Interpretation of Sequential Measurements of Cancer Antigen 125 (CA 125), Carcinoembryonic Antigen (CEA) and Tissue Polypeptide Antigen (TPA) Based on Analytical Imprecision and Biological Variation in the Monitoring of Ovarian Cancer

• Published in: Clinical chemistry and laboratory medicine Vol. 39; no. 6; pp. 531 - 538
• Main Authors: Tuxen, Malgorzata K., Sölétormos, György, Petersen, Per Hyltoft, Dombernowsky, Per
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin Walter de Gruyter 01.06.2001; New York, NY
• Subjects: Adult; Aged; Analysis of Variance; Biological and medical sciences; Biometry; CA-125 Antigen - blood; Carcinoembryonic Antigen - blood; Female; Female genital diseases; Gynecology. Andrology. Obstetrics; Humans; Immunoassay - standards; Immunoassay - statistics & numerical data; Longitudinal Studies; Medical sciences; Middle Aged; Ovarian Neoplasms - diagnosis; Ovarian Neoplasms - immunology; Quality Control; Reference Values; Tissue Polypeptide Antigen - blood; Tumors; Human; Concentration factor; Variability; Tissue polypeptide specific antigen; Tumoral marker; Malignant tumor; Female genital diseases; Ovarian diseases; Carcinoembryonic antigen; Ovary; Surveillance; CA 125 antigen; Female
• ISSN: 1434-6621
• DOI: 10.1515/CCLM.2001.089

The main objective with cancer antigen 125 (CA 125), carcinoembryonic antigen (CEA), and tissue polypeptide antigen (TPA) monitoring of ovarian cancer patients is to detect an early change of disease activity with high reliability. We hypothesized that a monitoring scheme for ovarian cancer patients with serological tumor markers should take into account the stochastic variation, i.e. the probability that observed increases and decreases may solely be due to analytical imprecision and normal intra-individual biological variation. The aim of this study was to provide a detailed characteristic of the within-subject mean steady state concentrations and the associated variability in healthy individuals with an age distribution representative for ovarian cancer patients. Thirty-one healthy women with a median age of 55 years comprised the study population. Sixteen blood samples were collected from each subject in four series, with four samples per series, over a period of approximately 1 year. We found that, i) natural logarithmic-transformed concentrations were more homogeneously distributed between individuals than the original concentrations, ii) the within-subject mean steady state levels, the standard deviations, and the coefficients of variation differed among subjects, and iii) the steady state variability differed among the markers. In conclusion, our data indicate that the assessment of sequential CA 125, CEA, and TPA concentrations is more complex than hitherto recognized. We suggest that it is necessary to adjust the assessment criteria to the type of marker, and that assessment may be facilitated if based on natural logarithmic transformed concentrations.