Serum levels of CYFRA 21-1 in nasopharyngeal carcinoma and its possible role in monitoring of therapy.

CYFRA 21-1 is a fragment of cytokeratin expressed by simple epithelia and their malignant counter-parts. Serum CYFRA 21-1 levels were studied in 240 new cases of nasopharyngeal carcinoma and 19 patients who developed distant metastases. A reference range of < 2 U/ml for our local Chinese population was established in 55 sex- and age-matched healthy volunteers. The nasopharyngeal carcinoma patients had significantly higher marker levels than the healthy controls and the mean level increased with advancing stage. However, the low percentage of elevation in early stages means that the marker is not useful for screening. The overall percentage (52.5) of elevation in 240 newly diagnosed squamous cell carcinoma of the nasopharynx is comparable to that of squamous cell carcinoma of the lungs, suggesting that the expression of CYFRA 21-1 is related to the cell type rather than the tissue type of the carcinoma, 46 (95.8%) of 48 patients with metastatic nasopharyngeal carcinoma showed an elevated value of CYFRA 21-1. This extremely high percentage implies that it is very unlikely for a patient with a normal value to have distant metastasis. This may permit major economies in radiological screening for distant metastasis. Preliminary results from serial measurement of the marker indicated its potential for monitoring response to treatment and for early detection of distant metastasis.