CNS

Question 1

RPA class

Answer 1

• I - AA, age<50, KPS>70
• II - AA, age >50, KPS>70
• III: GBM <50 yrs KPS>90 MS 18mo
• IV: GBM <50 yrs KPS<90 MS 11mo
• V: GBM >50 yrs KPS>70, MS 9 mo
• VI: GBM >50 yr, neuro deficit, KPS<70, MS 5 mo

Question 2

GBM treatment

Answer 2

Clinical trial
Max safe resection -> RT 60/2 Gy with concurrent TMZ -> adjuvant TMZ starting 1 month after RT
-concurrent TMZ dose: 75mg/m2/day x 7 days/wk
-adj dose starting 1 month after RT: 150mg/m2/day x 5 days/28 days x 6 mo

(Zofran and Bactrim MWF PPX w/ TMZ)
-take TMZ night before per Stupp

Question 3

GBM elderly

Answer 3

<70 yrs KPS high -> Stupp regimen

>70 yr wih KPS good -> TMZ + 40 Gy/15 fx – concurrent and adjuvant TMZ. (mMGMT was predictive) *>65 and ECOG 0-2*

KPS fair -> TMZ alone if MGMT methylated
-> RT alone if MGMT unmethylated (40/15 or 25/5 [Roa])

KPS very poor -> supportive care only

Question 4

GBM planning objectives and constraints

Answer 4

> 95% of PTV receives 100% of dose
Min dose to PTV 90%

Brainstem < 54 Gy (max 60 to <10 cc)
Optic chiasm/nerve < 54 Gy
Spinal cord/Retina < 45 Gy
Cochlea Dmean < 45 Gy
Lens < 10 Gy
Lacrimals < 26 Gy

Question 5

GII-III IDH wildtype treatment

Answer 5

treat like GBM

Question 6

G2 Astro treatment and OS

Answer 6

MSR ->

Low risk -> observe

High risk -> 54 Gy (T2/T1gad/cavity + 1cm) -> PCV

6y

LR: <=40y and GTR

Question 7

G3 Astro treatment and OS

Answer 7

MSR -> 59.4 Gy (T2/T1gad/cavity + 1.5cm) -> TMZ

5y

Question 8

G2 Oligo treatment and OS

Answer 8

MSR ->

Low risk -> observe

High risk -> 54 Gy (T2/T1gad/cavity + 1cm) -> PCV

14y

LR: <=40y and GTR

Question 9

G3 Oligo treatment and OS

Answer 9

MSR -> 54 Gy (T2/T1gad/cavity + 1cm) -> PCV

14y

Question 10

Meningioma pathology

Answer 10

psammoma bodies

• Benign (75-85%) – Grade I: <4 mitoses / 10 HPF
• Atypical (5-10%) – Grade II: 4-19 mitoses/ 10 HPF, or Brain invasion
• Anaplastic (<5%) – Grade III: >=20 mitoses / 10 HPF

Question 11

Grade 1 Meningioma Man

Answer 11

Grade 1 (benign):
Asx and < 3 cm: observe
-median growth 4 mm/yr

Sx, large, high risk area, progressing

1. Surgery – consider post-op RT if STR (but mostly observe)
2. Definitive RT to 54 Gy
3. Definitive SRS to 12 Gy

CTV is 1 cm along dura for Grade 1, 2-3 cm for Grade 2/3

Question 12

Grade 2 Meningioma Man

Answer 12

Grade II (atypical):
Surgery -> RT
If GTR, RT to 54 Gy (could observe if good surg salvage option)
If STR, RT to 60 Gy (RTOG 0593)

CTV is 1 cm along dura for Grade 1, 2-3 cm for Grade 2/3

Question 13

Grade 3 Meningioma Man

Answer 13

Grade III (anaplastic): 
Surgery -\> RT to 60 Gy 

No SRS for G2-3

CTV is 1 cm along dura for Grade 1, 2-3 cm for Grade 2/3

Question 14

Simpson grade resection

Answer 14

Simpson grade resection (1-3 is GTR, 4-5 is STR)
I – GTR removal bone/dura
II – GTR dural coag
III – GTR no dural coag/removal
IV – STR
V – Decompression only
**new addition of a grade 0- stripping of 2-4 cm of dura

