The Oncologist, Vol. 10, No. 7, 501-507, August 2005; doi:10.1634/theoncologist.10-7-501 © 2005 AlphaMed Press
Diagnostic Value of CYFRA 21-1, CEA, CA 19-9, CA 15-3, and CA 125 Assays in Pleural Effusions: Analysis of 116 Cases and Review of the Literaturea Pulmonary Institute and b Department of Internal Medicine, Rabin Medical Center, Beilinson Campus, Petah Tiqva, affiliated with Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; c Department of Internal Medicine, Shaare-Zedek Medical Center, Jerusalem, Israel Correspondence: Mordechai Kramer, M.D., Pulmonary Institute, Rabin Medical Center, Beilinson Campus, Petah Tiqva, Tel Aviv, 49100, Israel. Telephone: 972-3-9377221; Fax: 972-3-9377142; e-mail: kramerm{at}netvision.net.il
Levels of tumor markers in pleural effusions may help to establish the diagnosis of pleural malignancy, but the precise diagnostic value of each marker remains unclear. The aim of this study was to assess the diagnostic value of five common pleural fluid tumor markers, carcinoembryonic antigen (CEA), cytokeratin fragment (CYFRA) 21-1, cancer antigen (CA) 15-3, CA 19-9, and CA 125, and to review the literature from the past 15 years. Pleural fluid samples were collected prospectively from 116 patients and assayed for CEA, CYFRA 21-1, CA 15-3, CA 19-9, and CA 125 levels. A MEDLINE search of the English-language literature from the past 15 years was also done. Effusions were classified as benign or malignant on the basis of their definitive pathologic or cytologic diagnoses. The levels of all pleural tumor markers were statistically significantly higher in the malignant group than in the benign group. The marker with the highest accuracy was CEA (85.3%); CA 15-3, CYFRA 21-1, and CA 19-9 had similar accuracies (75.2%, 72.4%, and 71.5%, respectively), and CA 125 had the lowest accuracy (40.5%). On univariate analysis, tumor-marker combinations did not result in a greater accuracy than that of CEA alone. On multivariate logistic regression, CA 15-3 and CYFRA 21-1 were significant predictors of malignancy. Among the nine reports in the literature comparing 11 different tumor markers, CEA, CA 15-3, and CYFRA 21-1 yielded the best results. We conclude that pleural fluid analysis should include CEA for the diagnosis of malignancy. CA 15-3 and CYFRA 21-1 may serve as alternative options. Key Words. Pleural effusion • Tumor marker • Sensitivity • Specificity • Accuracy
Pleural effusions are common complications of a wide variety of diseases. It is important to elucidate their precise etiologies to differentiate benign from malignant effusions [1]. The initial diagnostic approach includes thoracocentesis and cytologic, histologic, and biochemical examinations [2]. However, the sensitivity of these noninvasive techniques is only 40%70% [3, 4]. To improve upon these rates, a number of tumor markers in the pleural fluid have been intensively evaluated. The most common markers found to be of diagnostic significance were carcinoembryonic antigen (CEA), cancer antigen (CA) 15-3, CA 19-9, cytokeratin fragment (CYFRA 21-1), and CA 125 [2, 57]. However, their precise sensitivities in identifying malignant pleural effusions remain controversial. Moreover, few data exist on tumor-marker levels for different etiologies. The aim of this study was to determine the diagnostic capabilities of these five tumor markers in pleural fluid. To reach practical conclusions, we reviewed the literature from the past 15 years.
