Meningioma

Question 1

Role of RT in Grade I meningioma?

Answer 1

GTR (Simpson grade 1-3) can be followed with surveillance imaging, RT for salvage if recurrence.
STR (Simpson grade 4-5) have high recurrence rate (40% at 5 yrs) which can be halved with adjuvant RT.

Question 2

Role of RT in Grade II (atypical) meningioma?

Answer 2

Yes! Without RT, recurrence rate is 60% at 5yrs & CSS only 70% at 10yrs.
(1) RTOG 0539
GTR - 54Gy/33fx (Doubles PFS)
STR - 59.4Gy33fx or 60Gy/30fx (multiple retro studies show improves recurrence rate)

Question 3

Role of RT in Grade III (metastatic) meningioma?

Answer 3

Yes, regardless of extent of resection. <300 cases per year in US so not much data. OS is poor (<3 yrs). Minimum dose of 60 Gy recommended.

Question 4

Prospective data for meningioma?

Answer 4

Yes
RTOG 0539 (ASTRO abstract)
3 risk groups
LR = Grade 1 with GTR or STR are observed (GTR w/o RT has 5yr PFS of 40-60%, increase to 80-100% with RT)
IR = Gr2 with GTR or recurrent G1 get 54Gy/30fx to GTV+1cm CTV+3-5mm PTV.
HR = G3 any resection or Gr2 with STR or recurrent Gr2 get SIB 54Gy/30fx to GTV+2cm and 60Gy/30fx to GTV+1cm
No edema or dural tail in GTV.

Question 5

SRS for meningiomas?

Answer 5

Depends on volume and if adjacent to critical structures.

Median dose of 14 Gy, 12-16 Gy. SRS for Gr2 has good LC (80%) but marginal failure is a concern.