Target delineation in GLIOMA

1. PANEL DISCUSSION
TARGET DELINEATION IN GLIOMA
DR KANHU CHARAN PATRO
9/24/2021 1
DR KANHU CHARAN PATRO
MD,DNB(RADIATION ONCOLOGY),MBA,FAROI(USA),PDCR,CEPC
HOD,RADIATION ONCOLOGY
Mahatma Gandhi Cancer Hospital And Research Institute, Visakhapatnam
drkcpatro@gmail.com M-9160470564

2. 9/24/2021 2

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4. Low grade glioma
High grade glioma
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5. GUIDELINES
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6. GUIDELINES
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7. GUIDELINES
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8. 18th AUGUST 2021/BRAIN
G.A. WHITFIELD/ CLINICAL ONCOLOGY /2014
TARGET DELINEATION IN BRAIN TUMOR RADIOTHERAPY IN GLIOMAS
C
C

9. Dr Peethamber
• Imaging protocol
• Any role of nuclear imaging
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11. Some facts
• Diffuse astrocytomas, also referred to as low-grade infiltrative
astrocytomas, are designated as WHO II tumours of the brain.
• Commonly, astrocytomas are confined to white matter although they
can infiltrate and expand the adjacent cortex in later stages.
• However, oligodendroglioma is frequently a cortical-based tumor.
• Although contrast enhancement has been classically associated
with a higher degree of malignancy, contrast enhancement may be
seen in up to 20% of LGG
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12. Oligodendroglioma-cortical location
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14. CT IMAGE
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15. T1

16. T1-
Contrast

17. T2

18. T2 Flair

19. DWI-ADC
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20. SWI

21. Perfusion

22. Dr Sanjay Mishra
• Any typical about high grade Glioma about
imaging finding?
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23. Analysis of images high grade
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24. PET
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25. MRS

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27. Pearls
• Contouring should be performed on a contrast-enhanced,
post-op MRI rigidly registered to a planning CT.
.
• Pre-op imaging should be referenced (or even fused to
planning CT as in this case) to ensure rational target
delineation
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28. Dr Ritesh Bhoot
• Surgical principle
• Any Role of DTI
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29. DTI
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30. OPERATIVE NOTES
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• Solid part
• Cystic part
• Necrosis
• Total taken out or residual

31. Dr V K Reddy
• Imaging protocol
• Prerequisites
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32. PREREQUISITES
• PREOP SCAN
• PER OPERATIVE FINDING
• H/P REPORT
• IHC MARKER/MOLECULAR STUDY
• PLANNING MRI
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33. PRE-OP SCAN
• T1
• T1 CONTRAST
• T2
• T2 FLAIR
• DWI
• ADC MAP
• DIFFUSION
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34. PRE-OP SCAN
• GUIDE
• SOLID PART
• CYSTIC PART
• T2 HYPERINTENSITY AREA
• DISFFUSION RESTRICTION AREA
• HYPER-PERFUSED AREA
• CHOLINE PEAK AREA
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35. PATHOLOGICAL FINDING
• SIZE
• MARKED HYPERCELLULARITY,
• NUCLEAR ATYPIA,
• MICROVASCULAR PROLIFERATION
• NECROSIS
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36. PLANNING SCAN MRI
1. 1MM
2. NO GAP
3. NO TILT
4. NEUTRAL NECK
5. (512x 512) MATRIX
6. FULL FOV
7. VERTEX TO C5
8. CT AND MR SHOULD BE DONE WITH MINIMAL TIME GAP
9. BOTH CT AND MR NEEDS COTRAST SCAN
10. PET IMAGING (MET OR FET), MAY BE USEFUL IN THE
CONTEXT OF RE-IRRADIATION
11. FSPGR/MPRAGE SEQUENCE
12. DICOM CD
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37. Dr Sayan Paul
• Choosing the sequence for contouring
• CTV
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38. T2 FLAIR PREOP
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39. T1 CONTRAST PREOP
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40. T2 FLAIR POST OP
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41. T1 CONTRAST POST OP
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42. FSPGR SEQUENCE
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43. CT POST OP
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44. EXTRAPOLATION OF GTV FROM PREOP MRI
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45. CTV RECOMMENDATIONS
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46. CTV
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47. PTV
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48. Dr P S Bhattachryya
• How to trim the CTV?
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49. TRIM YOURSELF BUT HOW?
• INNER TABLE OF SKULL
• FALX
• CORPUS CALLOSUM
• VENTRICLE
• OPTIC APPARATUS
• BRAIN STEM
• TENTORIUM
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51. TRIM INNER TABLE SKULL IN BONE WINDOW
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52. Trimming along the falx
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If it is confined to one side, CTV[blue]
should be 5mm beyond falx

