Tumour lysis as a factor affecting blood levels of CEA

Abstract

A hypothesis is proposed that tumour lysis may be an important factor affecting blood levels of CEA. This has been explored in an experimental study with a model tumour system, consisting of immune-deprived mice bearing human CEA-producing tumours. Using agents such as irradiation, chemotherapeutic drugs, diphtheria toxin and techniques such as cryosurgery, it has been shown that tumour lysis is important when it is both rapid and extensive. The extent to which this may occur in patients remains uncertain, except in rare instances of dramatic response of malignant disease to treatment.

Phase I Trial of Intravenous Administration of PV701, an Oncolytic Virus, in Patients With Advanced Solid Cancers

“…In addition, immediately after dosing there was a spike in carcinoembryonic antigen level (approximately 4.5-fold increase) followed by a drop to steady-state levels at 79% below baseline, shown elsewhere to be further indicative of a response. 27 Progression-free survival of 10 months was observed in this patient. Seven other patients with diverse malignancies (including mesothelioma, melanoma, colon carcinoma, breast carcinoma, pancreatic carcinoma, and carcinoid) had measurable tumor reduction, although less than 50% of the total tumor burden.…”

Tissue concentrations of CEA and CA 19-9 in the carcinogenesis of colorectal carcinoma exemplified by the adenoma-carcinoma sequence

“…To date, the factors on which the active or passive release of tumor antigens out of tumor tissue depends, still remain unknown. Such different factors as the vascularity of the tumor [12,13], the extent of tumor necrosis [14], the activity of the tumor cells as measured by the number of mitotic figures [15], or tumor differentiation [16] and the DNA profile [17], are still under discussion. In view of these partly unexplained relationships, the measurement of tumor-associated antigens within the tissue is rightly considered to be far more specific.…”

Calculation of half-life of carcinoembryonic antigen after lung tumour resection: a case report

“…Since a reduction in carboanhydrate components make CEA molecules less resistant to degradation, they are cleared at a rate inversely related to their carboanhydrate content [4). By analogy, we therefore suggest that the rapid initial fall of CEA in our patient could have resulted from rapid clearance of "non-secretory" CEA directly released from the tumour during the operation (9].…”