<p num="52">FIELD: medicine.</p> <p num="53">SUBSTANCE: present invention refers to medicine, namely to a method for screening of malignant tumors of thoracic cavity organs, including determination of exhaled air composition by non-selective method of analyzing volatile organic compounds using metal oxide sensors with cross sensitivity, characterized by that analysis of volatile organic compounds is carried out with simultaneous use of 7 metal oxide chemoresistive gas sensors at successively installed temperatures of 350, 400 and 450 °C and additionally performing sputum cytological analysis with manufacture and microscopic examination of 2 micropreparations, which are stained with hematoxylin and eosin, and when observing in the sensor response to the exhaled air composition statistically significant differences from the reference values determined in advance for the sensors used, and simultaneous detection in micropreparations of dysplasia and cancer cells, a malignant tumor is diagnosed.</p> <p num="54