pit-190330014429.pdf

1. RADIOTHERAPY PLANNING PITUITARY ADENOMA DR KANHU CHARAN PATRO RADIATION ONCOLOGIST 3/30/2019 1

2. SLOW MY FLOW • INTRODUCTION • CASE SELECTION AND INDICATION • PRE RADIOTHERAPY EVALUATION • IMMOBILIZATION • IMAGING • FUSION • TARGET DELINEATION [GTV, CTV, PTV] • DOSE PRESCRIPTION[TARGET, OAR] • PLANNING • EVALUATION • EXECUTION • MONITORING • FOLLOW UP • OUTCOME 3/30/2019 2

3. INTRODUCTION • Pituitary adenomas are mostly benign tumours and comprise about 10% of all intracranial tumours • Radiotherapy has an important and long- established role as part of the multi-disciplinary management of both non-functioning and functioning adenomas. 3/30/2019 3

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6. INDICATION • Functioning/secretory adenoma – When medical therapy fails • Macro-adenomas – Causing vision problems – Compressing symptoms 3/30/2019 6 Radiation therapy should be considered in the management of patients with pituitary adenomas, particularly when medical and surgical options have been exhausted

7. INDICATIONS 3/30/2019 7 1. Significant residual (consider redo TSS first) 2. Very large silent corticotroph (increased risk of recurrence post-operatively) 3. Atypical histology o Recurrent (ie following a second TSS or within the cavernous sinuses) 4. Hormone secreting (not cured biochemically surgically) 5. Medically unfit patients: Long-term control rates are around 70-80% with radiotherapy alone

8. RADIATION IN PITUITARY ADENOMA 3/30/2019 8 1. It works slowly, so it can take months or even years before the tumor growth and/or excess hormone production is fully controlled. 2. It can damage the remaining normal pituitary. 3. In many cases, normal pituitary function will be lost over time, so treatment with hormones will be needed. 4. It may damage some normal brain tissue, particularly near the pituitary gland, which could affect mental function years later. 5. The optic apparatus may be damaged, causing vision changes. 6. The radiation may increase the risk of developing a brain tumor later in life, but this risk is low in adults.

10. ENDOCRINE EVALUATION 3/30/2019 10

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13. VISUAL ACUITY 3/30/2019 13

14. SURGERY 3/30/2019 14

15. HORMONAL TREATMENT DETAILS 3/30/2019 15

17. SIMULATION POSITIONING SUPINE/NEUTRAL POSITION HANDS LATERAL MASK 3 CLAMP HEAD AND NECK HEAD REST FLEX /NEUTRAL INVASIVE STEREOTAXY MASK NON INVASIVE STEREOTAXY MASK 3/30/2019 17

18. ORFIT/MASK 3/30/2019 18

19. CUSTOM MADE MASK 3/30/2019 19

20. NON INVASIVE STEREOTACTIC MASK 3/30/2019 20

21. INVASIVE STEREOTACTIC MASK 3/30/2019 21

22. CHOOSING THE HEAD REST 3/30/2019 22

23. NECK SUPPORT WITH FLEXION (NRF) 3/30/2019 23

24. ERRORS WITH FLEXON NECK SUPPORT Neck support with flexion leads with significantly higher setup errors in the ML and AP directions. Differential PTV margin for the ML and AP directions may be considered for patients undergoing treatment with flexion supports 3/30/2019 24

26. IMAGING PREFERENCES PITUITARY ADENOMA CT SCAN 1. CONTRAST CT BRAIN 2. 3MM OR LESS MRI 1. CONTRAST MRI BRAIN 2. 3mm OR LESS GENERALLY T1 AND CONTRAST PACKING MATERIAL FATSAT SEQUENCE OPTIC CHIASM IDENTIFICATION CISS/IR SEQUENCE CAVERNOUS SINUS DIFFERENTIATION T2 AND FLAIR 3/30/2019 26

