[Encounter of cancer cells with bone. Radiotherapy for bone metastasis of cancer].

Almost all bone metastases of cancer with pain are indicated to radiotherapy (RT) . Pathological fracture, impending fracture at lower extremities and radio-resistant tumor should receive preceding surgery. RT is set up to fix lesional bone and consists of 30Gy÷10fr÷2w to rectangular fields opposed anteroposteriorly in general. RT-field includes gross tumor volume plus clinically extent of tumor added set-up error. Pain relief is obtained around 80 to 90%. Re-irradiation may be also effective even with small dose. RT is feasible, minimally invasive, and effective for palliative or symptomatic treatment. RT has, however, adverse effects, for example, radio-induced dermatitis and bone marrow suppression. Pay attention for large field or high dose. Optimum field and dose fraction schedule should be considered.