Background and treatment

Question 1

Median age for sporadic cases

Answer 1

40-50

Question 2

How do intracanilicular meningiomas present?

Answer 2

Less widening of the IAC Meningiomas usually cause hyperostosis

Question 3

What is the growth rate for untreated lesions?

Answer 3

2.9 mm/year

Question 4

What percentage of patients with schwannomas have NF2?

Answer 4

10%

Question 5

What is the median age of patients with NF2 to develop schwannomas?

Answer 5

30-40s

Question 6

What condition is suggested in patients with bilateral acoustic neuromas?

Answer 6

NF 2

Question 7

What elements of the history should be acquired?

Answer 7

Hx: Hearing loss, loss of balance or vertigo, facial weakness, facial numbness, headache, tinnitus Physical exam: CN exam

Question 8

What imaging and labs are needed at work up?

Answer 8

Imaging: MRI brain with contrast with thin cuts through CPA angle MRI of spine if NF is suspected

Question 9

What other studies are needed at work up?

Answer 9

Pure tone and speech audiometry

Question 10

What are treatment options?

Answer 10

1. Observation 2. Microsurgery 3. SRS 4. Fractionated RT

Question 11

What is the size cut off for SRS?

Answer 11

3 cm

Question 12

What do you recommened if a STR is performed?

Answer 12

Fractionated PORT

Question 13

What is the recommended dose for fractionated RT?

Answer 13

50.4 Gy at 1.8 Gy/fx

Question 14

What are the volumes for SRT?

Answer 14

GTV + 0.5 cm = PTV

Question 15

What is the rate of hearing preservation if observing for 3-5 years? Is there a growth rate that predicts hearing preservation?

Answer 15

Sughrue et al 54% 2.5 mm

Question 16

Dose constraint for cochlea with SRS?

Answer 16

Cochlea: 9 Gy in 1 fraction

Question 17

What are the surgical approaches used for treatment?

Answer 17

Middle cranial fossa: small < 1 cm, or intracanalicular Translabrynthine: it sacrifices hearing Suboccipital: large, medial tumors.

Question 18

What is the recommended SRS dose?

Answer 18

12.5 Gy in 1 fraction

Question 19

What is the likelihood of local control with RT?

Answer 19

SRS: 98% RT: 96%

Question 20

What is the likelihood of hearing preservation after surgery? CN V and VII?

Answer 20

14-46% V: 78% VII: 65%

Question 21

What is the preservation of hearing for patients treated with SRS? CN VII? CN V?

Answer 21

Hearing: 43-73% CN VII: >90% CN V: 90%

Question 22

What is the preservation of hearing for patients treated with fractionated RT? CN VII? CN V?

Answer 22

Hearing: 63-100% CN VII: >90% CN V: 95%