The reported hypo- and hyperfractionation studies have a 'trial-and-error' approach for dose-level estimation in common. In a recent in silico trial in 26 stage III NSCLC patients, we have investigated the use of a dedicated software tool for individual dose escalation by hypofractionation. Based on an existing, clinical IMRT/VMAT treatment plan (66 Gy in 33 fractions), radiation dose was escalated by scaling the radiation dose until the maximum tolerated dose constraints for the healthy lung, the esophagus, spinal cord, brachial plexus or heart was met. The aim of this present study is to test the feasibility and toxicity of individualized hypofractionated radiotherapy, and to report outcome data. In case this phase II trial has favorable results, a phase II/III trial on maximally tolerable, individualized, hypofractionated radiotherapy within a shorter overall-treatment time is aimed for.