G.G. Bon

Serum tumor marker immunoassays in gynecologic oncology: Establishment of reference values

OBJECTIVE Our purpose was to establish reference values for six monoclonal antibody-based serum immunoassays applied in patients with carcinoma of the female genital tract. STUDY DESIGN Sera from 938 healthy women (median age 48.0 years, range 37 to 76 years) were assayed for levels of CA 125, CA 15.3 (two methods), CA M29, CA M26, and mucin-like cancer antigen (MCA). RESULTS Reference values, defined as those including 95% of healthy controls, were in women with unknown menopausal status as follows: CA 125, 37 U/ml; CA 15.3 (Centocor), 33 U/ml; CA 15.3 (Boehringer Mannheim), 28 U/ml; CA M26, 83 U/ml; CA M29, 13 U/ml; and MCA, 19 U/ml. Postmenopausal values were significantly lower for CA 125 and CA M26 and significantly higher for CA M29 and CA 15.3 (both methods). MCA serum levels were age independent. CONCLUSION Reference values found were not in accord with those generally applied in gynecologic oncology. In addition, serum levels were influenced significantly by menopausal status (except with MCA).

CA 125 in gynecological pathology — a review

The original CA 125 serum tumor marker test is a homologous double-determinant (OC 125 monoclonal antibody based) assay for the quantification of tumor associated mucin-like CA 125 molecules present in the serum. Commercial kits, now supplied by various manufacturers (and in different versions, e.g. IRMA, EIA, etc.) are currently widely applied in the following clinical situations: (i) Monitoring of disease. Doubling or halving of CA 125 serum values correlated (in 87% of all cases) with tumor progression or regression, respectively. (ii) Early prediction of outcome. Deviation from the ideal CA 125 regression curve predicts poor outcome within 3 months of cytostatic treatment. (iii) Tumor status after completion of therapy. Patients with CA 125 > 35 U/ml have (in 95% of all cases) still tumor present (at second look surgery). However, patients with CA 125 < 35 U/ml have in 50% (mostly minimal) residual disease. (iv) Early detection of recurrence. After a complete remission, a rise in CA 125 precedes tumor recurrence in 75% of all patients, with lead times up to more then 1 year, surpassing the CT-scan in cheapness and accuracy. (v) Diagnosis and differential diagnosis. Only when used in combination with other markers, do CA 125 determinations have a value as a diagnostic adjunct in the discrimination of ovarian cancer patients from those with benign ovarian tumors and from those with advanced colon cancer. Today, optimal management of ovarian cancer patients can only be provided using the CA 125 serum test.

Use of Serum Tumor Markers in the Differential Diagnosis between Ovarian and Colorectal Adenocarcinomas

In the search for a method to facilitate the preoperative discrimination of ovarian carcinomas from colorectal carcinomas serum levels of 6 tumor markers were measured in 47 patients presenting with ovarian cancer and compared to levels found in 24 female patients with advanced, untreated colorectal cancer. The markers studied were CA 125, CA 15.3, CA 19.9, CEA and two recently developed mucin markers, CA M29 and CA M26. Levels of CA 125, CA 15.3, CEA and CA M29 showed significant differences between both groups. In predicting ovarian cancer, sensitivity was highest for CA 125 at 94% (35 U/ml cutoff level). However, the specificity of CA 125 was at 71% low. Specificity increased significantly by using a combination of a CA 125-positive score (greater than 35 U/ml) and a simultaneous negative CEA score (less than or equal to 5 ng/ml) (specificity 100%, sensitivity 81%). A CA 125/CEA serum ratio greater than 25 resulted in the highest discriminative power with a specificity of 100% and a sensitivity of 91% resulting in an overall test accuracy of 94%. It is concluded that the serum tumor markers used, especially a combination of CA 125 and CEA, are helpful in the preoperative differential diagnosis between adenocarcinomas of ovarian and colorectal origin.

