2017_SBRT_Course Book

Safety of spine SBRT: myelopathy

OAR definition

Dose in patients with radiation myelopathy Conclusion

Study # events

Ryu 2006

SC 6mm CC of TV

1 / 177

9.6Gy to 10%

10% < 10Gy

Gibbs 2009

6 / 1075

NS

D max

8.5 – 26.2Gy

1cm 3 < 8Gy

D max below thresholds using LQ model

Sahgal 2010

5 / 24 case control study

Thecal sack

D max

median 59Gy (nBED 2/2 )

• (Very) Few patients developed radiation induced myelopathy • Dose – response inconclusive • However: follow-up short in majority of patients

ESTRO SBRT 2017 - Matthias Guckenberger

07.09.17

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Safety of spine SBRT: myelopathy Multi-institutional analysis: • 9 cases with radiation induced myelopathy • 66 cases w/o radiation induced myelopathy Sahgal IJROBP 2012 1 fraction 3 fractions 5 fractions 1%probability 9.2 14.8 18.2 2%probability 10.7 17.4 21.5 3%probability 11.5 18.8 23.1 4%probability 12 19.6 24.4 5%probability 12.4 20.3 25.3 • Doses converted to 2Gy equivalent dose (EQD2/2) • Dmax to thecal sack • LARGE confidence intervals

ESTRO SBRT 2017 - Matthias Guckenberger

07.09.17

16

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