After induction chemotherapy, all patients received dose‐differentiated accelerated radiotherapy with intensity modulated radiotherapy (IMRT‐DART). The details of this treatment approach were described elsewhere.6 In brief, the cornerstones of this regimen are the sequential chemoradiation mode, the dose increments from 73.8 to 90 Gy depending on tumor size and twice daily treatment with 1.8 Gy per fraction. In the current study, however, the former conventional 3D‐target splitting technique was replaced by IMRT. As of 2017, ultracentrally located tumors with invasion of the central vessels or airways in pretreatment contrast enhanced thoracic CT scan were treated ‐ regardless of size ‐ with a total dose of 61.2 or 73.8 Gy in order to reduce the risk of lethal hemorrhage due to rapid tumor regression.24 Involved lymph nodes received 54–61.2 Gy in twice daily fractions of 1.8 Gy each. The nodes next to the involved area were treated with 1.4 Gy bid to a total dose of 47.6 Gy. As for dose constraints, the following limits were applied24, 25, 26, 27, 28: mean lung dose (MLD) < 20 Gy, V25total lung < 30%, V20ipsilateral lung < 50%, mean esophageal dose (MED) < 34 Gy, maximum dose to the spinal cord 45 Gy (maximum dose of 1.3 Gy per fraction), V25heart < 10%. In order to mitigate potential esophageal toxicity, all patients received local antimycotic prophylaxis.29 Radiotherapy planning was performed when patients received the second cycle of systemic treatment. Induction chemotherapy consisted of two cycles of either Cisplatinum or Carboplatinum combined with Pemetrexed, Gemcitabine or Vinorelbine according to histology. As of September 2017, patients received Durvalumab maintenance therapy for one year after the end of radiotherapy.5, 30