Multiple biologic markers in the monitoring of treatment for patients with small cell carcinoma of the lung: The use of serial levels of plasma cea and serum carbohydrates

The monitoring utility of serial patterns of a single marker (carcinoembryonic antigen) level and multiple marker (three carbohydrates—fucose, mannose and galactose) levels in patients with small cell carcinoma of the lung was investigated using a quantitative approach. A serial multiple regression (SMR) model was formulated to assess the disease responses following the first to the tenth course of therapy and resulted in the multiple correlations ranging from 0.183 (NS)–0.706 (P < 0.005) for CEA, and 0.502 (P < 0.250)–0.760 (P < 0.025) for three carbohydrates, respectively. The appraisal of these markers utilizing the SMR model points out that: (1) the serial levels of CEA >5.0 ng/ml are significantly correlated with the disease course whereas the serial levels <5.0 ng/ml reflect the trend of variation in the disease course, but with less accuracy; and (2) the levels of three carbohydrates, any one elevated before and during therapy, are significantly correlated with the disease course.