Is SBRT an appropriate treatment for recurrent and unresectable spinal ependymoma?

We have reirradiated a handful of patients who had 45-54Gy to the spinal cord 5-12 years ago with another course of RT 50Gy/25 to the cord without any neurologic sequelae--this is unpublished (we are working on it). We have also reirradiated small recurrences after a full course of RT to the spinal cord 5-12 years previous, with 800cGyx3 with radiosurgical margins with very good results. We would consider 800x3 with very tight margins for SBRT if the lesion were within 2cm in the setting of 45Gy...

Data in the literature based on Anca Grosu's work on re-irradiaiton of spinal cord show that the cumulative dose to the spinal cord can go up to a nominal BED (alpha-beta ratio of 2 and 2 Gy per fx equivalent) of 60-68 Gy without a significant risk of radiaiton myelopathy. All those patients were treated with conventional techniques and the 2 courses had at least 6 months apart. Sahgal from Sunnybrook analyzed individual patient data (spinal re-RT with SBRT) and determined that the spinal cord p...

If the recurrent tumor is intramedullary (as opposed to extramedullary), more portions of the spinal cord will be reirradiated.