CEA stands for carcinoembryonic antigen. It is a protein found in the tissues of a developing baby. CEA levels normally become very low or disappear after birth. Healthy adults should have very little or no CEA in their body. This test measures the amount of CEA in the blood, and sometimes in other body fluids.
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CONTEXT: The relevance of colorectal adenocarcinoma lies in its high incidence, with the liver being the organ most frequently affected by distant metastases. Nevertheless, despite this, they are occasionally susceptible to curative treatment.
Diagnosis of liver metastases was made through computed tomography, magnetic resonance imaging and computed tomography during arterial portography.
Samples of peripheral blood, portal system blood, and gallbladder bile were collected from patients during the surgical procedure. A control group composed of 18 organ donors underwent the same material collection procedures. CEA level determination was made through fluoroimmunoassay. In the portal system, serum mean values found were 1.
Mean values found in gallbladder bile were 4. Determination of CEA both in peripheral serum and in gallbladder bile enabled patients with liver metastases to be distinguished from those without such lesions.
The level of CEA in gallbladder bile, however, seems to lead to a more accurate diagnosis of liver metastases secondary to colorectal adenocarcinoma. The relevance of colorectal adenocarcinoma lies in its high incidence, with the liver being the organ most frequently affected by distant metastases.
Diagnosis is particularly based on imaging techniques which, despite relevant advances, still present limitations, particularly with regard to very small lesions. The procedures that follow were in accordance with the ethical standards of the committee responsible for human experimentation and with the Helsinki Declaration of , as revised in From December to February , 45 patients hospitalized in the Surgical Gastroenterology Discipline ward with a diagnosis of colorectal adenocarcinoma were enrolled.
Patients with associated diseases, such as cholelithiasis, obstruction of the biliary pathways, intestinal inflammatory diseases, chronic or acute liver diseases and pancreatitis, were not included. For the classification of patients with and without liver metastases, three preoperative parameters were used, based on imaging techniques computer tomography [CT], magnetic resonance [IRM] and computed arterial portography 7 [CTAP] and intraoperative assessment.
Thus, group I, which included 30 patients without liver metastases, and group II, which included 15 patients with liver metastases were created. Eighteen organ-donor patients were used as the control group. None had cholelithiasis, obstruction of the biliary pathways, cirrhosis, liver schistosomiasis or pancreatitis. With regard to gender, the control group was composed of 13 males and 5 females, with ages ranging from 19 to 66 years, mean age In group I, 9 males and 21 females were studied, with ages ranging from 28 to 83 years, mean age As for Dukes classification, 20 Group I was composed of 6 patients presenting Dukes A classification, 8 Dukes B, 12 Dukes C, and 4 were not classified as they underwent no tumor resection.
Imaging was always analyzed by two single examiners from the Imaging Diagnosis Department, who considered the scanning either positive or negative, according to the presence or absence of images suggesting liver metastases. The surgical inventory was made by the surgeon following the collection of both gallbladder bile and portal system blood.
Following the macroscopic assessment of the liver, bimanual palpation was performed. Whenever the surgeon had any doubt, biopsy of the lesion was performed. Peripheral venous blood was collected during anesthetic induction, by direct puncture of an upper limb vein. Ten ml was collected into a dry tube, which was centrifuged to separate serum. At surgery, all patients were submitted to material collection soon after the abdominal cavity was opened, prior to the handling of the tumor or to the surgical inventory.
In the control group, bile collection was performed before the liver was excised. Gallbladder bile was collected by puncture of the gallbladder fundus after a purse string suture using absorbable material. The Kruskal-Wallis test 21 was used, separately, to compare every CEA level found in the peripheral serum, portal system serum and bile among the groups studied.
The Friedman test 22 was used to compare CEA levels in the peripheral serum, portal system serum and bile, between each other, within each group. Whenever a statistically significant difference among the groups was detected, the multiple comparisons test was applied to identify the difference.
In order to determine the optimal normality limit value for CEA levels in bile, i. CEA levels obtained in peripheral serum were as follows: in group I patients, values ranged from 0.
No significant difference was found between values obtained in group I and the control group. CEA levels obtained in bile were as follows: in group I patients, values ranged from zero to No significant differences were found between values obtained in group I and the control group.
The cutoff point for the CEA level in bile was 7. Sensitivity found for this value was Bile CEA levels tested were those close to the ones that presented optimal sensitivity and specificity in relation to the presence of colorectal adenocarcinoma in the 48 patients studied in groups I and control. Two CEA levels in bile determined the largest areas under the curve: For the For the 2.
For the 8. CEA in peripheral serum was found to allow no distinction between patients in the control group from those without liver metastases, i.
CEA in peripheral blood is not a good diagnosis test. This agrees with other studies in the literature that show CEA in peripheral serum to be of little sensitivity and specificity in cases of early colorectal adenocarcinoma. It was also found that CEA in peripheral serum allowed patients with liver metastases to be distinguished from those without liver metastases. This finding also agrees with data found in the literature showing improved sensitivity in the presence of liver metastases.
