Impact of Renal Functional Impairment on Serum Tumor Markers Levels

Objective: To study the impact of renal functional impairment on the circulating levels of alpha- fetoprotein (AFP), carcinoembryonic antigen (CEA), and cancer antigen 19-9 (CA-19-9). Relevance: A challenging approach to rapid evaluation of clinical response and monitoring anti-cancer therapy is the determination of kinetic parameters associated with changes in tumor marker concentrations. During follow-up of patients with neoplastic disease, causes of nonspecific increases in tumor marker concentrations should be defined and be taken into consideration to avoid the unnecessary exposure of patients to the potential toxic side effects of the treatment. A variety of renal diseases may be associated with various malignancies or with treatment of malignancy with chemotherapeutic drugs or radiation. Renal diseases may also affect the kinetics of tumor markers because this tissue is involved in their metabolism. Methodology: 51 subjects were enrolled in the study. They were divided into three groups; the first group consisted of 13 apparently healthy volunteers (5 males 8 females) as a control group, the second one included 17 patients with end stage renal failure (ESRF) (8 males 9 females), and the third group comprised 21 patients (12 males 9 females) with ESRF maintained on haemodialysis (HD). Tumor marker determinations were performed using enzyme-linked immunosorbent assay. Data management and analysis were performed using Statistical Analysis Systems. Data were summarized using means and standard deviations. Comparisons between groups were done using Kruskall-Wallis, nonparametric analysis of variance. To measure the strength of the association between two numeric variables, Pearson s correlation coefficient was computed. All p-values are two-sided. p-values 0.05 were considered significant. Study validation: Semm CEA (ng/ml) and CA-19-9 (U/ml) values showed significant elevation in patients with ESRF (5.2±3.1 and 57.8±31.1, respectively, p = 0.001) and HD patients (4.9±2.5 and 64.0±68.5, respectively, p 0.001) as compared to healthy subjects (2.2±0.8 and 5.3±2.3, respectively), with insignificant difference between both diseased groups. Serum AFP levels, on the other hand, was insignificantly changed in patients as compared to healthy subjects. 47% and 48% of patients with ESRF and those maintained on HD, respectively, showed serum CEA concentrations 4ng/ml. 59% and 52% of patients with ESRF and those maintained on HD, respectively, showed serum CA 19-9 levels 37U/ml. 375 Conclusions: Our results suggested that renal functional impairment should be added to the list of benign conditions associated with high serum CEA and CA 19-9 levels. Before interpreting a tumor marker result in a patient with compromised renal function, we have to bear in mind that renal impairment might induce a misleading tumor marker elevation. The lack of significant correlation between elevated serum tumor marker values and serum creatinine and/or urea, and the observed normal serum AFP values raises many questions about the exact mechanisms responsible for increased some tumor markers levels in uremia. The recorded conflicting results of serum tumor markers in uremia indicated that the study of tumor marker kinetics in uremic patients deserves a more considerable attention.