27. GENERAL PRINCIPLE 3/30/2019 27 1.The coronal plane offers the best single view for assessing the sella and allows the pituitary gland to be distinguished from the surrounding structures 2.Sagittal views are particularly helpful for evaluating midline structures. Because the pituitary gland is small, high spatial resolution images are required 3.Fat-saturation techniques are useful for postoperative evaluations

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30. CAVERNOUS SINUS CAROTID ARTERY OPTI C CHIASMA INFUNDIBULUM PITUITARY 3/30/2019 30

31. INFUNDIBULAR RECESS SUPRA OPTIC RECESS OPTI C CHIASMA INFUNDIBULUM PITUITARY 3/30/2019 31

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35. NORMAL PITUITARY- MRI PICTURES The adenohypophysis is isointense & the neurohypophysis is hyperintense- T1 PLANE Sagittal postcontrast T1shows normal diffuse enhancement of the gland 3/30/2019 35

36. PITUITARY MICROADENOMA- MRI PICTURES LEFT PART PITUITARY GLAND. WITHIN THE GLAND, A FOCAL AREA OF HYPOINTENSITY IS SEEN IN T1 PLANE Microadenoma remains hypointense while the remainder of the gland enhances IN T1 CONT 3/30/2019 36

37. DELAYED IMAGE 3/30/2019 37 1. Imaging more than 30 minutes after intravenous contrast also may help detect Microadenomas, which then appear as focal hyperintense lesions relative to the surrounding gland. 2. Encasement of the intercavernous internal carotid artery by adenoma greater than or equal to 67% was concluded to be a specific sign of a cavernous sinus invasion in one study. 3. Fat packed in the surgical defect appears hyperintense on T1- weighted sequences and requires the use of fat-saturated sequences to distinguish contrast enhancement from packing material

38. PITUITARY MACROADENOMA- MRI PICTURES There is a well defined round lesion noted in the pituitary fossa, the lesion is homogeneous and isodense on T1 There is a well defined homogeneously enhancing lesion in the pituitary fossa on Sagittal T1 C+ suggestive of pituitary adenoma 3/30/2019 38

39. CONVEX UPPER MARGIN IN PUBERTY 3/30/2019 39

40. LOCATION OF THE TUMOR 3/30/2019 40 1. Tumors secreting ACTH, thyroid stimulating hormone, luteinizing hormone, and follicle stimulating hormone are found centrally within the pituitary gland 2. While prolactin and growth hormone adenomas occur at the periphery

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68. WITH PARASELLAR EXTENSION 3/30/2019 68

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70. HARDY’S CLASSIFICATION 3/30/2019 70

71. RIGHT CAVERNOUS SINUS INVOLVEMENT 3/30/2019 71

72. KNOSP CLASSIFICATION 3/30/2019 72

73. CAVERNOUS SINUS INVOLVEMENT 3/30/2019 73

75. IMAGE FUSION 1. Soft tissue extension 2. Delineating optic apparatus 3. Differentiating packing material 4. Differentiating cavernous sinus from tumor 3/30/2019 75

76. DIFFERENTIATING PACKING MATERIAL 3/30/2019 76

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80. DIFFERENTIATING FROM CAVERNOUS 3/30/2019 80

81. DIFFERENTIATING FROM CAVERNOUS PITUITARY ADENOMA-MRI SEQUENCE 1. WITH CONTRAST MRI PITUITARY AS WELL CAVERNOUS SINUS BOTH ENHANCE. 2. T2 FLAIR SEQUENCE IS REQUIRED TO DIFFERENTIATE PITUITARY FROM CAVERNOUS SINUS. 3. IN T2 CAVERNOUS SINUS LOOKS HYPOINTENSE 3/30/2019 81

83. TARGET VOLUMES-GCP PARAMETER GTV The tumor bed as defined as the enhancing mass on the post-contrast T1-MRI CTV CTV = GTV TMH - 0.5 cm PTV GTV /CTV + 3.0–5.0 mm, depending on setup error and the reproducibility of patient positioning 3/30/2019 83

