A Multicenter Phase II Study of Stereotactic Radiotherapy for Centrally Located Lung Tumors (STRICT-LUNG STUDY) and Ultra-centrally Located Lung Tumors (STAR-LUNG STUDY).

Inclusion Criteria: * Histology or cytology proven non-hematological cancer or known cancer with local progressive recurrence. * ECOG performance status ≤ 2. * Age \> 18 years old. • Life expectancy \> 6 months. * Maximum one central tumor with the diameter ≤ 5 cm or \> 1 adjacent located tumors with a summarized diameter (measured from the outer margin from one tumor to the outer margin of the other) of maximum 5 cm on a diagnostic CT-scan. * Medically inoperable or refused surgery. * The central tumors must be localized within or touching the 2.5 cm-zone of the PBT, or within 0.5 cm from the spinal cord, esophagus or heart. Evaluation is primarily performed on the diagnostic CT scan * All metastatic sites are treated or planned for ablative therapy (including surgery). For oligo-progressive disease (OPD), only the sites in progression are required to fulfil this criterion * Adequate lung function to tolerate treatment, at the discretion of the treating physician. • Ability to understand and willingness to sign a written informed consent document. • Patient must be accessible to treatment and follow-up procedures * Fertile women must have a negative pregnancy test. Fertile men and women must use effective contraception. Fertile women included in the study must use effective contraception for the duration of study treatment and one month thereafter. * Ultra-centrally located tumors are tumors located within the 0.0 to 0.5 cm zone of the trachea, main bronchi or intermediate bronchus. Evaluation is primarily performed on the diagnostic CT scan * Patients with other non-central tumors synchronous with the central lesion may be included and treated with SBRT in respect to local practice. * A baseline PET/CT scan within 2 months of inclusion. * An ablative strategy should be deemed clinically relevant and it is at the discretion of the treating physician to decide. Exclusion Criteria: * Tumor with intra-bronchial or intra-tracheal growth, as assessed on a diagnostic CT/MR-scan or endoscopic procedure * If the patient has received previous radiotherapy, the combined dose at the radiation site must be evaluated by the treating physician and preferably not exceed the dose constraints * Patient cannot tolerate the physical set up required for SBRT. • Uncontrolled intercurrent illness * Pregnancy * Patient participating in another interventional study * For patients in STAR-LUNG, lack of MR compatibility due to pacemaker, inserted steel or similar.