Meningiomas account for approximately 35% of primary intracranial tumors, with about 90% being grade I, which typically requires complete surgical resection without the need for adjuvant radiation therapy (RT). Atypical and anaplastic meningiomas present a therapeutic challenge due to high recurrence rates, often necessitating adjuvant RT following surgery. Treatment strategies, including the use of stereotactic radiosurgery for small volume disease, are evolving, but the optimal approach remains controversial, especially for higher grade tumors.

1. Adjuvant treatment in meningioma
Debnarayan Dutta, MD
Consultant Radiation Oncologist
Apollo Speciality Cancer Hospital, Chennai

2. CBTRUS 2015
•Meningiomas account for ᷉35 % of all primary
intracranial tumors .
• Mostly slow growing
Histological types:
- Grade I ᷉90 %.
- Atypical 5-7%
- Malignant 1-3 %
Meningioma: Facts
• 90% of the meningiomas are grade I
• Suually complete surgical resection is done
• No Adj RT required
• Excellent long-term control

3. Meningioma: Gr-I
Meningioma Gr-I:
- Usually GTR done
- <5% recurrence after GTR
- Residual tumour / progression – adj RT
Usually Gr I meningiomas are observed in total or
subtotal resection done
Even in small (<1.5 cm) residual disease observation
Outcome is 80-90% LC at 10 yrs
Residual disease, 3 monthly MRI scan
Role of Adj RT only if there is progression on follow up scan
Surgery not possible

4. Meningioma: Gr-I
- Optic Nr sheath meningioma Parasagittal meningioma involving veins
• No randomized study
• No randomized study on radiation dose or fractionation
• Usually treated with 50.4Gy/28# SCRT OR 25Gy/5# fSRS or 13Gy/1# SRS
• ‘Lack of progression’ after RT is considered response

5. Meningioma: Facts
• Atypical meningiomas: therapeutic challenge
given their high recurrence rates.
• Gross total resection is done , RT reserved for
residual disease or recurrences.
• Optimal Rx of AM still controversial
Tumor recurrence rate
GTR Only- 41%
GTR and post-op EBRT - 11.8%.

6. Author Local Recurrence
Mirimanoff (MGH)
Condra (U Fl)
Stafford (Mayo)
5-yr
7%
7%
12%
10-yr
20%
20%
25%
15-yr
32%
24%
-
Gross Total Resection: High Late Relapse
May sometimes cause significant morbidity in certain sites

7. Author Local Recurrence
Wara (UCSF)
Condra (U Fl)
Stafford (Mayo)
5-yr
47%
47%
39%
10-yr
63%
60%
61%
15-yr
-
70%
-
20-yr
75%
-
-
Subtotal Resection
Challenge is to report on all consecutive patients

8. Author (year) n GTR STR STR+ RT
Mirimanoff (1985) 225 93% (n=145) 63% (n=80)
Taylor (1988) 132 96% (n=90) 43% (n=42) 85% (n=13)
Glaholm (1990) 117 84%
Miralbell (1992) 115 48% (n=79) 88% (n=17, 8yPFS)
Mahmood (1994) 254 98% (n=183) 54% (n=65) 4/6 stable disease
Goldsmith (1994) 117 89% (98% p1980, n=77)
Condra (1997) 246a 95% (n=174) 83% (n=55) 86% (n=17, 5 atypical)
Stafford (1998) 581 88% (n=465)b 61% (n=116)c
Nutting (1999) 82 92%
Vendrely (1999) 156 89% (12 >WHO grade 1)
Dufour (2001) 31 93%
a 16 atypical
b 80% of 581
c 20% of 581
5 Yr Actuarial Survivals – summary Early studies
Debus J (2005) 90.5%153
2389 88-98% 43-83% 84-98%

9. Kaur G, Neuro-Oncology, 2014
Atypical Meningioma: Recent studies 1

10. Kaur G, Neuro-Oncology, 2014
Atypical Meningioma: Recent studies 1

11. Meningioma G2: Sum ups
RT has improved PFS/ OS
RT marginally improved PFS
RT worse PFS

12. Klinger DR, World Neurosurgery, 2015
Atypical Meningioma: Factors influencing outcome
MIB Index (ki67) Mitotic Index
Region of lesion
Factors:
1. MIB Index
2. Mitotic Index
3. Resection
4. Region of lesion
5. Molecular typing

