ABSTRACT
This study was planned to assess the possible role a new tumor marker, cytokeratin fragment, Cyfra 21-1 in differentiating malignant and benign lung lesions in presence or absence of cavitation. This study included 30 patients with proved lung cancer [15 squamous cell carcinoma, 6 adenocarcinoma, 5 large cell carcinoma, and 4 small cell carcinoma] and 30 patients with proved benign lung disease [12 T.B., 10 pneumonia, and 8 lung abscess]. All patients were diagnosed as having cavitary or noncavitary lung lesions by chest X-ray and CT-scan. Lung cancer patients included [13 cavitary and 17 noncavitary disease], while benign lung disease included [14 cavitary and 16 noncavitary lesion]. Serum samples were obtained from a total of 60 patients and examined for Cyfra 21-1 by electro-chemiluminescence immunoassay. The results showed that serum cyfra 21-1 level was significantly higher in lung cancer patients [16.22 +/- 2.1 ng/ml] than in patients with benign lung disease [3.85 +/- 0.46 ng/ml]. Moreover, significant differences in the serum Cyfra 21-1 levels were observed between cavitary lung cancer [25.15 +/- 3.27 ng/ml] and benign cavitary lung disease [6.17 +/- 0.48ng/ml], and between noncavitary lung cancer [9.38 +/- 1.06 ng/ml] and benign noncavitary lung disease [1.83 +/- 0.12 ng/ml]. The results also showed a significant difference in the serum Cyfra 21-1 levels between noncavitary lung cancer [9.38 +/- 1.06 ng/ml] and benign cavitary lung disease [6.17 +/- 0.48 ng/ml]. Among lung cancer patients, the serum Cyfra 21-1 level was significantly higher in squamous cell carcinoma [24.13 +/- 2.89 ng/ml] than adenocarcinoma [10.70 +/- 1.43 ng/ml], large cell carcinoma [9.88 +/- 1.09 ng/ml] or small cell carcinoma [5.42 +/- 1.00 ng/ml]. The study showed that a cutoff value of serum Cyfra2l-l level>8 gives a sensitivity of 76% and a specificity of 93%. At a cutoff value of serum Cyfra21-1 of> 3 ng/ml, all patients with noncavitary cancerous lesions were differentiated from patients with noncavitary benign lesions. Also, at a cutoff value of serum Cyfra21-1 of>10 ng/ml, all patients with cavitary cancerous lesions were separated from patients with cavitary benign lesions. This study concluded that serum cyfra 21-1 is a useful marker for differentiating malignant versus benign cavitary and noncavitary lung lesions with greater sensitivity and specificity when different cutoff values are applied