A total of 116 pleural fluid samples was prospectively collected from 116 patients at the Pulmonary Institute of Rabin Medical Center between March 2003 and December 2003. The study group included 65 men (56%) and 51 women (44%). The effusions were classified as benign or malignant on the basis of their definitive pathologic diagnoses. The effusions were considered malignant if malignant cells were found on cytologic examination or in a biopsy specimen. In cases where cytologic examinations were negative (n = 18), we did closed pleural biopsies. Five patients underwent video-assisted thoracoscopic surgery (VATS). The effusions were considered parapneumonic if they were associated with acute febrile illness with purulent sputum, pulmonary infiltrate, and responsiveness to antibiotic treatment or if a micro-organism was identified in the pleural fluid in the absence of any other cause of the pleural effusion. Tuberculous pleurisy was diagnosed by positive cultures for Mycobacterium tuberculosis or when the pleural biopsy specimen showed typical epithelioid cell granuloma. A diagnosis of congestive heart failure (CHF) was made by findings of an enlarged heart, pulmonary venous congestion on the radiograph, and peripheral edema, with response to CHF treatment and absence of malignancy or pulmonary infiltrates associated with an inflammatory process. The diagnosis of postcardiotomy syndrome (Dresslers syndrome) was made when the pleural effusion developed after injury to the heart and CHF, pulmonary embolism, and pneumonia were ruled out, and a response to treatment with anti-inflammatory agents or corticosteroids was noted. Pleural fluid was collected from each patient prior to any therapy. The supernatant was obtained by centrifugation at 300 rpm for 15 minutes and stored at 20°C until assayed. The clinicians who identified the tumor markers were blinded to the definitive diagnosis of the pleural effusions. CEA and CA 19-9 levels were determined by the solid-phase, two-site chemiluminescent enzyme immunometric assay, and CA 15-3 levels were determined by the sequential, two-site chemiluminescent enzyme immunometric assay (Immulite®; Diagnostic Products Corporation, Los Angeles, http://www.dpcweb.com). CYFRA 21-1 levels were measured with commercially available enzyme-linked immunosorbent assay kits (CYFRA 21-1 Enzymun-Test®; Roche Diagnostics Corporation, India-napolis, http://www.roche-applied-science.com). This test is based on the sandwich enzyme immunoassay with streptavidin technology. CA 125 analysis was performed with the BYK-Sangtec System radioimmunoassay-mat 280 (double-antibody immunoradiometric assay, Dia-Sorin Diagnostic Group, Dietzenbach, Germany, http://www.diasorin.com). The cutoff levels of CEA, CYFRA 21-1, CA 15-3, CA 19-9 and CA 125 were 05 ng/ml, 03.3 ng/ml, 030 U/ml, 037 U/ml, and 035 U/ml, respectively. A MEDLINE search of the English-language literature from the last 15 years was performed using the key words "tumor marker," "pleural effusion," "CEA," "CA 125," "CA 19-9," "CA 15-3," "CYFRA 21-1," and "malignant," alone and in combination. Only reports that compared at least two tumor markers were included.
Statistical Analysis Differences in means of continuous variables between two groups of patients (malignancy and nonmalignancy) were analyzed by the t-test. To predict malignancy, a stepwise logistic regression model was fitted to the data. Odds ratios and 95% confidence intervals (CIs) were calculated from the model. A p value of .05 or less was considered statistically significant.
Seventy-two effusions were defined as benign and 44 were defined as malignant. Of the 72 patients with benign effusions, 46 (64%) were men and 26 were women, with a mean age of 69.6 ± 13.6 years (range 3491). Of the 44 patients with malignant effusions, 20 were men and 24 were women, with a mean age of 70.3 ± 11.9 years (range 4288). The causes of the benign and malignant pleural effusions are given in Table 1
Of the 44 patients with malignancies, 21 had lung cancer. Only two of these had small-cell lung cancer and all the others had non-small cell lung cancer. None of the patients was stage I. Four patients were stage II, seven patients were stage III, and 10 patients were stage IV.
The traditional pleural markers, including the cell count, blood and pleural fluid levels of total protein and lactate dehydrogenase (LDH), and the cytologic yields, are presented in Table 2
The means and standard deviations of the pleural fluid levels of CEA, CA 125, CA 19-9, CA 15-3, and CYFRA 21-1 in patients with benign and malignant effusions are presented in Table 3
On univariate analysis, combining the findings for CEA, CA 15-3, and CYFRA 21-1 (Table 6) resulted in a greater sensitivity than that of CEA alone. However, it produced a lower specificity, and therefore accuracy, than with CEA alone.
Table 5
When a multivariate logistic regression model was fitted to the data, the factors found to be statistically significantly predictive of pleural malignancy were CA 15-3 and CYFRA 21-1 (p = .0037 and p = .0031, respectively), with odds ratios of 1.058 (95% CI, 1.0191.099) and 1.006 (95% CI, 1.0021.010).
