Hyperthermia Enhanced Re-irradiation of Loco-regional Recurrent Tumors

Inclusion Criteria: * prior radiotherapy of the treatment side with a treatment dose \> 30 Gray (Gy) EQD2 (calculated with alpha/beta value of 9) * local/ regional / or oligometastatic tumor recurrence. Maximum number of three macroscopic tumor lesions with at least one of them receiving prior radiotherapy * macroscopic tumor recurrence * side of recurrence is amenable to hyperthermia (abdomen, pelvis, extremities, spine, cervical lymphnodes) * planned re-irradiation dose of at least 40 Gy EQD2 (calculated with alpha/beta value of 9) Exclusion Criteria: * \>3 macroscopic tumor lesion * brain metastases * recurrence is amenable to local ablative radiotherapy (brachytherapy or stereotactic radiotherapy) * recurrence region is not amenable to hyperthermia (lung, liver, mediastinum) * contraindications for hyperthermia (serious cariovascular disease, ICD or larger implants at the treatment site) * psychiatric disorders that impede proper informed consent * serious comorbidities with very limited prognosis quo ad vitam