BACKGROUNDTo explore a rapid and accurate method for examining cancer cell from the sputum in patients with lung cancer.

METHODSOne hundred and twenty patients with lung cancer diagnosed by operation and pathologically confirmed were enrolled in this study. Sputum sediment section and sputum smear examinations were performed and compared for diagnosis of lung cancer.

RESULTS(1) The positive rate of lung cancer cell was 71.67% (86/120) by sputum sediment section examination, however, only 31.67% (38/120) by sputum smear examination ( P < 0.001). The diagnostic rate of combination of two methods for lung cancer was 90.83% (109/120), which was significantly higher than that of single sputum sediment section examination ( P < 0.001). (2) With routine HE staining, 55 patients (55/86,63.95%) could be histologically identified by sputum sediment section examination, but only 6 patients (6/38,15.79%) by sputum smear examination ( P < 0.001). (3) In 31 patients unidentified with routine HE staining, 29 were further histologically confirmed by sputum sediment section examination with immunohistochemistry.

CONCLUSIONSCompared to sputum smear examination, sputum sediment section examination can make use of more sputum materials, show a higher sensitivity for cancer cell, and accurately identify the histological classification of tumor. It is supposed to be a good examination for lung cancer and deserved to be extended in clinical application.