CEA in tumors of other than colorectal origin

Carcinoembryonic antigen has been demonstrated to be a valuable clinical aid in the management of patients with colorectal carcinoma. Its elevation in the serum prior to evidence of clinical recurrence in up to 80% of patients highlights its utility. CEA has also been found to be elevated in the serum of patients with other epithelial malignancies, but these have not been as well studied as has colorectal carcinoma. In patients with breast cancer CEA elevations may be found in 40-73% of patients presenting with disease in stages I-IV. In addition, 80% of patients will have a CEA elevation 3-10 months prior to clinical symptoms of recurrence. Seventy-seven percent of patients with bronchogenic lung cancer will have an elevated preoperative value. However, cigarette smoking also causes an increase in the CEA assay level and, thus, differentiation between benign and malignant conditions is more difficult. In small cell carcinoma of the lung, CEA assay levels above 10 ng/ml correlate highly with metastatic disease, while values less than 2.5 ng/ml correlate with localized disease. Pancreatic and gastric malignancies demonstrate CEA level elevations in just over 50% of cases. But these, however, have not been clinically useful. Epithelial neoplasms of the female reproductive tract (cervix, uterus, and ovary) also produce CEA in 47-75% of cases and may correlate with stage of disease at diagnosis and level of cellular differentiation. CEA assay levels are elevated in a variety of tumors and correlate with tumor stage, degree of differentiation, and effectiveness of therapy; they may also be the earliest marker of recurrence.