Strontium-89 (Metastron) and the bisphosphonate olpadronate reduce the incidence of spinal cord compression in patients with hormone-refractory prostate cancer metastatic to the skeleton

Spinal cord compression (SCC) is a devastating complication of metastatic cancer. We investigated the potential beneficial effect of two palliative therapies - strontium-89 (Metastron) and the nitrogen-containing bisphosphonate olpadronate - on the incidence of SCC in hormone-refractory prostate cancer (HRPC) metastatic to the skeleton. We retrospectively studied 415 patients with histologically proven prostate cancer who underwent bone scintigraphy at the time of diagnosis and were followed up at the Leiden University Medical Center between 1990 and 1999. Medical or surgical castration was undertaken in 172 patients with evidence for skeletal metastases. Within 2 years, 147 of these patients (85%) developed HRPC associated with severe progressive bone pain. Palliative treatment was given to 131 patients in the form of local radiotherapy (n=10), Sr-89 (n=46) or intravenous olpadronate (n=66), with (n=57) or without (n=9) maintenance oral olpadronate. Nine patients received both 89Sr and olpadronate at various intervals. Sixteen patients who did not receive any of these treatments were used as historical controls. There was no significant difference in baseline characteristics between treatment modalities. The incidence of SCC was 17% in the whole group, and highest in controls receiving no palliation (50%). None of the patients treated with local radiotherapy, only 4% of patients receiving Sr-89 and 21% of patients given olpadronate developed this complication. Our findings suggest a significant reduction in SCC in patients with symptomatic HRPC metastatic to the skeleton who receive palliative therapies. Local radiotherapy completely prevents the incidence of SCC, Sr-89 leads to an important decrease in this complication and olpadronate induces a significant. albeit smaller decrease in the incidence of SCC. The use of these agents opens new avenues in the difficult management of patients with advanced prostate cancer who are most at risk of developing SCC.