Pleural lavage cytology immediately after thoracotomy as a prognostic factor for patients with lung cancer.

Pleural lavage cytology was examined in 230 lung cancer patients just after opening the chest. There were 16 cases (7.0%) of positive pleural lavage cytology, and the results of pleural lavage cytology were related to the presence of pleural involvement by cancer, microscopical pleural dissemination and lymphatic permeation of the cancer cells. If the cancer involves the pleura or lymphatics of the submesothelial layer, being covered with visceral mesothelium, positive cytology may still be obtained. Pleural lavage cytology at opening of the chest seems to be available as a premonitory indicator for exfoliation and dissemination into the pleural cavity or subpleural lymphatic extension of cancer cells, and it was suggested that positive pleural lavage cytology has an influence on postoperative survival.