53. Trimming along the falx- example
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54. The corpus callosum
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55. The corpus callosum
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57. TRIMMING AROUND THE CORPUS CALLOSUM
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• CTV should cross into the contralateral hemisphere if the enhancing or
T2/FLAIR hyperintense tumor encroaches on the corpus callosum (genu
and splenium), anterior commissure, and posterior commissure
• The CTV should cross into the contralateral hemisphere if the enhancing
or T2/FLAIR hyperintense tumor encroaches on the following white matter
tracts: corpus callosum (genu and splenium), anterior commissure (inferior
to the frontal horns and superior the third ventricle), and posterior
commissure (dorsal to the cerebral aqueduct)

58. Trimming around OPTIC apparatus
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1. Where the GTV lies adjacent to the optic chiasm and/or tracts, this may translate
into a wide variation in maximum doses to the optic apparatus as it falls within a
region of high dose gradient falloff.
2. For consistency, a 5 mm extension along the anterior and posterior limbs of the optic
chiasm is recommended, as defined in the ESTRO-ACROP guideline
3. CTV should be limited by, without additional margin, the optic nerves and chiasm but
the optic tracts should not be excluded from the CTV

59. Trimming along the ventricles
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1. The CTV does not need to be excluded from the ventricles, and should be
included in event of ependymal or leptomeningeal involvement
2. If CTV overlapping on ventricle, CTV[blue] should be 5mm beyond ventricular
wall

60. Trimming along the brain stem
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1. The brainstem is an anatomical barrier when the enhancing or T2/FLAIR
hyperintense tumor is not situated along a contiguous white matter pathway;
however, for tumors located in adjacent structures along white matter tracts (i.e.
thalamus, internal capsule), the CTV should extend into the brainstem
2. (whether the ipsilateral half or entire brainstem need to be taken in the CTV
expansion is not well defined)

61. Trimming along the brain stem
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62. Trimming around thalamic area
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The interthalamic adhesion is present in most human brains, and consideration should
be given to extend the CTV into the contralateral thalamus if the enhancing or
T2/FLAIR hyperintense tumor encroaches on the medial thalamus

63. Inter thalamic extension example
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64. High grade glioma
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65. Dr C R Kundu
• Single phase vs two phase treatment
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66. PHASE TREATMENTS
• SINGLE PHASE 60Gy [ EORTC ]
• TWO PAHSE TREATMENT[46Gy+14Gy] [RTOG]
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67. PLAYING WITH TRIPLE ‘E’ CONCEPT
• EXCISIONAL CAVITY
• ENAHANCING COMPONENT
• EDEMA
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68. Comparison
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71. Result
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74. In conclusion
The use of target delineation using
postoperative residual tumor and cavity plus
2-cm margins seems appropriate for patients
with GBM treated with standard RT and
concomitant and adjuvant TMZ.
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75. WHAT SHOULD BE THE GTV?
• Surgical resection cavity plus any residual enhancing tumour
(post contrast T1 weighted MRI scans)
• CAREFUL- Secondary glioblastoma non enhancing areas
may be a component of the tumour
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76. WHAT SHOULD BE THE CTV?
• Based on studies of recurrence pattern and tumour infiltration 20 mm is
the recommended margin applied in all directions of likely tumour
spread along the white matter tracts but reduced at anatomical barriers
• CTV should be modified to include all regions of abnormal T2/FLAIR
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77. Microscopic extension
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78. IHC AND MOLECULAR FINDING
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NS