Question 15

SRS constraints

Answer 15

SRS:
Optic chiasm: 8 Gy need 3mm to do this
Whole brain – GTV V12 < 5-10cc
Brainstem < 12 Gy
Eye/retina: 8 Gy
Cochlea: 4 Gy

Question 16

Pit Adenoma Treatment
Non-functioning:

Answer 16

No role for UPFRONT RT unless inoperable!!

Non-functioning:
Trans-sphenoidal surg (TSS)
-adj RT at 6 wks if STR or growth

EBRT 45 Gy
SRS: 15 Gy

Question 17

Pit Adenoma Treatment
ACTH or GH

Answer 17

No role for UPFRONT RT unless inoperable!!

ACTH or GH: TSS
-adj RT for persistent hormone secretion post-op or STR

EBRT 50.4 Gy
SRS: 25 Gy

Question 18

Pit Adenoma Treatment
TSH-secreting

Answer 18

No role for UPFRONT RT unless inoperable!!

TSH-secreting:
TSS -> post-op RT always (54 Gy)

Question 19

Pit Adenoma Treatment
Prolactinoma:

Answer 19

No role for UPFRONT RT unless inoperable!!

Prolactinoma: medical management (bromocriptine) first even if visual sx. Surgery for failure of medical tx.

Inoperable: RT
Recurrence after surgery: RT

Question 20

AN treatment

Answer 20

1) EBRT or SRS
both offer > 90% LC
60-70% hearing preservation (may be lower w/ SRS)

EBRT dose: 50.4/1.8 Gy (>3 cm, useful hearing, malignant (54 Gy), NF2, pressing on brainstem)

SRS dose: 12 Gy

SRT doses:
7 Gy x 3 (Stanford)
5 Gy x 4-5 (Slotman)

2) Microsurgery (translabyrinthine or middle cranial fossa or subocipital)
50% useful hearing

3) Observation: tumors grow 1-2 mm/year, so observation is always an option in someone who has already lost their hearing

Question 21

AVM dose and success

Answer 21

< 3 cm: 20 Gy to 50% IDL
> 3 cm: 16 Gy to 50% IDL

Target is nidus, not feeding arteries or draining veins

For tumors >15 cc, consider staged SRS 6 months apart

Obliteration rate 80-90% with SRS (especially if <10cc)
Median time 1-3 yrs for complete obliteration
Risk dec by 50% during latency period

Question 22

Trigeminal Neuralgia dose

Answer 22

80 Gy max; target is trigeminal nerve root; single 4 mm isocenter; brainstem edge at 20-30% IDL

Question 23

Chordoma dose

Answer 23

Max safe resection -> RT
Dose: 70 Gy (refer for protons for BOS location)

Question 24

HA- WBRT

Answer 24

HA-WBRT: 3 Gy x 10
-brain target: brain – hippocampus + 5mm, no PTV
-contour all mets – not required
-contour hippocampus + 5 mm margin
-hippocampus is grey matter
-RCT CC001 – iimproved cognitive outccomes with HA-WBRT over traditiional WBRT – ineligible if SCLC, mets within 5 mm of hippocampus, lepto
-hippocampus: max < 16 Gy, D100%<9Gy
-optics <37.5
**who gets this?

HA-WBRT+memantine:
Phase III trial of WBRT+memantine +/- HA
*HR for NCF 0.74, lower risk exec function at 4 month, encoding and consolidation at 6, pt reported faigue, speaking, and memory improved 6 months.

Question 25

SRS dose

Answer 25

≤2cm: 24 Gy (20 Gy)

2. 1-3 cm: 18 Gy
3. 1-4 cm: 15 Gy (or 6 Gy x 5)