 Lung cancer is a problem of the elderly: 30 of the lung cancer patients are aged 75 years. Due to underrepresentation of elderly patients in clinical trials there is a lack of evidence to select the optimal treatment strategy for these patients. Concurrent radiochemotherapy RCHT has been recognised as the standard treatment of stage III NSCLC patients with a good performance status. Evidence for this treatment was gained in clinical trials that mostly excluded elderly patients. Furthermore, the survival gain obtained with combined RCHT, comes with a significant increase in toxicity. Therefore, information on benefits and harms of intensified treatment with concurrent RCHT among a subpopulation of medically fit elderly patients is still lacking. Moreover, reliable tools are needed to distinguish the subgroup of fit patients from frail patients, i.e. those expected to experience important toxicity. 