Follow up after curative-intent lung cancer treatment

INTERVENTION: Participants who have completed a curative‐intent treatment are randomly allocated to one of two groups. Group 1 (Contrast‐CT): Participants receive a CT scan every six months for two years. This involves being given a a contrast medium through the use of an intravenous catheter (usually placed into a vein of one arm) and images are taken within thirty seconds. Computed tomography multidetector (MDCT) examinations of the chest are performed using either a 64 or a 320 detector‐row CT scanner (Aquilion 64 CT / Aquilion ONE CT; Toshiba Medical Systems, Otawara, Japan). All chest MDCT examinations are obtained with the routine low dose chest MDCT protocol including craniocaudal direction, supine position with both arms raised above the head, single breath hold and a scan volume ranged from the level of the diaphragm to a level just above the thoracic inlet. The injected volume of contrast medium (Iopromide 300, Ultravist 300; Bayer Vital Gmbh, Leverkusen, Germany) is tailored to the individual body weight: <50 kg = 60ml @ 2ml/second vs. >= 50kg = 80ml @ 2.5ml / second with a fixed contrast delay of 35 seconds. Radiation dose exposure is systematically reduced by various methods including automatic exposure control (Toshiba Sure Exposure 3D) and iterative reconstruction algorithms (Toshiba Adaptive Iterative Dose Reduction ADIR 3D). Group 2 (Integrated PET‐CT): Patients receive an integrated PET‐CT scan every six months for two years. This invovles being given radiolabeled glucose (18F‐FDG, a dose regimen of 5 MBq/kg body weight) through an intravenous catheter (usually placed into a vein of one arm). The PET scans start 60 minutes after tracer injection, scanning from the vertex of the scull to the middle of the thigh. A Siemens Biograph MCT 40 PET scanner is used with high resolution reconstruction software (HD PET), also incorporating the time‐of‐flight information in the reconstruction algorithm (TOF PET). Low dose CT scans are performed for attenuation correct CONDITION: Non‐small cell lung cancer ; Cancer ; Non‐Small cell lung cancer PRIMARY OUTCOME: Cancer recurrence or second primary cancer is assessed by further work up of a pathological finding in contrast‐CT or PET‐CT (the particular method of diagnostic work up is board‐defined and does usually consist of either endoscopic or surgical biopsy) respectively and is performed at 6, 12,18 and 24 months. SECONDARY OUTCOME: 1. Other pathological finding are measured through surveillance CT or PET‐CT scans at 6,12,18, and 24 months; 2. Symptomatic recurrences/patient pursuing medical help due to somatic symptoms is measured by methods that are chosen by the treating physician at any time when symptoms occur. Usually, these methods consist of computed tomography or magnet resonance imaging. The decision about the methods chosen in these situations is not part of the current study.; INCLUSION CRITERIA: 1. 18 years of age or older 2. Have a FDG‐PET positive tumor 3. Completed a curative–intent treatment for NSCLC (the PET positivity and the curative character of the cancer therapy are board defined)