Immunocytochemical staining for CEA in small cell carcinoma of lung predicts clinical usefulness of plasma assay

ABSTRACT

Recent studies have shown CEA levels useful in both staging and monitoring response to treatment in patients with small cancer of the lung [SCCL]. CEA elevations do not occur in all patients however, and have been of less value in patients with limited disease. Immunoperoxidase staining of CEA performed on tumor tissue from 48 patients [17 extensive, 31 limited disease] with SCCL revealed 1] A strong correlation between positive CEA tissue staining and plasma CEA elevation. Plasma CEA elevations occurred in 18/21 CEA tissue positive patients and correlated with the clinical course in all 18. In contrast elevated plasma CEA levels were seen only in 3/27 CEA tissue negative patients; 2] CEA tissue positive patients had a high incidence of extensive liver metastasis [43% versus 7%, 3]. No correlation between histologic subtype and CEA tissue staining was apparent