This study will test whether reduced-dose radiotherapy is an effective treatment for metastatic tumors with an ATM mutation. The researchers want to find the lowest dose of radiation that would still be effective to treat these tumors.
Histologically confirmed malignancy with at least one metastatic lesion referred for palliative radiotherapy
Pathogenic mutation in ATM (somatic and germline allowed)
ECOG performance status 0-2
Age ≥ 18 years.
Previous radiotherapy to the intended treatment site that precludes developing a treatment plan that respects normal tissue tolerances.
Serious medical co-morbidities precluding radiotherapy.
Pregnant or breast-feeding women.
Lesions excluded from de-escalation include regions in which the risk of local disease progression is unacceptably high, including CNS disease and cord compression, and areas in which re-irradiation would not be feasible, including spinal cord overlap.