Controversy exists in using carcinoembryonic antigen (CEA) for monitoring the clinical course of breast cancer. In this study, the kinetics of two plasma tumor markers, CEA and CA15-3, immediately after the initiation of chemotherapy were assessed in 30 patients with advanced breast cancer. Four distinct kinetic patterns were seen. Two patterns fitted the expected relationship where the plasma marker increased during tumor progression (nine patients), and declined in tumor regression (five patients). The third pattern was paradoxical in that objective tumor regression in eight patients was associated with an acute surge of these markers followed by a steady decline. The doubling times for both CEA and CA15-3 were immediately shortened four-fold after therapy suggesting tumor cytolysis in treatment responders. Equally paradoxical was the fourth pattern where tumor progression in eight patients was associated with a rapid and transient decline of markers followed by rebounds. Such a rapid decline may be due to a suppression of marker release, as demonstrated in an in viiro study. Adequate knowledge of these putative paradoxical patterns will permit their effective use in monitoring the disease course and perhaps in the early prediction of the therapeutic response.
Cancer 65:193-199, 1990.
UMAN NEOPLASMS may express and release into the H circulation a variety of substances collectively referred to as tumor markers. Serologic analysis of these markers has been used in assessing the extent of disease and in monitoring the response to therapy. There are, however, contradicting views regarding the usefulness of blood carcinoembryonic antigens (CEA) in monitoring the clinical course of breast cancer. It is generally accepted that an increase or decrease of the CEA level may reflect the status of disease progression or regression, respectively. 1-6 Nevertheless, recent literature discourages the routine use of the CEA assay with the contention that it does not lead to more effective treatmenq7 and that CEA changes are too inconsistent to be used in clinical practice.8 About 50% of patients had a change in their CEA levels that conflicted with their clinical courses, such as an increase of CEA in patients with tumor regression or vice versa.
It is reasonable to assume that a similar controversy may arise for other newly developed markers, such as