The distinction in this latter case had more efficacy, due to increased sensitivity and specificity. Statistical corroboration lies in the significant difference found between the ROC curves areas for both levels.
According to some authors, 17, 19, 21 tumor cell products, with CEA among them, would be more concentrated in smaller amounts of bile than in larger amounts of serum and, furthermore, bile would be more exposed to such tumor products. These are plausible explanations, but there is controversy regarding the origin of CEA in bile, as CEA in bile may arise, at least in part, from the primary tumor.
A suggestion for studies that may solve such controversies, and which has already been presented by other authors, 23 is to determine the level of CEA in bile prior to and following resection of the primary tumor.
A further issue which calls for discussion is that of false-positive results regarding CEA levels in bile, i. One of the possibilities is again the origin of CEA in the primary tumor, and a further possibility is cross-reactions. The existing methods are known to be adequate for determining CEA in serum, and failures may occur when they are used to determine CEA in bile. And why would it be important to know whether CEA in bile is predictive of the appearance of liver metastases?
Because according to some authors, , , 18 such a group of patients may benefit from some kind of prophylactic treatment to avoid the development of liver metastases. The main conclusion of this study is that CEA in bile increases in the presence of liver metastases secondary to colorectal adenocarcinoma. Second, it may be concluded that CEA in bile is better than CEA in peripheral serum for the diagnosis of liver metastases.
Two further questions remain to be answered in subsequent studies. One deals with the origin of CEA in bile and the other one concerns the false-positive results. Cancer statistics CA Cancer J Clin ; The survival of patients with colorectal cancer treated in a regional hospital. Br J Surg ; Occult hepatic metastases in colorectal carcinoma. Ferrucci JT. Liver tumor imaging: current concepts. Rev Bras Colo-proctol ;15 Suppl. Gold P, Freedman SO. Demonstration of tumor-specific antigens in human colonic carcinoma by immunological tolerance and absorption techniques.
J Exp Med ; Fletcher RH. Carcinoembryonic antigen. Ann Intern Med ; Bell H. Alpha-fetoprotein and carcinoembryonic antigen in patients with primary liver carcinoma, metastatic liver disease, and alcoholic liver disease. Scand J Gastroenterol ; Relationship between colorectal liver metastases and CEA levels in gallbladder bile.
Ann Surg ; Rev Bras Colo-proctol ; Measurement of bile CEA levels in patients with colorectal cancer: is it of value for diagnosis of occult liver metastases aiming at prophylactic regional hepatic chemotherapy? Gan To Kagaku Ryoho ; Elevated biliary levels in colorectal patients: a prognostic factor?
Eur J Cancer ;29A:S Carcinoembryonic antigen CEA in serum and bile of colorectal cancer patients with or without detectable liver metastases. Anticancer Res ; Potential value of biliary CEA assay in early detection of colorectal adenocarcinoma liver metastases. Eur J Surg Oncol ; Detection of occult liver metastases by measurement of biliary carcinoembryonic antigen concentrations.
Eur J Surg ; Relationship between colorectal liver metastases and CEA levels in gallbladder bile: preliminary results. World Congress of the International College of Surgeons Bologna: Monduzzi; pp Proceedings. Detection of occult liver metastases in colorectal cancer by measurement of biliary carcinoembryonic antigen.
Carcinoembryonic antigen CEA describes a set of highly related glycoproteins involved in cell adhesion. CEA is normally produced in gastrointestinal tissue during fetal development, but the production stops before birth. Serum levels can also be elevated in heavy smokers. CEA are glycosyl phosphatidyl inositol GPI cell-surface-anchored glycoproteins whose specialized sialo fucosylated glycoforms serve as functional colon carcinoma L-selectin and E-selectin ligands, which may be critical to the metastatic dissemination of colon carcinoma cells. Freedman in human colon cancer tissue extracts. The CEA blood test is not reliable for diagnosing cancer or as a screening test for early detection of cancer. Serum from individuals with colorectal carcinoma often has higher levels of CEA than healthy individuals above approximately 2.
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Carcinoembryonic antigen levels are not useful in screening the general population for undetected cancers. Carcinoembryonic antigen CEA is a glycoprotein normally found in embryonic entodermal epithelium. Increased levels may be found in patients with primary colorectal cancer or other malignancies including medullary thyroid carcinoma and breast, gastrointestinal tract, liver, lung, ovarian, pancreatic, and prostatic cancers. Serial monitoring of CEA should begin prior to therapy to verify post therapy decrease in concentration and to establish a baseline for evaluating possible recurrence. Levels generally return to normal within 1 to 4 months after removal of cancerous tissue.
Gold P, Freedman SO. Specific carcinoembryonic antigens of the human digestive system. J Exp Med ; Histochem Cell Biol ; Freedman SO. Antigens in tumours. Scientific Foundations of Oncology.