Impact of positron emission tomography (PET) in stage III non-small cell lung cancer (NSCLC): A prospective randomized trial (PET START)

7548 Background: Patients with stage III NSCLC are potentially curable using combined modality therapy (CMT) with chemotherapy and radical radiation (RT). The use of PET-CT rather than conventional imaging (CI) may better identify patients for CMT by enhanced tumor staging and improved definition of RT treatment volumes. Methods: Patients with stage III NSCLC (based on histology/cytology, brain CT/MRI, CT thorax, CT/US abdomen, and bone scan) who were considered candidates for CMT were randomized to either PET-CT or CT for RT treatment planning. The primary outcome was the proportion of patients who did not receive CMT because their tumor was upstaged to Stage 4 or their intrathoracic tumor was too extensive for radical RT. Overall survival (OS) and alteration of RT treatment planning volume were secondary outcomes. Target sample size was 400 patients based on a hazard rate reduction of 30% in OS at 2 years in favor of PET-CT with 2-sided alpha = 0.05 and 80% power. We also postulated that 200 patients would be required to detect a 20% difference between arms for the primary endpoint. 5 centers in Ontario participated. Results: The trial commenced in August 2004. In November 2008 after a planned interim analysis for the primary outcome, the Data Safety Monitoring Board recommended stopping recruitment because of superior efficacy with PET-CT. 304 patients were randomized and 289 had analyzable data. 25 patients were unsuitable for CMT: 21 in the PET-CT arm (16 upstaged to Stage 4 and 5 unsuitable for radical RT) and 4 in the CT arm (unsuitable for radical RT). Thus, 21 of 140 (15%) patients in the PET-CT arm achieved the primary outcome compared with 4 of 149 (2.7%) in the CT arm, P= 0.0002. Conclusions: This is the first randomized trial in stage III NSCLC showing that PET-CT is superior to CT planning alone in selecting appropriate patients for CMT. Longer patient follow-up will determine potential impact on OS. No significant financial relationships to disclose.