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

Purpose: 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. Materials and methods: Data deriving from 579 evaluable patients entered two randomized trials on radiotherapy (RT) for MSCC were revised. Results: 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 x 3 Gy and remaining four patients 2 x 8, 5 x 4, or a single dose of 7 and 4 Gy, respectively. The median cumulative Biologically Effective Dose (BED) calculated was 114.5 Gy2 (range, 80-120 Gy2). 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. Conclusions: 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 Gy2.