Different cutoff values of Cyfra 21-1 for cavitary and noncavitary lung cancers

Study objectives: Cell lysis and tumor necrosis release cytokeratin, a tumo r marker of lung cancer, into the serum. The serum cytokeratin level can al so be elevated in benign cavitary lung diseases. The purpose of this study was to evaluate whether Cyfra 21-1 can differentiate malignant lung disease s from benign diseases with cavitary lesions. Design: This study is a retro spective review of the case records of patients with lung lesions seen duri ng a 4-year period from January 1993 to May 1996. Setting and patients: Ser um Cyfra 21-1 levels were measured in 306 patients with lung cancer (n = 14 3) or benign lung disease (n = 163). The patients were grouped according to radiologic evidence of cavitary lung lesions. Lung cancer included both no n-small cell (n = 123) and small cell (n = 20) lung cancers, and the benign diseases include tuberculosis (n = 87), abscess (n =26), pneumonia (n =4), and others (n = 46). Measurements and results: Although Cyfra 21-1 clearly differentiated cavitary lung cancer (15.0, 9.1-29.8 ng/ml, median and inte rquartile range, n = 39) from benign cavitary disease (P < 0.001), and nonc avitary lung cancer from benign noncavitary; disease (1.7, 0.9-2.6 ng/ml, n = 108, P < 0.001), it could not differentiate noncavitary lung cancer (5.0 , 2.1-12.4 ng/ml, n = 104) from benign cavitary diseases (3.3, 1.4-8.3 ng/m l, n = 55, P = 0.45). Conclusions: Serum Cyfra 21-1 is a useful tumor marke r for differentiating benign from malignant lung diseases. However, differe nt cutoff values are needed, depending on the presence of cavitary lesions. We recommend cutoff values of 30 ng/ml for cavitary lung diseases and 6 ng /ml for noncavitary lung diseases. If there are no radiologic data, a cutof f value of 15 ng/ml is recommended. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.