Serum fragment of cytokeratin subunit 19 (Cyfra) as a tumor marker in diagnosis and monitoring of treatment of oral squamous cell carcinoma

Background. There have been no reports describing effective methods for diagnosing, assessing prognosis, or monitoring the treatment of oral squamous cell carcinoma (O-SCC). However, fragment of cytokeratin subunit 19 (Cyfra) has been reported to be a new marker in non-small cell carcinoma of the lung. Cytokeratins are intermediate filaments which make up the cytoskelton of normal epithelia and their malignant counterparts. We undertook this study to determine the value of measuring serum Cyfra levels in patients with O-SCC. Methods. Cyfra was determined by a solid-phase immunoradiometric assay, based on a two-sandwich method, of sera from 50 patients with O-SCC, 20 patients with benign oral diseases, and 10 healthy controls. The O-SCC patients were allocated to two groups: a good-prognosis group (32 patients who were completely tumor-free for more than 3 years after primary treatment) and a poor-prognosis group (18 patients who all died due to either local recurrence or regional lymph node or distant metastasis). Serial measurements of Cyfra were available before treatment as well as during individual therapy and follow-up in 20 patients. Serum samples were obtained at the time of primary diagnosis and after treatment, and at least once postoperatively. Results. The mean serum concentration of Cyfra in patients with O-SCC (2.24 ± 2.55 ng/ml) was significantly higher than that in the 20 patients with benign oral diseases (1.38 ± 0.77 ng/ml) and in the 10 healthy controls (1.17 ± 0.41 ng/ml) (P < 0.01). The mean serum concentration of Cyfra was significantly lower in the good-prognosis group (1.76 ± 1.25 ng/ml) than in the poor-prognosis group (3.08 ± 3.83 ng/ml) (P < 0.01). When good control of the cancers was achieved, the serum level of Cyfra returned to normal. In most patients with a poor prognosis, serum Cyfra levels decreased after primary treatment, but still remained higher than the cut-off level (i.e., upper limit of normal, 2.0 ng/ml). Conclusion. Based on the above findings, Evaluation of Cyfra in O-SCC patients appears to be a valuable tool as a tumor marker for assessing prognosis and monitoring treatment of O-SCC. Received: November 28, 1996 / Accepted: June 29, 1998