Sa1431 Minimally Invasive Sampling of Abnormal PET Targets by EUS-Guided FNA Improves Clinical Staging of Patients With Suspected Non-Small Cell Lung Cancer (NSCLC)

Minimally Invasive Sampling of Abnormal PET Targets by EUSGuided FNA Improves Clinical Staging of Patients With Suspected Non-Small Cell Lung Cancer (NSCLC) James P. Callaway, Ashutosh Tamhane, Gurudatta Naik, Ayesha S. Bryant, Whitney Jennings, Robert J. Cerfolio, Mohamad A. Eloubeidi Internal Medicine, University of Alabama at Birmingham, Birmingham, AL; Gastroenterology, University of Alabama at Birmingham, Birmingham, AL; Biostatistics, University of Alabama at Birmingham, Birmingham, AL; Cardiothoracic Surgery, University of Alabama at Birmingham, Birmingham, AL Background: Current guidelines recommend that all abnormal lesions by PET scan should be sampled prior to thoracotomy in patients with lung cancer. EUSFNA has been demonstrated to be safe and minimally invasive in diagnosing N2/ N3 and metastatic disease to the adrenal glands. We currently report our updated large experience to determine the role of EUS-FNA in identifying abnormal PET scan lesions. The secondary objective was to determine predictors of lymph node malignancy. Methods: Consecutive patients (N 282) who underwent both PET and EUS-FNA between June 2003 and June 2009 at a tertiary care teaching hospital were evaluated. Targets sampled by EUS included: the adrenal glands and/or (N2/N3) stations 9, 8, 7, 5, 4L, or 2. All EUS examinations were performed by a single endosonographer. The reference standard included surgery or clinical follow-up ( 6 months). Abnormal PET targets were defined by a maximum standardized uptake value (SUV) of 2.5. Results: Mean age was 66 years and 66% were men. Mediastinal lymph nodes were solely sampled in 243 patients, while only Stage IV lesions in 18 and both in 21. In the 264 patients who underwent EUS-FNA of lymph nodes, sensitivity, specificity, positive predictive value, negative predictive value, accuracy, of EUS-FNA were: 76%, 100%, 100%, 81%, 88% respectively and for PET: 84%, 53%, 64%, 78%, 69%, respectively for confirming N2/N3 disease. EUS-FNA confirmed PET staging in 168 patients while 63 were “downstaged” (25.8%) and 11 “upstaged” (4.1%); 22 patients were falsely downstaged by EUS-FNA. In 11 patients with false negative FNA results, the node was not routinely accessible by EUS. In multivariable analysis, the short axis of the lymph node by EUS (ORadjusted1.25; 95% CI: 1.091.44; p 0.002) and SUV of the lymph node (ORadjusted1.38; 95% CI: 1.12-1.69; p 0.002) were significant predictors of malignancy when adjusted for age, race, sex, lymph node long axis, primary mass SUV and location, and prior chemotherapy. EUS-FNA confirmed Stage IV lung cancer in 19 patients (1 gastrohepatic node, 1 perigastric node, 1 pancreas, 3 right adrenals and 13 left adrenals) and in 1 patient who had left adrenal involvement without PET uptake. Conclusions: EUS-FNA improved clinical staging in patients with suspected NSCLC. Its ability to accurately confirm the nature of abnormal PET scan targets, along with the ability to upstage and downstage false positive and false negative PETs, makes it an ideal choice for initial minimally invasive sampling. Lymph node short axis and lymph node SUV were the significant predictors of malignancy and may help guide endosonographers to which lymph node needs to be sampled first during EUS.