3.2.1. Conventional Radiation Therapy

EBRT is widely used as a local treatment for BMs. It can be used to complement surgery or alone in cases with intractable bone pain to reduce the pain and/or prevent pathological fractures, or in cases with spinal cord compression [54]. However, it is likely that conventional EBRT is related to a higher rate of relapse in patients who live longer. Although patients with mechanical instability in skeletal lesions require surgical stabilization, patients with low SINS or Mirels scores typically experience resolution of pain after radiotherapy [55,56]. EBRT generally delivers wide-field radiation in small additive doses, such as 30 Gy in 10 fractions. The dose is delivered to the tumor, although it is limited by the amount that can be tolerated by the surrounding organs at risk, such as the spinal cord.

**Figure 1.** A 39-year-old man diagnosed with multiple lung and spinal metastases of T4 and L4. He underwent metastasectomies for spinal lesions. He also underwent radioactive iodine (RAI) therapy after the spinal metastasectomies and other metastasectomies for BMs, which subsequently appeared in the sacrum, left ilium, and humerus after RAI therapy. Eleven years after the first metastasectomy, he had no local tumor recurrences in the operated lesions; he still performed his normal daily activities and worked without any difficulties. (**a**) Sagittal and (**b**) axial T2-weighted magnetic resonance imaging of the thoracic spine, showing metastasis of T4. (**c**) Spondylectomy of T4 (complete resection of the tumor-affected vertebra) without any significant perioperative complications. (**d**) A recent full-spine radiography showing good maintenance of the reconstructed spine.

> Despite the relative radioresistance of DTC [57], EBRT is the main and standard treatment option for patients with symptomatic or asymptomatic BMs at a higher risk of fracture and/or neurological symptoms.
