Reirradiation of metastatic spinal cord compression: definitive results of two randomized trials

Incidence, outcome and prognostic factors of metastatic spinal cord compression (MSCC) patients reirradiated for in-field recurrence were analyzed. Radiation therapists' attitude in reirradiate spinal cord relapses, doses adopted and incidence of myelopathy were also examined.

Data deriving from 579 evaluable patients entered two randomized trials on radiotherapy (RT) for MSCC were revised.

Twenty-four (4.15%) patients had an in-field recurrence and 12 (50%) were reirradiated. At the time of analysis all reirradiated patients had died. Median time from first and second RT was 5 months (range, 2-31). Six patients received an 8 Gy single-dose, 2 patients 5×3Gy and remaining four patients 2×8, 5×4, or a single dose of 7 and 4 Gy, respectively. The median cumulative Biologically Effective Dose (BED) calculated was 114.5 Gy(2) (range, 80-120 Gy(2)). Six of seven (85.7%) ambulant patients maintained walking ability, whereas none of five not ambulant patients recovered the function. Median duration of response was 4.5 months (range, 1-24). The effect of reirradiation on motor function was significantly associated with walking capacity before reirradiation. Myelopathy was never recorded.

In MSCC reirradiation was safe and effective. Patient walking capacity before reirradiation was the strongest prognostic factor for functional outcome. Reirradiation was given in about one-half of patients with in-field recurrence and different doses and fractionations were used, even though cumulative BED was in all cases ≤120 Gy(2).