[Radiation therapy for bone metastasis from renal cell carcinoma with emphasis on local control]

If bone metastasis of renal cell carcinoma is neglected, pain, paralysis, and pathologic fracture develope; consequently, the patient's quality of life is significantly lowered. We investigated the local effect of the radiation therapy to the patients with metastasis. The investigation targeted 22 cases (27 parts) of renal cell carcinoma with bone metastasis that were treated with radiation therapy in our hospital during the last 6 years. We analyzed cell type, presence or absence of organ metastasis, irradiated site, therapeutic dose, treatment period, and combination therapy. The object was classified into 2 groups by metastatic site: the group with metastasis in the vertebra, and the group of metastasis in the pelvis or long bones. We examined re-calcification rate, length of time to recalcification emergence, pain relief and duration of effect as therapeutic effects. The irradiated site was vertebra in 14, pelvis in 7, and long bone in 6 patients. The therapeutic dose was 15 to 50 Gy, and the average was 35.7 Gy. No difference was found in the re-calcification rate and length of time to recalcification according to the metastatic site. The pain relief effect was significant in the pelvis and long bone group compared to the vertebra group. The effect lasted longer when the radiation dose was 35 Gy or more, compared with a lower dose. The radiation therapy for renal cell carcinoma with bone metastasis was effective to relieve pain and improve the patients' quality of life. The results showed that early detection and recognition of bone metastasis provide local control.