Short-course radiotherapy is not optimal for spinal cord compression due to myeloma

Purpose: To investigate the suitability of short-course radiotherapy (RT) for spinal cord compression (SCC) in myeloma patients. Methods and Materials: Data for 172 myeloma patients irradiated between January 1994 and December 2004 for SCC were retrospectively evaluated. Short-course RT (1 × 8 Gy, 5 × 4 Gy, n = 61) and long-course RT (10 × 3 Gy, 15 × 2.5 Gy, 20 × 2 Gy, n = 111) were compared for functional outcome up to 24 months after RT. In addition, 10 potential prognostic factors were investigated. Results: Improvement of motor function occurred in 90 patients (52%). Forty-seven percent of nonambulatory patients regained the ability to walk. Functional outcome was significantly influenced by the time of developing motor deficits before RT. Improvement of motor function was more frequent after long-course RT than after short-course RT: 59% vs. 39% (p = 0.10) at 1 month, 67% vs. 43% (p = 0.043) at 6 months, 76% vs. 40% (p = 0.003) at 12 months, 78% vs. 43% (p = 0.07) at 18 months, and 83% v 54% (p = 0.33) at 24 months. A subgroup analysis of the long-course RT group demonstrated a similar functional outcome for 10 × 3 Gy when compared with 15 × 2.5 Gy and 20 × 2 Gy. Conclusions: Long-course RT is preferable for SCC in myeloma patients because it resulted in better functional outcome than short-course RT. Treatment with 10 × 3 Gy can be considered appropriate.