Inclusion Criteria:  Age ≥ 18 years Histologically confirmed or high probability of non-small cell lung cancer, or metastasis from other cancer, located ≤ 1 cm from the thoracic wall. High probability refers to consensus on the diagnosis at the local multi-disciplinary lung tumor conference. Eligible for stereotactic body radiation therapy in ablative doses (i.e. 66/45 Gy in 3 fractions) following national guidelines (2). Can read and understand Danish. Written and orally informed consent. Performance status 0-2 Life expectancy > 6 months assessed by the physician during the consultation.  Exclusion Criteria:  Previous radiation therapy in the thoracic region (lung, breast or mediastinum), if it is not possible to produce a new radiation plan of 66 or 45 Gy in 3 fractions that considers previous radiation therapy and still complies with all constraints, including dose to the thoracic wall. Previous surgery in the thorax is allowed. Mental or social conditions preventing full understanding of the information or the planned treatment and follow-up.