Kinetics of Serum Tumor Marker Concentrations and Usefulness in Clinical Monitoring

Abstract

Only a few markers have been instrumental in the diagnosis of cancer. In contrast, tumor markers play a critical role in the monitoring of patients. The patient’s clinical status and response to treatment can be evaluated rapidly using the tumor marker half-life (t1/2) and the tumor marker doubling time (DT). This report reviews the interest of determining these kinetic parameters for prostate-specific antigen, human chorionic gonadotropin, α-fetoprotein, carcinoembryonic antigen, cancer antigen (CA) 125, and CA 15-3. A rise in tumor markers (DT) is a yardstick with which benign diseases can be distinguished from metastatic disease, and the DT can be used to assess the efficacy of treatments. A decline in the tumor marker concentration (t1/2) is a predictor of possible residual disease if the timing of blood sampling is soon after therapy. The discrepancies in results obtained by different groups may be attributable to the multiplicity of immunoassays, the intrinsic characteristics of each marker (e.g., antigen specificity, molecular heterogeneity, and associated forms), individual factors (e.g., nonspecific increases and renal and hepatic diseases) and methods used to calculate kinetics (e.g., exponential models and timing of blood sampling). This kinetic approach could be of interest to optimize patient management.

CA 125 half‐life breakpoint between a “good” and “poor” prognosis in patients with ovarian cancer

“…CA 125 serum concentration is usually adopted to evaluate the clinical situation in ovarian cancer patients [2]. An approach to rapid evaluation of clinical response and monitoring, instead of using the coarse CA 125 serum concentration, is the determination of tumor marker kinetic parameters, associated with changes in its concentrations, such as half‐life ( t 1/2 ) and doubling time (DT) [3]. The rate of decline in CA 125 during primary chemotherapy has been an important independent prognostic factor in several multivariate analyses [2].…”

“…The rate of decline in CA 125 during primary chemotherapy has been an important independent prognostic factor in several multivariate analyses [2]. Several studies report the greatest difference in progression rate, found at a t 1/2 of 20 days while the normal CA 125 half‐life value to be determined varied from 5 to 10 days [3,4].…”

A retrospective cohort study of metastatic colorectal cancer patients treated with oxaliplatin‐based chemotherapy, with an exploratory analysis of changing serum carcinoembryonic antigen levels

“…It would be valuable to perform a prospective study to analyze the CEA response in patients with metastatic colorectal cancer, undergoing palliative chemotherapy, in order to address the predictive and prognostic importance of CEA in those on treatment. Tumor markers such as CA125 for ovarian cancer, PSA for hormone‐sensitive prostate cancer and alpha fetoprotein for testicular cancer are well established in monitoring patients on therapy 19–21,25,26 . Perhaps with more supporting data, CEA for metastatic colorectal cancer can be added to this list.…”

Serum concentrations of HE4 change little during in vitro fertilization

“…CA125 and estradiol (E2) concentrations were measured using electro‐chemiluminescence immunoassay. The upper normal level for CA125 was considered 35 U/mL as widely used in clinical practice .…”