Diagnosis of Visceral Pleural Invasion in Resected Lung Cancer Using a Jet Stream of Saline Solution

Background. Visceral pleural invasion by the tumor is an important prognostic factor in patients undergoing resection for lung cancer. We developed a method to detect more accurately the presence of visceral pleural invasion in resected lung cancer. Methods. The surface of the visceral pleura over 90 resected peripheral tumors was irrigated twice with a jet stream of saline solution using a 20-mL syringe with a 21-gauge needle, and then the fluid, which contained desquamated cells, was collected for cytologic analysis. When cancer cells were found in the collected fluid, the tumor was judged to have invaded the visceral pleura. Results. Thirty-eight (42%) resected tumors were identified as having visceral pleural invasion either by our new method or by pathologic examination. Twenty-four cases were detected by the jet stream of saline method alone, 5 by pathologic examination alone, and 9 by both techniques. The sensitivity and accuracy of the two approaches in the diagnosis of visceral pleural invasion were 87% and 94%, respectively, for our new method, and 37% and 73%, respectively, for pathologic examination (p < 0.0001). Furthermore, among 38 patients who had a tumor demonstrating visceral pleural invasion, 5 (13%) and 9 (24%) patients, respectively, had cancer cells in the pleural effusion and intrapleural lavage fluid. Conclusions. Our findings suggest that our method is useful in detecting cancer invasion of the visceral pleura, which is considered one of the causes of malignant effusion.