Vertebral Fractures After Stereotactic Ablative Radiotherapy of Lung Tumors
Todd A. Aguilera MD PhD1, Nicholas Trakul MD PhD2, David B. Shultz MD PhD1, Peter G Maxim PhD1, Maximilian Diehn MD PhD1, and Billy W Loo Jr. MD PhD1
1Department of Radiation Oncology, Stanford Cancer Institute, Stanford CA 2Department of Radiation Oncology, USC, Los Angeles CA; Correspondence [email protected]
Poster #57010
Background• Not much is known about risk of vertebral fracture after stereotactic radiation of
lung tumors
Objective• Evaluate Stanford SABR experience for vertebral fractures that developed in the
coplanar treatment field
Results• Six of 236 patients (2.5%) developed fractures to vertebral bodies that received
considerable dose• Patients were predominantly women and had low bone density
Table of 6 patients and pertinent clinical factors
Sex (Age)
Stg Tx Dose/ fraction #
Max dose (Gy)
Distance to VB (cm)
Prior or multi fx
Rib Fx
Osteo-penia
Time to fx (mo)
1 W(87) 1A CK 30/1 5.5 7.2 prior Y 13
2 W(66) 1A CK 25/1 2.5 10.5 multi Y 24
3 W(64) 1A CK 50/4 48 <1 28
4 M(77) 3B VMAT 25/1 x 2, 20/1
5.5/ 26 <1, 4 multi 12/21
5 W(89) 1B VMAT 50/4 35 <1 Y 9
6 W(81) 1B VMAT 54/3 12.2 6 Y 14
CK= Cyberknife; VMAT= Linac based volume modulated arch therapy; VB= vertebral body
13 mth 25 mth
5 Gy3 Gy 25 Gy10 Gy
5 Gy
Pretreatment 12 months 21 months
This patient had 3 lesions treated and developed fractures at 2 levels.
T8 T10
Vertebral fracture after lung SABR: Summary
• Stereotactic radiation may increase vertebral fracture risk in high risk patients. – Doses as low as 5 Gy may increase risk– One patient had prior fracture– Two patients developed fractures concurrently at untreated levels
• Postmenopausal women with low bone density appear to have the greatest risk.
• At least 2 of 4 patients with clinical follow up had associated pain