An initial experience with FDG-PET in the imaging of residual disease after induction therapy for lung cancer

Background. The 2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) imaging is an advance over computed tomography alone in the staging of untreated nonsmall cell lung cancer (NSCLC). Aside from one 9-patient study, there are no data comparing FDG-PET imaging with surgical staging of NSCLC after induction therapy. Methods. We reviewed our institutional experience with FDG-PET imaging followed by surgical staging of nonsmall cell lung cancer after induction therapy. A nuclear physician blinded to surgical findings reviewed the FDG-PET scans and assigned a clinical TNM stage. A thoracic surgeon assigned a pathologic TNM stage. Then the clinical TNM stage and the pathologic TNM stage were compared. Results. Fifty-six patients (30 males and 26 females; median, age 60) with nonsmall cell lung cancer underwent chemotherapy (40 patients), chemoradiation (11 patients), or radiation alone (5 patients) followed by PET and operations. PET had a positive predictive value of 98% for detecting residual viable disease in the primary tumor. PET over-staged nodal status in 33% of patients, under staged nodal status in 15%, and was correct in 52%. PET correctly classified all patients with M1 disease. Conclusions. Positron emission tomography after induction therapy accurately detects residual viable primary tumor, but not the involvement of mediastinal lymph nodes. (C) 2002 by The Society of Thoracic Surgeons.