PRIME_LUNG: Primary Radiotherapy In MEtastatic Lung Cancer - A Pilot Study

Inclusion Criteria: * Have provided written informed consent for the trial. * Be ≥ 18 years of age on day of signing informed consent. * Newly diagnosed, metastatic (stage IV), non-small cell lung cancer (NSCLC), not amenable to curative surgery or curative radiotherapy * Histological or cytologically documented NSCLC * EGFR/ALK/ROS1 Wild-type * Primary disease suitable for radiotherapy and not requiring immediate palliative irradiation * ECOG 0-1 Exclusion Criteria: * Medically unfit for systemic therapy * EGFR/ALK/ROS1 mutation positive * Has had previous thoracic radiotherapy of \> 36Gy in 12 fractions (or equivalent) within the 6 months prior to randomisation. * Has diagnosed and/or treated additional malignancy within 3 years prior to randomisation with the exception of: curatively treated basal cell carcinoma of the skin, squamous cell carcinoma of the skin, curatively treated early-stage cervical cancer, breast cancer or prostate cancer with no evidence of active disease. Other exceptions may be considered following consultation with the principal investigator. * Has a history of (non-infectious) pneumonitis or current pneumonitis that requires active corticosteroids with a dose equivalent of prednisolone\>10mg/d. * Has had any systemic anti-cancer therapy within 4 weeks prior to randomisation * A known diagnosis of idiopathic pulmonary fibrosis * Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial. * Uncontrolled brain metastases defined as not amenable to surgery or stereotactic radiotherapy