[Intraoperative pleural lavage in lung cancer patients]

In lung cancer patients, pleural effusion may or may not be present even if cancer cells have invaded the pleura. Using the traditional staging methods, not all pleural metastasis can be detected before the presence of pleural effusion. We performed intraoperative pleural lavage on 38 patients who underwent a thoracotomy due to tumors of the lungs. The first lavage (lavage 1) was performed just after the pleural cavity was open; the second lavage (lavage 2) was performed after all surgical procedures were completed (including lung resection and mediastinal lymph node dissection). Totally 12 of the 32 primary lung cancer patients were found to have positive lavage 1 cytology; 13 had positive lavage 2 cytology. In 13 patients whose visceral pleura was invaded by tumor, 11 had a positive lavage 1, 10 had a positive lavage 2. For prediction of positive lavage 1 cytology from visceral pleural involvement, the accuracy was 90.6%, the sensitivity was 84.6%, the specificity was 94.7%, the positive predictive rate was 91.7%, the negative predictive rate was 90.0%. For lavage 2, the accuracy was 81.2%, the sensitivity was 76.9%, the specificity was 84.2%, the positive predictive rate was 76.9%, the negative predictive rate was 84.2%. Stage of disease and cell type seemed to have no relationship to the incidence of positive lavage fluid cytology. Further investigation is recommended to evaluate the prognosis of patients with positive lavage fluid cytology.