84. PITUITARY SPARING 3/30/2019 84

85. LONDON CANCER GUIDELINES 3/30/2019 85

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87. IDENTIFYING PITUITARY • It is oval-shaped (craniocaudally up to 12 mm) and lies in the sella turcica. • Laterally, the pituitary gland is bordered by the cavernous sinuses, which are well visible with intravenous contrast agent, it is just inferior to the brain, and is connected to the hypothalamus by its pituitary stalk. • The borders of the pituitary gland can be defined best in the sagittal view . • Alternatively, the inner part of the sella turcica can be used as a surrogate anatomical bony structure • Best identified using bone 1500/950 or soft tissue 350/50 WL/WW on CT 3/30/2019 87

88. IDENTIFYING OPTIC CHIASM • The optic chiasm (14 mm transverse, 8 mm antero-posterior and 2–5 mm thick) is located 1 cm superior to the pituitary gland, which has high signal on T1 MRI, and just • Anterior to the pituitary stalk (located above the sella turcica). • The lateral border is the internal carotid artery. • The chiasm is superiorly located in the antero-inferior part of the third ventricle, below the supra-optic recess and above the infundibular recess of the third ventricle, with the optic nerves in front and the divergence of the optic tracts behind. • The anterior cerebral arteries and the anterior communicating artery are located ventral to the chiasm 3/30/2019 88

89. SLOW MY FLOW • INTRODUCTION • CASE SELECTION AND INDICATION • PRE RADIOTHERAPY EVALUATION • IMMOBILIZATION • IMAGING • FUSION • TARGET DELINEATION [GTV, CTV, PTV] • DOSE PRESCRIPTION[TARGET, OAR] • PLANNING • EVALUATION • EXECUTION • MONITORING • FOLLOW UP • TOXICITY • OUTCOME 3/30/2019 89

90. WHAT SHOULD BE THE DOSE? 3/30/2019 90 UNIVERSITY OF FLORIDA EXPERIENCE

91. DOSE COMPARISON 3/30/2019 91

92. TARGET DOSE 3/30/2019 92 1. Radiation dose was not significantly predictive of control in our experience with a narrow dose range. 2. No benefit to doses greater than 45 Gy confirms our earlier experience. 3. In light of previous studies confirming the need for at least 40 Gy and other reports suggesting superiority for 50 Gy, 4. we will continue to recommend 45 Gy because it remains the lowest dose with proven efficacy. 5. Our experience shows no dose response above 45 Gy. This may be particularly important for analysis of sequelae in the future.

93. OAR CONSTRAINTS 3/30/2019 93

94. SLOW MY FLOW 1. INTRODUCTION 2. CASE SELECTION AND INDICATION 3. PRE RADIOTHERAPY EVALUATION 4. IMMOBILIZATION 5. IMAGING 6. FUSION 7. TARGET DELINEATION [GTV, CTV, PTV] 8. DOSE PRESCRIPTION[TARGET, OAR] 9. PLANNING 10. EVALUATION 11. EXECUTION 12. MONITORING 13. FOLLOW UP 14. TOXICITY 15. OUTCOME 3/30/2019 94

95. PLANNING 1.General planning strategies include 3D-CRT, IMRT 2.VMAT depending on the orientation, location, and size of the tumor. 3.The typical energy used is 6 MV photons or higher 3/30/2019 95

96. CLASSICAL 2D PLAN 3/30/2019 96

97. IMRT PLAN 3/30/2019 97

98. ARC PALN 3/30/2019 98

99. CONSIDERATION OF STEREOTAXY 1. Commonly not practiced 1. Conventional results are best 2. Close proximity to chiasm 2. Functional tumors need higher dose16–25 Gy in a single fraction prescribed to at least the 50 % isodose line. Higher doses are preferred 3. Nonfunctional tumors: 14–16 Gy in a singlefraction prescribed to at least the 50 % isodose line, 4. Fractionated radiation therapy is recommended for tumors in close proximity to the optic chiasm (3 mm) or with marked extension into the cavernous sinus 3/30/2019 99

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101. THE DISTANCE 3/30/2019 101