Maternal Serum CA125 and CA15-3 Antigen Levels in Normal and Pathological Pregnancy

Objective: To evaluate the value of maternal serum CA125 and CA15-3 concentrations for discriminating pathological from normal pregnancies. Methods: Serum samples from 120 women, in whom pregnancy outcome was pathological, i.e. spontaneous abortion, fetal death, intrauterine growth retardation, chromosomal and structural abnormalities, and (pre)eclampsia, were assessed for CA125 and CA15-3 and compared with levels found in 350 women with a normal pregnancy outcome matched for age and duration of pregnancy. Results: Maternal CA125 serum values were significantly higher in the first and the third trimester of pregnancy (median 23.0 and 21.0 U/ml; p < 0.00001 and p < 0.001, respectively), compared to those in the second trimester (median 14.0 U/ml), but not significantly different from those obtained in pathological pregnancies. Maternal serum CA15-3 values were significantly higher during the third trimester (median 26.0 U/ml) compared to the first and second trimester of pregnancy (median 14.0 and 15.0 U/ml; p < 0.0001); CA15-3 serum levels in normal and pathological pregnancies showed no significant difference. Conclusion: Maternal serum levels of CA125 are higher during the first and third trimester of pregnancy. CA15-3 maternal serum levels are higher during the third trimester compared to the first and second trimester. Maternal CA125 and CA15-3 serum levels showed no relation with a pathological outcome of pregnancy.

Quantification of MUC1 in breast cancer patients : A method comparison study

OBJECTIVE To compare the performance of four serum assays for the quantification of MUC1 in breast cancer patients. STUDY DESIGN A total of 282 serum samples were evaluated with two automated (Boehringer Mannheim Enzymun-Test CA 15-3 and Chiron ACS BR) and two manual assays (Centocor CA 15-3 radioimmunoassay [RIA] and Biomira Truquant BR RIA). Sera were obtained from healthy controls (n=50), patients with benign (n=25) and malignant breast disease (n=77) and patients with other malignancies (n=69). In addition, sera from pregnant women (n=56) and patients with liver cirrhosis (n=5) were included. RESULTS Intraassay coefficients of variation (C.V.s) were highest for the manual Centocor CA 15-3 assay (7.4% for values below 50 kU/l and 8.1% for values above 180 kU/l). Interassay C.Vs were highest for the manual Truquant BR assay (11.7% for the lower concentration values and 18.6% for the higher concentration values). False positive rates ranged between 0% for the Centocor CA 15-3 RIA and 14% for the ACS BR assay (cut-off: 30 kU/l). In monitoring breast cancer patients all four assays show similar patterns, although absolute MUC1 values found may differ up to 50%. CONCLUSION For monitoring purposes all assays perform equally well, however, automated assays show lower inter- and intraassay variability, especially in the higher value range. Therefore we recommend the use of the same, automated, assay for quantification of MUC1 during the follow-up of breast cancer patients.

Mucin-Like Carcinoma-Associated Antigen Serum Levels in Patients with Adenocarcinomas Originating from Ovary, Breast and Colon

The mucin-like carcinoma-associated antigen (MCA) enzyme immunoassay was tested in 962 healthy controls. MCA levels were compared with CA 125 in 70 patients with benign and 76 with malignant ovarian tumors. In addition MCA was compared with CA 15.3 in 58 patients with breast cancer and with CEA in 50 patients with colon carcinoma. In healthy controls the 95th percentile cutoff of 19.2 U/ml appeared to be higher than generally used. With the common cutoff value of 14 U/ml, a 38% sensitivity and 100% specificity was reached in malignant versus benign ovarian tumors. In colorectal cancer only 4% of patients had elevated MCA serum levels (CEA: 50%). In breast cancer patients the MCA assay performed better than CA 15.3 although only 17.2% showed elevated levels (CA 15.3: 7.4%). Thus MCA seems to be of limited value in the diagnosis and follow-up of adenocarcinomas of breast, ovary or colon.

Clinical Relevance of the Tumor Marker CA 15.3 in the Management of Cancer Patients

The CA 15.3 serum assay, originally developed for the management of breast cancer patients has been evaluated in various groups of cancer patients for its applicability in clinical practice. This paper reviews the data from the literature addressing the issue of the usefulness of CA 15.3 in the management of cancer patients.

Evaluation of the Serum Markers CA 125, CA 15.3 and CA M29 in Monitoring Ovarian Cancer

In ovarian cancer, known as the »hidden« tumor, difficulties are encountered in the evaluation of the effectiveness of therapy and in diagnosing progressive or recurrent disease at an early stage. Given the tumor’s distinctive pattern of spread over serosal surfaces, advanced ovarian cancer is frequently associated with multiple small metastatic tumor deposits which stud the parietal and visceral peritoneum [7]. Small residual tumor nodules cannot be detected by the most careful gynecological or general physical examination nor by the most sophisticated methods like computerized tomography [2]. Chemotherapy therefore may be given for several months without knowing whether the residual tumor is regressing or progressing. In this setting a tumor marker, which accurately reflects tumor burden, would improve the management of ovarian cancer by preventing ineffective treatment mostly accompanied by severe toxicity.