P1.05-15 Benign Lung Nodule Resections in the Era of Advanced Imaging and Clinical Guidelines: Imaging Features and How we can Reduce the Resection Rate

Abstract

Evaluation of lung nodules is a long standing clinical problem. Despite advances in diagnostics, many nodules are still resected that are benign. Although certain imaging characteristic can distinguish benign from malignant lung nodules on CT and PET/CT, overlap exists. Our purpose is to understand the benign resection rate with use of PET and PET/CT, and to review the patient and imaging characteristics of benign resected nodules in the PET-PET/CT era. We reviewed all 557 surgically resected lung nodules from 2001-2012. Patient demographics, smoking and cancer history, diagnostic tests prior to surgery, and pathology results were collected. All preoperative CT examinations were reviewed for nodule location, size, shape, border and attenuation, and PET/CTs for FDG-avidity. Of 557 resected nodules in 541 patients, 39 nodules in 38 patients were benign (15 females, 23 male) for a benign resection rate of 7% (39/557). There was no significant difference between benign and malignant groups across sex, race, nodule size or attenuation. Patients with benign nodules were younger (mean age 59 vs. 65 years in the malignant group; p=0.005). 75% of patients with benign nodules were smokers versus 80% in the malignant group (p=0.04). In the benign nodule group, 14 patients (36%) had a cancer history. Benign pathology results were: 15 granuloma, 6 chronic inflammation, 5 hamartoma, 5 abscesses, 2 inflammatory pseudotumor, 2 organizing pneumonia and 1 case each of bronchogenic cyst, fibrous tumor, lipoid pneumonia and lymphoepithelioma. 62% of were in the right lung, and 46% were in an upper lobe. Nodule size was 10-95 mm (mean 29). CT nodule morphology was round/ovoid in 16, and triangular/angular in 3. Nodule border was lobulated in 4, smooth in 7 and spiculated in 8. Cavitation was present in 4 nodules, 14 were exclusively soft tissue attenuation and one contained fat. By attenuation, 18 were solid, and 1 was non solid (ground glass). Of the 18/38 (47%) patients who underwent preoperative PET/CT scan, nodule FDG uptake was: 5 intense, 10 mild, 3 none. Our benign resection rate for lung nodules is 7%. While in many cases the imaging characteristics of surgically proven benign lung nodules and their clinical management are appropriate, following clinical guidelines for nodule management may further reduce the benign resection rate. The use of PET/CT and follow up low dose chest CT for PET/CT negative or mild uptake lesions to confirm nodule stability over time is a pathway for management that requires reinforcement.