102. FSRT FOR PITUITARY • Stereotactic radiotherapy originally referred to radiotherapy treatment delivered to an intracranial target lesion that was located by stereotactic means in a patient immobilised in a neurosurgical stereotactic head frame. The improved patient immobilisation, more accurate • Tumour target localisation using cross-sectional image for treatment planning, and high precision radiation treatment delivery to the tumour target, enabled a reduction in the margins around the radiotherapy target volume (the GTV to PTV margin), therefore achieving greater sparing of surrounding normal tissues than can be obtained with standard CRT techniques 3/30/2019 102

103. SCRT VS SRT • While SCRT is suitable for the treatment of all pituitary tumours, irrespective of size, shape or proximity to critical normal tissue structures, • SRS is only suitable for treatment of small tumours away from the optic chiasm 3/30/2019 103

106. IGRT IGRT examples commonly integrated into treatment units and utilized when treating CNS tumors include orthogonal KV X-rays and volume-based cone-beam CTs. 3/30/2019 106

108. DISCONTINUOUS OF HORMONAL THERAPY Discontinuation of pituitary suppressive medications at least 1 month before radiosurgery significantly improved endocrine outcomes for patients with acromegaly B. E. Pollock et al J. Neurosurg. / Volume 106 / May, 2007 3/30/2019 108

110. FOLLOW UP • 3 MONTHLY FIRST 2 YEARS THEN 6 MONTHLY • HORMONAL CHECK UP FOR NORMALIZATION • HORMONAL CHECK UP FOR INSUFFICIENCY • OPHTHALMIC EVALUATION FOR RECOVERY • OPHTHALMIC EVALUATION FOR NEURITIS 3/30/2019 110

111. FOLLOW UP IMAGING • BASELINE EVALUATION AT 3 MONTH OF POST RADIATION • MRI PREFERRED • FURTHER IMAGING AT SYMPTOMATIC PROGRESSION 3/30/2019 111

113. VISUAL COMPLICATION 3/30/2019 113

114. OPTIC NEUROPATHY • Usual radiotherapy doses are 45 to 50Gy range. • This dose is below the tolerance of optic pathway including optic chiasm. • It allows for the treatment of pituitary adenomas of all sizes, including large tumors with suprasellar extension frequently encasing or in close proximity to the optic apparatus. • The toxicity of fractionated external beam RT is low, with a 1.5% risk of radiation-induced optic neuropathy • 0.2% risk of necrosis of normal brain structures 3/30/2019 114

115. PITUITARY INSUFFICIENCY  The most frequent late morbidity of radiation is hypopituitarism likely to be primarily the result of hypothalamic injury, although direct effect on the pituitary gland cannot be excluded.  In patients who have normal pituitary function around the time of RT, hormone replacement therapy is required in 20% to 40% at 10 years 3/30/2019 115

117. A. The 10-year PFS reported in seven large series of conventional external beam RT for pituitary adenoma is 80% to 94% . B. In the largest series of 411 patients, the 10- year PFS was 94% at 10 years and 89% at 20 years 3/30/2019 117

118. HORMONAL CONTROL 3/30/2019 118

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121. CONTROL AFTER STEREOTAXY Patients with GH–producing pituitary adenomas should not undergo further radiation therapy or surgery for at least 5 years after radiosurgery because GH and IGF-I levels continue to normalize over that interval 3/30/2019 121

122. RADIOSURGERY OUTCOMES 3/30/2019 122

123. SRS SERIES FOR GROWTH HORMONE 3/30/2019 123

124. SRS SERIES FOR ACTH 3/30/2019 124

125. SRS SERIES FOR PROLACTINOMA 3/30/2019 125

126. PROLACTINOMA IS MORE RADIO-RESISTANCE 3/30/2019 126

127. TUMOR CONTROL 3/30/2019 127

128. DISEASE CONTROL 3/30/2019 128

129. LITERATURE REVIEW 3/30/2019 129

130. PATIENT COUNSELING 3/30/2019 130

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