Longitudinal Study of Local Ablative Therapy in Oligometastatic Disease

Inclusion Criteria: * Histology or cytology proven non-haematological cancer * Stage IV disease * ECOG performance status ≤ 2 * Life expectancy \> 6 months * A baseline scan within 42 days of inclusion (PET-CT or CT or MRI scan) is required, preferably within 28 days for optimal prospective evaluation * Primary tumor must be controlled, defined by the radiographical response of the primary tumor by systemic or local treatment. If progressing, it is planned to be treated with local ablative therapy (LAT) * Oligometastatic disease according to the ESTRO-EORTC classification, both de-novo and induced, including oligoprogression * A maximum of five oligometastases or oligopersistent/oligoprogressive lesions. More than five metastases are allowed in the following cases, 1) location in a defined anatomical entity or 2) location in immediate proximity and as such, cannot be treated separately * All oligometastatic lesions must be planned for definitive LAT. If all visible/progressive/persistent disease is not treated, the patient cannot be included * Local ablative therapy must be deemed clinically relevant for the individual patient by the treating team of physicians, or a multidisciplinary team and discussion must be documented in the patient chart * Ability to understand and the willingness to sign a written informed consent document Exclusion Criteria: * Pregnancy * Diffuse cancer disease, which cannot be locally ablated, i.e., leptomeningeal carcinomatosis, malignant pleural effusions, lymphangitic carcinomatosis, or peritoneal carcinomatosis * If LAT is deemed unsafe by the MDT (e.g., tumor perforation of hollow organs) In addition, the patients receiving SBRT to oligometastatic sites should comply with the following criteria. * The size of the target is limited by the ability to safely deliver locally ablative doses to the metastatic lesions. Generally, an upper limit of 5 cm is recommended * If the patient has received previous radiotherapy, the combined dose at the radiation site must not exceed the dose constraints according to Appendix 2 - Radiotherapy Recommendations