Accuracy of EUS in staging of T4 lung cancer Shyam Varadarajulu, MD, Nathan Schmulewitz, MD, Stephan F. Wildi, MD, Stacey Roberts, MD, James Ravenel, MD, Carolyn E. Reed, MD, Mark Block, MD, Brenda J. Hoffman, MD, Robert H. Hawes, MD, Michael B. Wallace, MD, MPH Charleston, South Carolina Background: Increasingly, EUS is being used to stage lung cancer. Direct mediastinal invasion (T4) by lung cancer is stage IIIb disease. Patients in this stage have a 5-year survival of less than 5% and generally are offered chemotherapy without surgery. This study evaluated the accuracy of EUS in detecting T4 lung cancer. Methods: The study included all patients with lung cancer who had EUS staging and subsequent staging at surgery, or for whom there was unequivocal confirmation of unresectability (T4) by thoracoscopy, thoracotomy or presence of malignant pleural effusion, or definite invasion of great vessels/adjacent organs on CT. Results: A total of 175 of 308 patients with lung cancer who underwent EUS over a 5-year period (1997-2002) had subsequent confirmatory tumor staging. Ten patients were found by EUS to have stage T4 tumors; 7 were confirmed to be T4 by either surgical exploration (2), CT demonstration of aortic invasion (3), or documentation of malignant pleural effusion (2). Three of the 10 (30%) patients found to have stage T4 tumors by EUS had T2 disease at surgery and underwent curative resection. Of the remaining 165 patients without evidence of T4 disease at EUS, only one was found to have aortic invasion (T4) at surgery. EUS had a sensitivity of 87.5%, specificity of 98%, positive predictive value of 70%, and a negative predictive value of 99% for detecting T4 disease. Conclusions: Caution is warranted when unresectability of lung cancer is based solely on tumor invasion into mediastinal soft tissue at EUS. Overstaging occurs when a tumor appears to invade the pleural layer without mediastinal organ invasion. Confirmation of unresectability by other diagnostic modalities is warranted in such instances. (Gastrointest Endosc 2004;59:345-8.) Lung cancer is the leading cause of cancer death in both men and women; in the United States, the overall 5-year survival rate for patients is approxi- mately 15%. 1 Treatment is based on the extent of disease, location of the primary tumor, and the presence or absence of comorbid disorders. A staging system for lung cancer has been developed by the American Joint Committee on Cancer. 2 Patients without mediastinal invasion (stages I and II) are potential candidates for surgical resection. Unfortu- nately, nearly 30% of patients with lung cancer harbor mediastinal disease at presentation. Direct mediastinal invasion (T4) is classified as stage IIIb disease. Patients in this stage have a 5-year survival rate of less than 5% and generally are offered chemotherapy without surgery. Although designed for the local staging of GI cancers, EUS provides excellent access to the pos- terior mediastinum through the esophageal wall. 3 Initial studies in patients with lung cancer and posterior mediastinal adenopathy on CT demon- strate EUS-guided FNA (EUS-FNA) to be superior to CT for detection of malignancy, with a sensitivity and specificity of, respectively, 90% and 100%. 4-7 Al- though the accuracy of EUS for evaluating medias- tinal adenopathy in lung cancer is established, its accuracy for detection of T4 disease per se has not been reported. Our experience with EUS for detect- ing T4 disease in lung cancer was reviewed to assess the accuracy for diagnosis and staging. PATIENTS AND METHODS An EUS database was queried for all patients with lung cancer who underwent staging EUS between January 1998 and June 2002 at our tertiary referral center. Pa- tients enrolled in the database were referred for EUS for mediastinal staging after a tissue diagnosis was made by CT-guided biopsy or bronchoscopy. However, in a small minority of patients with suspected lung cancer, a tissue diagnosis was established at EUS. Thus, for all patients included in the database, there was a confirmatory tissue diagnosis. In our institution, patients with lung cancer and obvious chest wall invasion, large pleural effusion, or metastatic disease do not undergo EUS staging. As part of an Received September 3, 2003. For revision September 24, 2003. Accepted October 28, 2003. Current affiliations: Digestive Disease Center, Medical University of South Carolina, Charleston, South Carolina. Meeting presentation: Digestive Diseases Week, May 18-21, 2003, Orlando, Florida (Gastrointest Endosc 2003;57:AB240). Reprint requests: Shyam Varadarajulu, MD, Division of Gastro- enterology-Hepatology, University of Alabama at Birmingham, ZRB 633, 1530 3rd Ave. S, Birmingham, AL 35294-0007. Copyright Ó 2004 by the American Society for Gastrointestinal Endoscopy 0016-5107/$30.00 PII: S0016-5107(03)02541-0 VOLUME 59, NO. 3, 2004 GASTROINTESTINAL ENDOSCOPY 345