Diagnostic value of chest radiography, computed tomography and tumour markers in the differentiation of malignant from benign solitary pulmonary lesions.

Background: The aim of this prospective study was to assess the diagnostic value of the imaging modalities (chest radiography, spiral computed tomography (SCT) and high-resolution computed tomography (HRCT)) and the tumour markers (carcinoembryonic antigen (CEA), cytokeratin marker (CYFRA 21-1) and neuron-specific enolase (NSE)) in the differentiation of malignant (MSPLs) from benign solitary pulmonary lesions (BSPLs).

Patients And Methods: Solitary pulmonary lesions (SPLs) were examined, evaluated and then completely removed by surgery in 104 consecutive patients (MSPLs n = 81, BSPLs n = 23). Chest radiography was performed with frontal and lateral views, SCT was carried out with a slice thickness of 8 mm and HRCT with a slice thickness of 1 mm and a 12-cm field of view. For the tumour marker analysis, serum concentrations were determined 1-3 days prior to surgery by ELISA for CEA and CYFRA 21-1 and by IRMA for NSE using commercially available assay kits. The cut-off values were set at 3 ng/ml (for non-smokers) and 5 ng/ml (for smokers) for CEA, at 3.3 ng/ml for CYFRA 21-1 and at 12.5 ng/ml for NSE.

Results: Using any one of the characteristics with a significance level of P <0.01, the identification of MSPLs using chest radiography showed a sensitivity of 64.2% and a specificity of 82.6%, using SCT a sensitivity of 88.9% and a specificity of 60.9% and using HRCT a sensitivity of 91.4% and a specificity of 56.5%. For the identification of MSPLs using CEA a sensitivity of 27.2% and a specificity of 87.0% (accuracy of 40.4%) was observed. Using CYFRA 21-1 a sensitivity of 19.8% and a specificity of 100.0% (accuracy of 37.5%) and using NSE a sensitivity of 13.6% and a specificity of 100. 0% (accuracy of 32.7%) was found.

Conclusions: Using chest radiography, SCT and HRCT, a precise morphological assessment of the periphery of the pulmonary lesion and the adjacent visceral pleura is necessary to distinguish MSPLs from BSPLs. Tumour markers used alone or in combination with the imaging methods brought no additional benefits, in terms of sensitivity and accuracy, over the diagnostic imaging methods alone. However, the tumour markers exhibited a far superior specificity (100% for CYFRA 21-1 and NSE) compared with the imaging methods.