Retreatment of the spinal cord with palliative radiotherapy

We conducted this retrospective review of patients whose spinal cord was irradiated twice to evaluate the outcome in terms of palliation and long-term side effects.

Eight patients (4 females, 4 males; median age: 67 years) were identified whose spinal cord had been irradiated twice between July 1990 and July 1997, usually for the management of bone metastases. All patients were followed up until their death from progressive disease. The Karnofsky performance score at the time of retreatment ranged from 20% to 90%. Total dose for the first treatment ranged from 29 to 50 Gy (median: 38 Gy) with single doses 1.25-3 Gy; the total dose for the retreatment ranged from 29 to 38 Gy (median: 30 Gy) with a single dose 1.8-4 Gy. The cumulative dose ranged from 59 to 88 Gy (median: 67.5 Gy). The overlap in the site of retreatment consisted of 1-3 segments, whereas in one patient, 2 single segments were treated twice. The outcome in terms of progressive disease, the palliative effects, and the development of myelopathy was assessed retrospectively.

The median interval to reirradiation was 30 months (range: 6-63 months), and the median follow-up after the last treatment was 16 months (range: 5-44 months). After reirradiation, 4/7 patients experienced complete pain relief, 2/7 patients experienced minor pain relief, and only 1 patient showed no change. Two patients with paraparesis experienced complete recovery. All patients tolerated retreatment very well. No serious acute side effects requiring any therapy were seen. During follow-up, no patient showed treatment-induced neurologic abnormalities affecting motor and sensory function, and all patients were able to walk and were continent for stool and urine.

On the basis of the findings in this limited number of patients, it is not possible to give clear and general recommendations concerning the optimal total dose and fraction size that will have maximal palliative effects and minimal side effects. However, for the purpose of palliation, retreatment within the dose range used at our institution should be considered, taking the patient's expected life span and clinical symptoms into account.