Gamma knife is considered unsuitable for lesions larger than 10cc. In this presentation, the author- Prof Deepak Agrawal- Gamma-Knife expert and an accomplished neurosurgeon shows how this size criteria is a myth
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Gamma Knife for large and giant Lesions
1. Gamma Knife for Giant
intracranial lesions:
An Indian’s perspective
Dr Deepak Agrawal,
Professor, Neurosurgery & Gamma Knife,
All India Institute of Medical Sciences, N Delhi
2. Large
Most authors have defined large VSs as lesions with one dimension > 3
cm, but the tumor volume has not yet been defined.
>10cc is considered large in recent literature
Fractionated Gamma Knife Radiosurgery as Initial Treatment for Large Skull Base Meningioma. Hye Ran Park, Jae Meen Lee, Kwang-Woo Park, Jung
Hoon Kim, Sang Soon Jeong, Jin Wook Kim, Hyun-Tai Chung, Dong Gyu Kim, Sun Ha Paek. Exp Neurobiol. 2018 Jun; 27(3): 245–255.
3. Are ‘large’ Lesions unsuitable for GK
All definitions of ‘large’ are based on Vestibular schwannomas &
classical teaching of medium & large for VS
Extrapolated to other lesions without any scientific merit!
4. Why 3cm & 4cm limits
No actual guidelines in place.
No literature on volume limits for gamma knife
In 1983, Kjellberg et al. constructed a 1% dose volume isoeffect line that
was used as a guideline for radiotherapy dose prescriptions at his center.
Kjellberg RN, Hanamura T, Davis KR, Lyons SL, Adams RI: Bragg-Peak proton-beam therapy for arteriovenous malformations of
the brain. N Engl J Med 1983;309:269–274
5.
6.
7. Brain Metastasis
Initially less than 3 metastasis were only considered
suitable
It is now clear treating even 20 or more brain mets
with GK is better than WBRT!
No 1 indication of GK in USA!!!
Kim CH, Im YS, Nam DH, Park K, Kim JH, Lee JI. Gamma knife radiosurgery for ten
or more brain metastases. J Korean Neurosurg Soc. 2008;44(6):358-63.
Hatiboglu MA, Tuzgen S, Akdur K, Chang EL. Treatment of high numbers of brain
metastases with Gamma Knife radiosurgery: a review. Acta Neurochir (Wien). 2016
Apr;158(4):625-634.
16. AIIMS Data
FU available in 55%
27% static
62% decreased
11 % increased
17. ADVANTAGES OVER EBRT
Can be repeated if required
Decreased incidence
Radiation changes/ edema
Cognitive decline
18. Limitations to dosing in GK
Extremely long treatment times
Proximity to critical structures’:
Optic pathway
Brainstem
19. oxymoron
/ˌɒksɪˈmɔːrɒn/
Noun
a figure of speech in which apparently contradictory terms appear in conjunction
‘Unsuitable for Gamma-Knife’
20. CONCLUSIONS
GAMM KNIFE MAY BE SUITABLE IN SELECTED LARGE/GIANT LESIONS
WITH BETTER OUTCOMES AND DECREASED TOXICITY AS COMPARED
TO CONVENTIONAL RADIOTHERAPY