introduction

Ascites is a pathological condition described by fluid accumulation in the peritoneal cavity. Although cirrhosis and portal hypertension are the main causes of ascites (~ 85% of cases), malignant conditions, such as peritoneal carcinomatosis, and other metastatic carcinomas within the peritoneal cavity may be the reason [1]. Accumulation of fluid in these conditions can be due to blockage of the lymphatic system, secondary portal hypertension, and increased vascular permeability as a consequence of tumor obstructions.

The current strategy for identifying malignancy-associated ascites focuses on the use of cytological analysis of peritoneal fluid. This relies on the presence of malignant cells that have been sloughed off into the abdominal fluid, which must then be detected on a smear. While this is a practical approach for some cases, specifically for peritoneal carcinomatosis which accounts for 53% of malignancy-associated ascites, other malignancies, such as hepatocellular carcinoma, metastatic carcinoma to the liver, or chylous ascites due to malignancy may be problematic since these are less likely to have cell shedding [2]. The specificity for cytological analysis is very high, but the lack of cell exfoliation in all malignancies lowers the sensitivity of cytology to 40–60% [3]. In these situations, it is advantageous to utilize other testing strategies for characterizing the cause of peritoneal fluid accumulation.

Measurement of tumor markers in peritoneal fluid is often used to aid in differentiation of non-malignant from malignancy-associated ascites, especially in cases where cytology is uninformative. The utility of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9), and alpha-fetoprotein (AFP) in differentiating malignancy from non-malignant ascites has been controversial due to conflicting findings, and in some cases, low sensitivity and specificity of these markers [4], [5]. This may be due, in part, to the heterogeneity in the types of malignancies used in the evaluation. An improvement on these studies lies in subtype analysis by correlating tumor marker values with malignancies known to have elevations of these antigens in serum. This has shown to improve sensitivity in tumor marker analysis in pleural fluid [6].

The aim of this study was to correlate cytological findings with tumor marker analysis as a way to improve the differentiation of malignancy-associated ascites from non-malignant ascites. Cut-off values that provide high specificity were established and each tumor marker was assessed for diagnostic performance in malignancies known to secrete the tumor marker in serum.

Section snippets

Patients

The Mayo Clinic Institutional Review Board approved this study. Peritoneal fluid samples were collected from 137 patients (66 males and 71 females) seen at Mayo Clinic, Rochester, MN between May 2011 and December 2011 and underwent a paracentesis for cytology evaluation. A designation of non-malignant (n = 83) or malignant (n = 54) was made for each sample based on cytology findings, biopsy results and long-term follow-up care. Clinical findings were reviewed in the medical record for each patient

Results

Since CEA, CA 19-9 and AFP immunoassays are not currently FDA cleared for use in peritoneal or other body fluids, validation studies were performed. Accuracy, intra- and inter-assay precision, limit of detection, limit of quantitation, reportable range and interference studies were assessed, the results of which can be found in Table 2.

A total of 137 ascites samples were utilized in this study. The concentrations of CEA, CA 19-9 and AFP in malignant ascites were significantly higher than in

Discussion

Analysis of CEA, CA 19-9 and AFP was performed to determine their usefulness in distinguishing non-malignant from malignant etiologies of ascites. Analysis was performed using tumor marker cut-offs that achieved high specificity to reduce false positives that might lead to additional unnecessary testing; as a consequence, the sensitivities were lower than previous reports [5], [14], [15]. Using this approach, measurement of tumor markers did not show improved sensitivity over cytology when all

Conclusions

Overall, this study enhances the understanding of the utility of CEA, CA 19-9 and AFP in the classification of non-malignant and malignant ascites. When applied to all malignant causes of ascites, the sensitivity of the tumor markers was limited. However, when the analysis was tailored to those malignancies that are known to secrete these tumor markers in the serum, the performance of the tests improved. Therefore, narrowing tumor marker testing based on the patient's diagnosis differential and

References (19)

  • J.S. Hackbarth et al.

    Performance of CEA and CA 19-9 in identifying pleural effusions caused by specific malignancies

    Clin Biochem

    (2010)
  • K.S. Goonetilleke et al.

    Systematic review of carbohydrate antigen (ca 19-9) as a biochemical marker in the diagnosis of pancreatic cancer

    Eur J Surg Oncol

    (2007)
  • B.A. Runyon et al.

    The serum–ascites albumin gradient is superior to the exudate–transudate concept in the differential diagnosis of ascites

    Ann Intern Med

    (1992)
  • B.A. Runyon et al.

    Ascitic fluid analysis in malignancy-related ascites

    Hepatology

    (1988)
  • H. Motherby et al.

    Diagnostic accuracy of effusion cytology

    Diagn Cytopathol

    (1999)
  • R. Sari et al.

    The importance of serum and ascites fluid alpha-fetoprotein, carcinoembryonic antigen, ca 19-9, and ca 15–3 levels in differential diagnosis of ascites etiology

    Hepatogastroenterology

    (2001)
  • Y. Tuzun et al.

    How to increase the diagnostic value of malignancy-related ascites: discriminative ability of the ascitic tumour markers

    J Int Med Res

    (2009)
  • A.H. Chevinsky

    CEA in tumors of other than colorectal origin

    Semin Surg Oncol

    (1991)
  • A.M. Ballesta et al.

    Carcinoembryonic antigen in staging and follow-up of patients with solid tumors

    Tumour Biol

    (1995)
There are more references available in the full text version of this article.

Cited by (29)

  • Hybrid panel of biomarkers can be useful in the diagnosis of pleural and peritoneal effusions

    2019, Clinica Chimica Acta
    Citation Excerpt :

    However, laboratory tests do not always clarify the etiology of an effusion, stimulating the search for new biomarkers to be used with this purpose. Cirrhosis and portal hypertension are the main causes of ascites (approximately 85% of cases), although infection and malignancy can occur with accumulation of peritoneal fluid [1,2]. Pleural effusion, in turn, may result from pressure imbalance in pleural space due to systemic diseases - such as cardiac transudate or, in the case of exudates, to reflect complications of infections, neoplasm, trauma, drug use, autoimmune diseases or idiopathic conditions [3].

  • Chemiluminescent dual-enzyme immunoassays capable of simultaneously quantifying carbohydrate antigen 19–9 and carcinoma embryonic antigen in a sample

    2019, Analytica Chimica Acta
    Citation Excerpt :

    For example, various biomarkers capable of early diagnosing human cancers have been reported and quantified in human fluidic sample (e.g., plasma, serum, urine, whole blood) using the in-vitro immunoassays [1–3]. Generally, in order to early diagnose and rapidly prognose a specific cancer, analytical data for a couple of specific biomarkers in a sample are required [4–7]. This is because the diagnosis of human cancer with the analyses of at least two biomarkers in a sample is more accurate and more reproducible than that with the quantification of a single biomarker only [8–10].

  • Alpha-fetoprotein in pericardial, peritoneal, and pleural fluids: A body fluid matrix evaluation

    2018, Clinical Biochemistry
    Citation Excerpt :

    Along with its use in maternal screening for fetal neural tube defects, serum AFP is also used clinically as a tumor marker for malignancies including liver cancer (e.g. pediatric hepatoblastoma and adult hepatocellular carcinoma), as well as nonseminomatous germ cell tumors [2,3]. The determination of AFP concentrations in various body fluid effusions is occasionally requested by practitioners, as it may provide supportive evidence (along with cytology and radiographic imaging) when trying to differentiate between nonmalignant and malignant causes of effusions [4–6]. Such estoteric requests are often directed to reference laboratories, which prompted the initiation of the present validation experiments.

View all citing articles on Scopus
View full text