Immunotherapy or Targeted Therapy With or Without Stereotactic Radiosurgery for Patients With Brain Metastases From Melanoma or Non-small Cell Lung Cancer

Most important inclusion criteria: * Newly diagnosed, previously untreated (except for surgery, see below) asymptomatic or oligo-symptomatic brain metastases, e.g., controlled symptomatic seizure disorder. Note: patients with neurological symptoms or signs that require more than a stable dose of 4 mg dexamethasone equivalent for more than one week are not considered oligo-symptomatic. * Requirements for brain metastases: * Brain metastases must be previously untreated, except for surgery. * Prior surgery (including biopsies, resection, and cyst aspiration) for brain metastases is allowed. Residual and measurable disease after surgery is not required, but surgery must have confirmed the diagnosis. An MRI performed within 72 hours post-surgery should be available. * Number and size of metastases at diagnosis of brain metastases: * Maximum 1-10 brain metastases at screening * At least one brain metastasis must be of ≥5 mm in diameter * In case of 1-4 brain metastases: * Longest diameter of largest brain metastasis must be ≤30 mm * In case of 5-10 brain metastases: * Largest metastasis must be ≤10 mL in volume and longest diameter must be ≤30 mm * Maximum cumulative brain metastases volume must be ≤30 mL * Primary disease of histologically confirmed (from primary tumour or from a metastatic lesion, including in the brain) melanoma or NSCLC * Requirements for patients with melanoma: * Prior treatment, including treatment with immune-checkpoint inhibitors is permitt…