核素對轉移性骨痛的治療

Radionuclide SR-89 Therapy for Metastatic Bone Pain

癌患者的治療中，轉移性骨痛的處理是相當重要的。早期的骨痛可藉傳統式治療法加以控制；這些治療包括：化學治療法、體外放射線照射法、止痛劑與激素（荷爾蒙）療法。對於晚期轉移性骨痛，傳統式療法多半無效。1941年開始，P-32核素療法被引進使用，可惜會導致骨髓抑制作用。近來，鍶－89（Strontium-89, Sr-89）被引用於轉移性骨痛之治療；大約80-85%的患者可得到治療良效。通常骨痛在治療後2至4週消失，而持續約3至6個月，由於Sr-89核種注射後，集中於轉移癌的約10倍於正常骨髓，即使發生白血球、血小板的輕度降低，其副作用仍相當輕微；通常在注射後約4至5週，會有20%的降低，但在10至12週時恢復到原來的數值。由於副作用的輕微，Sr-89療法可與體外照射或化學療法併用，以提高療效。為了加強Sr-89療法的效益，往往可以併用放射性促進劑（radiosensitisers），例如：氫氧化尿素（hydroxyurea）。此種併用療法，目前正在臨床的大型研究評估中。總括而言，Sr-89療法對於轉移性骨痛的減輕或消除，大有助益；更能改善患者的生活品質。它實在是轉移性骨痛患者的一大福音。

Metastatic bone pain is an important problem in managing patients with cancer. Conventional therapeutic methods are usually effective in controlling bone pain in the early stage of disease. These include chemotherapy, external radiation, analgesics and hormonal control. In a significant number of patients these measures fail later in the course of disease. Radionuclide therapy with P-32 sodium phosphate was first used to treat bone metastases in 1941. However, the side effect of bone marrow suppression was frequently noted. Recently, Strontium-89 (Sr-89) became available for treatment of metastatic bone pain. About 80%-85% of patients get a good response. Pain relief starts in 2-4 weeks and lasts 3-6 months.The side effects are mild decreased of white blood counts and platelets because the ratio of tumor to the normal bone is 4-12 times. About 20% decreased of original values is noted at 4-5 weeks post-therapy. White blood counts and platelets will recover to original values at 10-12 weeks post-therapy. Because of mild side effects, Sr-89 therapy can be combined with external radiotherapy and chemotherapy to get better results.To enhance the effects of Sr-89 therapy, radio-senstizer such as adriamycin, carboplatin, and hydrea were given. The preliminary results are encouraging to show better results. Further large scale studies are needed to confirm these effects.In conclusion, Sr-89 is very helpful in reducing the metastatic bone pain and improving the quality of life. it is the ideal therapy for patients with metastatic bone pain.