Review of the Literature
Six tumor markers, namely CA 72-4, CA 549, total sialic acid (TSA), squamous cell carcinoma (SCC) antigen, neuron-specific enolase (NSE), and mucinous carcinoma-associated antigen (MCA), were studied in only one or three studies [7, 911, 1416]. Owing to the limited available data, we could not determine the diagnostic values of those markers. CA 125 was also assayed in only three reports, including ours [10, 11], which yielded conflicting results. CEA was assayed in eight of nine earlier studies. In three of those, it yielded the highest diagnostic value [12, 15, 16], as in the present study. In two studies, it was second to CA 15-3 [7, 14], and in one study, it was second to CYFRA 21-1 [13]. Only one report found both CYFRA 21-1 and CA 15-3 to be of higher diagnostic value than CEA [9]. CA 15-3 was assayed in five of nine studies in the literature [7, 9, 12, 14, 16]. In two of those studies, it yielded the highest diagnostic value [7, 14]. In one study, it was second to CEA, in agreement with the present study, and in one study it was second to CYFRA 21-1 [9]. CYFRA 21-1 was assayed in five reports in the literature [9, 10, 12, 13, 15]. Two found it to be the best tumor marker of malignant pleural effusion [9, 13] and, in three studies, it was second to other markers. Our findings agree with the latter reports. CA 19-9 was assayed in four studies [7, 9, 11, 16]. None of them found it to be one of the best tumor markers. This was true of the present study as well. In three reports, CA 19-9 had the worst results [7, 9, 16].
The determination of tumor markers in pleural effusions has been proposed as an alternative, noninvasive way of establishing a diagnosis of pleural malignancy. However, the use of these measurements in clinical practice remains controversial. The results of the present study demonstrate that the determination of CEA alone in pleural effusions yields the best results. Our review of the literature led to a similar conclusion. The CYFRA 21-1 assay, which detects a soluble fragment of cytokeratin 19 that is expressed by all histologic types of lung cancer [17], has been proven capable of detecting epithelial carcinomas, especially SCC [18]. Its sensitivity most likely depends on the prevalence of squamous cell malignancies in the studied population. Studies on the diagnostic significance of the CYFRA 21-1 level in pleural effusions in differentiating malignant from benign lung disease [19, 20] found it to be a reliable marker. The present study supports those findings.
Elevated levels of pleural CEA have also been demonstrated in malignant lung disease [21, 22]. In our series, CEA had the best diagnostic accuracy (85.3%) of all the markers tested, in agreement with earlier studies (Table 6
Five patients with negative cytologies of their pleural effusions had positive CEA levels. All of them were eventually shown to have a malignancy. In addition, 21 patients had cytologies that were equivocal or suspicious for malignancy. Thirteen of them had CEA elevation and all of them proved to have malignancies. Based on the available data, we recommend the use of CEA as a marker in cases of suspected malignant pleural effusion (Fig. 1
CA 15-3, which apparently has a high specificity for breast cancer, has not been as extensively evaluated in the differential diagnosis of malignant pleural effusions as CEA. The few relevant studies, however, in addition to ours, indicate that it may be one of the more specific tumor markers [10, 12]. Earlier studies reported that the pleural fluid CA 19-9 level had a low sensitivity but a high specificity in the diagnosis of malignant effusions [23]. We also found CA 19-9 to have a low sensitivity and a high specificity, and a similar accuracy to CYFRA 21-1 and CA 15-3. According to immunohistochemical studies, CA 125 is released from the pleura and peritoneum [24, 25]. Only two reports compared CA 125 with other markers, and both found it to have a high sensitivity for discriminating malignant from benign pleural effusions, but a low specificity [23, 26]. The authors of those studies concluded that CA 125 alone was insufficient for diagnosis and was of value only with concurrent measurements of other tumor markers. Similarly, in our study, CA 125 had a high sensitivity and a low specificity. Therefore, we do not recommend its use in the tumor-marker profile of patients with suspected malignant pleural effusions. Data on CA 72-4, CA 549, NSE, TSA, and SCC antigen remain sparse [7, 9, 11, 14], and further studies are needed to establish their diagnostic value in malignant pleural effusion.
On analysis of the diagnostic role of various tumor-marker combinations (Table 6
Based on our findings and the review of the literature, we suggest using the algorithm outlined in Figure 1 In conclusion, our data suggest that measurement of CEA levels in pleural effusions yields the highest diagnostic accuracy. Other tumor markers, especially CA 15-3 and CYFRA 21-1, could serve as alternatives when CEA assay is not available. CA 125 and CA 19-9 are not contributory. CEA assay should be included in the evaluation of every patient with suspected malignant pleural effusion. Based on our data, we think that every patient with unexplained pleural effusion should undergo thoracocentesis with tumor-marker evaluations. Patients with negative cytologic examinations and positive tumor-marker levels should undergo further invasive procedures, and the final step should rest upon demonstration of positive cytology or biopsy of the pleura, which would result in management decisions.
The authors indicate no potential conflicts of interest.
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