79. TRIM YOURSELF BUT HOW?
• INNER TABLE OF SKULL
• FALX
• VENTRICLE
• OPTIC APPARATUS
• BRAIN STEM
• TENTORIUM
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80. TRIM INNER TABLE SKULL IN BONE WINDOW
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81. Falx area
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82. Trimming along the falx
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If it is confined to one side, CTV[blue]
should be 5mm beyond falx

83. Ventricular area
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84. Trimming along the ventricles
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1. The CTV does not need to be excluded from the ventricles, and should be
included in event of ependymal or leptomeningeal involvement
2. If CTV overlapping on ventricle, CTV[blue] should be 5mm beyond ventricular
wall

85. Trimming along optic apparatus
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The CTV should be limited by, without additional margin, the optic nerves and
chiasm; however, the optic tracts (+/− chiasm/optic nerves) should not be
excluded from the CTV when the GTV is in contiguity anatomically with the
optic structures

86. Trimming around thalamic area
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The interthalamic adhesion is present in most human brains, and consideration should
be given to extend the CTV into the contralateral thalamus if the enhancing or
T2/FLAIR hyperintense tumor encroaches on the medial thalamus

87. Trimming along the brain stem
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88. Trimming along the brain stem
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1. The brainstem is an anatomical barrier when the enhancing or T2/FLAIR
hyperintense tumor is not situated along a contiguous white matter pathway;
however, for tumors located in adjacent structures along white matter tracts (i.e.
thalamus, internal capsule), the CTV should extend into the brainstem
2. (whether the ipsilateral half or entire brainstem need to be taken in the CTV
expansion is not well defined)

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90. ABTC ?
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93. Conclusion
• The use of limited-margin radiation therapy with concurrent and adjuvant
temozolomide in the treatment of glioblastoma produces patterns of failure
consistent with the existing literature.
• The low rate of marginal recurrence suggests that wider margins would
have little impact on the pattern of failure, validating the use of limited
margins in accordance with Adult Brain Tumor Consortium guidelines.
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94. Dr Sanjib Mishra
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The summary

95. Summary low grade
• GTV- CAVITY
• CTV- 1.0 CM FROM T2/FLAIR MRI HYPERINTENSE DISEASE
• CTV expansion is limited, in the absence of contiguous white matter tracts
• TRIMMING THE SKULL IN BONE WINDOW
• 5MM ALONG VENTRICLE AND FALX IF APPLICABLE
• INTERTAHALAMIC EXTENSION OF CTV IF NEEDED
• CTV should be limited by, without additional margin, the optic nerves and
chiasm but the optic tracts should not be excluded from the CTV
• The brainstem is an anatomical barrier only when the enhancing or
T2/FLAIR hyperintense tumor is not situated along a contiguous white
matter pathway (e.g. thalamus, internal capsule)
• Commissural tracts connect opposing cerebral hemispheres and, thus, the
CTV should cross into the contralateral hemisphere if the enhancing or
T2/FLAIR hyperintense tumor encroaches on the corpus callosum (genu
and splenium), anterior commissure, and posterior commissure
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96. Summary high grade
• GTV- CAVITY +ENHANCING AREA
• CTV- GTV+2CM AND INCLUDE FLAIR ABNORMALITY
• TRIMMING THE SKULL IN BONE WINDOW
• 5MM ALONG VENTRICLE AND FALX IF APPLICABLE
• INTERTAHALAMIC EXTENSION OF CTV IF NEEDED
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98. DO NOT DARE TO SCARE
OAR NEEDS EXTRA CARE
OTHERWISE
RARE WILL NOT BE RARE

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