A prospective evaluation of two radiotherapy schedules with 10 versus 20 fractions for the treatment of metastatic spinal cord compression: final results of a multicenter study.

Background: The optimal treatment of patients with metastatic spinal cord compression (MSCC) is still being debated. The current observational multicenter study, performed prospectively by the authors, evaluated two radiotherapy (RT) schedules and prognostic factors with respect to functional outcome

Methods: In the current study, 214 patients with MSCC were irradiated between April 2000 and September 2003 with 30 gray (Gy) per 10 fractions per 2 weeks (n = 110) or with 40 Gy per 20 fractions per 4 weeks (n = 104). Motor function and ambulatory status were evaluated before RT and until 6 months after RT. The following potential prognostic factors were investigated: RT schedule, performance status, age, number of irradiated vertebrae, type of primary tumor, pretreatment ambulatory status, and length of time developing motor deficits before RT.

Results: Both groups were balanced for patient characteristics and potential prognostic factors. Motor function improved in 43% of patients after 30 Gy and in 41% of patients after 40 Gy (P = 0.799). Posttreatment ambulatory rates were 60% and 64% (P = 0.708), respectively. A multivariate analysis demonstrated that a slower progression of motor deficits before RT (P < 0.001), a favorable histology of the primary tumor (P < 0.001), and being ambulatory before RT (P = 0.035) were associated with a better functional outcome. RT schedule (P = 0.269) and other variables had no significant impact. Acute toxicity was mild, and late toxicity was not observed during the period of follow-up. Follow-up was 12 (6-28) months in patients surviving >/= 6 months.

Conclusions: Thirty gray per 10 fractions was preferable to 40 Gy per 20 fractions, because it was associated with similar outcome, less treatment time, and lower costs. The type of tumor, pretreatment ambulatory status, and length of time developing motor deficits before RT were relevant prognostic factors and should be considered in future studies.