Plasma cea levels in small cell lung cancer. Correlation with stage, distribution of metastases, and survival

Abstract

Plasma CEA levels were determined in 61 patients with small cell lung cancer entering chemotherapy protocols between 1976 and 1980. Five quantitative categories were determined: less than 2.5 ng/ml (the standard normal for Hansen assay); 2.6–5.0 ng/ml (the extended normal for smokers); 5.1–20.0 ng/ml (the intermediate elevation and the transition for the indirect to the direct assay); 20–100 ng/ml; and greater than 100 ng/ml. Forty‐seven percent of patients had levels less than 5 ng/ml and only ten of 61 or 16% had levels greater than 20 ng/ml. There was no clearcut relationship of plasma CEA level to stage of disease, in that 40% of patients with extensive disease (32 patients) had levels less than 5 ng/ml and 45% of patients with limited disease (29 patients) had levels greater than 5 ng/ml. Similarly, there was no relationship of CEA level to site of metastases, although levels greater than 100 ng/ml were always associated with liver metastases. The median survival for each quantitative category was similar, ranging from seven to nine months. The use of sequential determinations of CEA to correlate with tumor response was studied in only eight patients with levels greater than 20 ng/ml and a measurable parameter of disease. The qualitative direction of change of CEA was appropriate in those patients responding to treatment but in three nonresponding patients the direction of CEA change paradoxically decreased. In five patients who developed progressive disease, the plasma CEA level predicted the clinical relapse. CEA as a tumor marker for oat cell carcinoma must be applied in conjunction with other tumor parameters and is meaningful in only a small proportion of the total small cell patient population.