13. Sahm F, JNCI, 2016

14. Indian data
• The median dose of EBRT was 59.4 Gy (50.4Gy- 60 Gy)
• Median time to follow-up was 4.5 years (4 months–8 years)
• 41.5% (22) patients had recurrence after surgery.
• 14.5% (7 of 48 patients) who received radiotherapy developed post-RT recurrence with a
median time of 36 months (range 12 – 60 months).
• 50 patients at the time of their last follow-up had KPS of >=80% and 5 patient expired.
OSPFS
3 yrs – 91%3 yrs – 85%
Jalali R, Submitted

15. Pt required: 190
Accrual started in 22 centers

16. Response to treatment assessment
• ‘Lack of progression’ after conventional RT is considered response
• Increase in size as per RECIST criteria in considered progression
• High dose per fraction induce early regression in meningioma
• SRS (CyberKnife) induce early response with volume reduction
Pre-RT Post-RT: 6 mo
- No significant change in size of mass: stable disease

17. Anaplastic/Malignant Meningioma
PFS 2yrs PFS 5yrs
Subtotal resection 44% 0%
STR + XRT 87% 0%
Total resection 70% 28%
TR + XRT 100% 57%
Dziuk J. NeuroOnc 37: 177, 1998

18. Analastic meningioma
- Normal brain invasion criteria for anaplastic meningioma
- Usually subtotal resection
- Irrespective of total or subtotal resection: Adj RT required
- No Randomized study
- CTV margin: 2-3 cm, PTV margin: 0.5 cm
- RT dose: 60 Gy/30#
- Outcome dismal, 60-70% recurrence at 2 yr

19. RT planning: meningioma
GTV/CTV = residual tumour / tumour bed for gr II / gr III
CTV = 5 mm for benign meningiomas
2 - 3 cms for high grade meningiomas / HPC
PTV = 2mm for SRT
5mm for 3DCRT
All normal structures contoured
Dosage:
Gr-I:
54Gy/30# conformal RT
25Gy/5# / 13Gy/1#
Gr II & III meningioma:
60Gy/30#/6wks
Conformal RT
Grade I Grade II/III
Tharmoplastic mask
CT scan with contrast- 3 mm slice
MRI scan with T1 contrast & T2 flair is a must

20. Goldsmith J Neurosurg 80:195-201, 1994
0 60 120 180 240
Months
0.0
0.2
0.4
0.6
0.8
1.0
98%: RT with CT/MR (n=77)
77%: RT without CT/MR (n=40)
Progression-Free Survival
STR + postop RT; p=0.002
Impact of modern RT planning

21. Radiation therapy options
- Conventional RT
- Intensity modulated RT
- Stereotactic conformal RT
- Radiosurgery (CyberKnife)

22. Prospective cognition profile in meningiomas treated with SCRT
IQ Memory
Steinworth Radioth & Oncol 2003;69:177-82

23. SRS Vs IMRS
IMRS reduced the volume of chiasm receiving 100% of the prescribed dose from 35% to 5%,
Nakamura IJROBP 2003;55:99-109

33. Anaplastic meningioma

46. Robotic Radiosurgery
Highly precise RT delivery system
- Respiratory tracking
- Fiducial based tracking system
- Intra-fraction motion correction
- Uncomparable dose distribution
- X-ray based image verification
Hypofractionated RT
- High dose short course RT
- Higher BED delivered to target

47. Accuray Confidential
Linear
Accelerator
Manipulator
Image
Detectors
X-ray Sources
IMAGING
SYSTEM
ROBOTIC
DELIVERY
SYSTEM
TARGETING SOFTWARE

48. Cyberknife

53. ConclusionsGr I meningiomas:
Majority of the meningiomas are slow growing, Gr I
Usually complete resection possible
NO Adj RT required in majority, ONLY observation
Adj RT in progressive disease, where surgery not possible
Gr 2 meningiomas:
Role of adj RT is controversial
Pts with high MIB index, mitotic index, partial resection need adjuvant RT
Pts with TERT mutation are aggressive, high recurrence rate & need RT
Gr 3 Meningiomas:
Aggressive disease
High local recurrence
Need always adjuvant RT
Standard treatment:
Gr I: No consensus, No study between Conventional RT or SRS
Small vol disease, SRS (CyberKnife) is an option
Gr II & III: Conventional fractionation (54-60Gy)

54. Thank you
duttadeb07@gmail.com