Stereotactic Body Radiotherapy in Patients With Rare Oligometastatic Cancers (OligoRARE)

Inclusion Criteria: * Histologically confirmed malignancy with metastatic disease detected on imaging. Biopsy of metastasis is preferred, but not required. * Controlled primary tumour, defined as: * at least 3 months since original tumour treated definitively, with no progression at primary site * Total number of oligometastases of 1-5 including: * Brain metastases amenable to radiosurgery or fractionated stereotactic radiotherapy patient who had neurosurgical resection before trial inclusion are allowed and resected brain metastases count to the total number of oligometastases * All sites of disease can be safely treated based on the judgement of an experienced radiation oncologist * ECOG score 0-2 * Life expectancy \> 6 months * Age 18 or older * Before patient randomization, written informed consent must be given according to ICH/GCP, and national/local regulations. Exclusion Criteria: * Primary cancer of prostate, breast, lung or colorectal * Serious medical comorbidities precluding radiotherapy: * These include interstitial lung disease in patients requiring thoracic radiation, Crohn's disease in patients where the GI tract will receive radiotherapy, or ulcerative colitis where the bowel will receive radiotherapy and connective tissue disorders such as lupus or scleroderma. * For patients with liver metastases, moderate/severe liver dysfunction (Child Pugh B or C) * Substantial overlap with a previously treated radiation volume. Prior radiotherapy in general is allowe…