Experimental: Low dose Radiation Therapy

In the test group, patients receive radiotherapy with six fractions of 0.5 Gy each over a period of 3 weeks, with 2 doses applied per week (total dose 3.0 Gy). After the 1st follow-up (3 months after radiotherapy), patients receive the patients in both arms have the option to receive a 2nd series of radiotherapy in consultation with the study physician if no improvement in symptoms has occurred or patients are still not sufficiently satisfied with the outcome (this decision is still made by the physician and patient in a blinded manner). The patients from the test group receive another irradiation series with six fractions of 0.5 Gy each according to the same schedule as before (total dose 3.0 Gy and in sum with the first series 6.0 Gy).

Placebo_comparator: Mock Radiation Therapy

In the control group, patients receive sham irradiation with six fractions of 0.0 Gy each over a period of 3 weeks, with 2 treatments per week. After the 1st follow-up (3 months after radiotherapy), patients receive the patients in both arms have the option to receive a 2nd series of radiotherapy in consultation with the study physician if no improvement in symptoms has occurred or patients are still not sufficiently satisfied with the outcome (this decision is still made by the physician and patient in a blinded manner). The patients in the control group, on the other hand, now also receive a radiotherapy with six fractions of 1.0 Gy each over a period of 3 weeks with 2 fractions per week (total dose 6.0 Gy).