OBJECTIVE: @entity1566 is arguably the most feared complication in radiotherapy and has historically limited the @entity146 of @entity5 treatment. We report a case series of 6 @entity1 treated with radiosurgery who developed delayed @entity602 . METHODS: Between 1996 and 2005, 1075 @entity1 with benign or malignant @entity5 were treated by CyberKnife (Accuray, Inc., Sunnyvale, CA) robotic radiosurgery at Stanford University Medical Center and the University of Pittsburgh Medical Center. @entity1 were followed prospectively with clinical and radiographic assessments at 1- to 6-month intervals. A retrospective review identified @entity1 who developed delayed @entity15698 . Six @entity1 (5 @entity1 , 1 @entity1 ) with a mean age of 48 years (range, 25-61 years) developed delayed @entity602 at a mean of 6.3 months (range, 2-9 months) after spinal radiosurgery. Three @entity5 were metastatic; 3 were benign. The metastases were in the upper to midthoracic spine, whereas the @entity5 were partially in the cervical region. Three cases involved previous radiation therapy. RESULTS: Dose volume histograms were generated for target and critical structures. Clinical and dosimetric factors were analyzed for factors predictive of @entity1566 . Specific dosimetric factors contributing to this complication could not be identified, but one-half of the @entity1 with @entity602 received spinal cord biological equivalent doses exceeding 8 Gy. CONCLUSION: Delayed @entity602 after radiosurgery is uncommon with the dose schedules used in this case series. @entity1161 to the spinal cord occurred over a spectrum of dose parameters that prevented identification of specific dosimetric factors contributing to this complication. Primarily, biological equivalent dose estimates were not usable for defining spinal cord tolerance to hypofractionated dose schedules. We recommend limiting the volume of spinal cord treated above an 8-Gy equivalent dose, because half of the complications occurred beyond this level.

Delayed XXXX after spinal radiosurgery.

@entity1 :: ('9606', 'Species') :: ['women', 'Patients', 'patients', 'man'] @entity146 :: ('MESH:D001523', 'Disease') :: ['aggressiveness'] @entity5 :: ('MESH:D009369', 'Disease') :: ['benign tumors', 'spinal tumor', 'spinal tumors', 'tumors'] @entity15698 :: ('MESH:D009381', 'Disease') :: ['radiation-induced myelopathy'] @entity1161 :: ('MESH:D011832', 'Disease') :: ['Radiation injury'] @entity602 :: ('MESH:D013118', 'Disease') :: ['myelopathy'] @entity1566 :: ('MESH:D013119', 'Disease') :: ['Spinal cord injury', 'spinal cord injury']
@entity15698 :: (MESH:D009381,Disease) :: ['radiation-induced myelopathy']
