Ewing's

Question 1

why does ewings peak in 10-20 yrs

Answer 1

rapid bone growth during puberty

Question 2

can ewings be inherited?

Answer 2

no

Question 3

difference between intracompartmental and extracompartmental

Answer 3

bone tumors confined within the cortex of the bone

bone tumours extend beyond the bone cortex

Question 4

Stage 1A means?

Answer 4

low grade intracompartmental

Question 5

stage 2B

Answer 5

high grade extracompartmental

Question 6

what is lactic dehydrogenase

Answer 6

enzyme that helps produce energy

increased levels are associated with cell damage and can signify tumour activity

Question 7

why is it preferred to start with induction chemo

Answer 7

to see how effectiveness
shirk tumour as much as possible
bone healing may take place lowering risk of patho fracture

Question 8

why is it important to shrink tumour first

Answer 8

can decrease the vol of RT

better chance at negative margins

Question 9

if surgery not indicated then what is the plan?

Answer 9

RT and then chemo

surgery is optimal

Question 10

for small tumours on expendable bones what is the probable care path

Answer 10

RT or surgery

Question 11

for large unresectable tumours what is the probable care path

Answer 11

debulking surgery followed by RT

Question 12

what pt factors does surgery depend on

Answer 12

tumour location
age
other tx
extent of disease

Question 13

what is probable if RT fails for a tumour on an extremity

Answer 13

amputation

Question 14

what are 3 surgical options for pts with tumours of the distal femur

Answer 14

complete amputation
lumb salvage
rotationplasty

Question 15

when is RT treatment of choice

Answer 15

unresectable tumour
post op + margins
distal extremity lesions in nonexpendable bones
pelvis and spine tumours
impending pathological fracture
met disease
BMT

Question 16

total dose to GTV (coned down)

Answer 16

5580

Question 17

pre chemo dose

Answer 17

4500

Question 18

6000 cGy has similar control than standard doses why dont we use 6000 then?

Answer 18

because it showed a notable increase in secondary malignancies

Question 19

what is the margin added to GTV1 to make CTV1

Answer 19

1.5cm

Question 20

what is the margin added to CTV1 to make PTV1?

Answer 20

0.5-1cm

usual dose is 4500/25

Question 21

if pathologically involved LN are present what is the dose

Answer 21

PTV1 will receive 5040/28

Question 22

what structures/tissues are inv with GTV2

Answer 22

all pretreatment bony involvment, post chemo soft tissue disease, residual primary disease after preop RT and surgery, unresected LN

Question 23

what is the margin added to GTV2 to make CTV2?

Answer 23

1cm

Question 24

what is the margin added to CTV2 to make PTV2

Answer 24

0.5-1cm

dose usually 540/3fx

Question 25

why is there GTV1 and GTV2

Answer 25

2 indicated boost

Question 26

what is typical dose to PTV1 and PTV 2? total?

Answer 26

5040cGy
540cGy
total 5580

Question 27

what are the conventional fields sizes

Answer 27

all bony disease +2cm margin+soft tissue extension with margin
must spare uninvolved regions of soft tissue at edges to avoid lymphedema (1cm strips)

Question 28

effects of RT on femur

Answer 28

2/3 pts develop shortening of 2cm or more

1/3 develop pathologic fractures