Serum sialic acid (TSA/LSA) and carcinoembryonic antigen (CEA) levels in cancer patients undergoing radiotherapy

Abstract

The main aim of this study was to evaluate the response of total Sialic Acid (TSA) and "Lipid-bound" Sialic Acid (LSA) compared to Carcinoembryonic Antigen (CEA), in 284 patients undergoing radiotherapy. Serial measurements of TSA by the enzymatic method (Boehringer-Mannheim Kit), LSA by the resorcinol-HC1 (Katopodis and Stock) and CEA by EIA (Abbott Kit) were performed in a total of 1017 blood sera. We statistically estimated the four greater groups of cancer patients [bladder (69), lung (58), uterus (31) and breast (29)]. Diagnostic marker sensitivities (% true positives) estimated from the 0-time-values--before initiation of radiotherapy--in relation to the established cut-off levels were in decreasing order: TSA 89.3% (80 mg/dL). LSA 88.8% (20 mg/dL) and CEA 26.75% (5 ng/mL). The overall tumor marker response to treatment, after its completion, estimated as % of patients with final blood serum levels of these markers, was in decreasing order: LSA 85.6%, TSA 81.3%, and CEA 65.8%. These data show that a) the diagnostic sensitivity of Sialic Acid (LSA/TSA) is more than 3 times higher than that of CEA and b) the response of Sialic Acid (LSA/TSA) to treatment is about 15% higher than that of CEA. In conclusion, this study confirms the high diagnostic sensitivity of Sialic Acid as a tumor marker and suggests that, with marginal superiority of Sialic Acid, all three markers are sufficiently responsive to be employed as adjunctive means in monitoring cancer patients underdoing radiotherapy.