Background: The purpose of the current study was to retrospectively investigate clinical outcome and potential prognostic factors after reirradiation (Re-RT) for in-field recurrence of metastatic spinal cord compression (MSCC).
Methods: Re-RT with 1 x 8 Gy (n = 48), 5 x 3 Gy (n = 29), 5 x 4 Gy (n = 30), 7 x 3 Gy (n = 3), 10-12 x 2 Gy (n = 11), or 17 x 1.8 Gy (n = 3) was administered to 124 patients. Cumulative biologically effective dose (BED) (first course of RT plus re-RT) ranged from 77.5 Gy(2) to 142.6 Gy(2), and was <or=120 Gy(2) in 114 (92%) patients. Twelve potential prognostic factors were investigated for associations with motor function and survival.
Results: Motor function improved in 45 (36%) patients, was stable in another 62 (50%) patients, and deteriorated in 17 (14%) patients. Upon multivariate analyses, the effect of Re-RT on motor function was significantly associated with the effect of the first course of RT (P = .048), Eastern Cooperative Oncology Group (ECOG) performance status (P = .020), time to development of motor deficits before Re-RT (P = .002), and visceral metastases (P < .001). Survival was associated with ECOG performance status (P < .001), ambulatory status before Re-RT (P < .001), time to development of motor deficits (P = .018), and visceral metastases (P <.001). Re-RT dose schedule or cumulative BED had no significant impact on functional outcome or survival. Acute toxicity was mild, and late toxicity, such as radiation myelopathy, was not observed.
Conclusions: Given the limitations of a retrospective study and the relatively short follow up after Re-RT, spinal reirradiation appeared to be effective and safe when the cumulative BED is </=120 Gy(2). Motor function after Re-RT was associated with the effect of first irradiation, performance status, time to development of motor deficits, and visceral metastases, whereas the Re-RT schedule had no significant impact.
(c) 2008 American Cancer Society.