Hats and Scarves 2

Question 1

What are the general signs and symptoms of Head and neck cancer?

Answer 1

Pain/ soreness
Difficulty swallowing (dysphagia)
Neck mass
Voice changes

Question 2

Classic patient presentation vs New patient presentation?

Answer 2

Generally older males
Significant history of smoking and drinking
Generally, don’t look after themselves
VS
Younger
Generally better socio-economic status
Limited or no previous smoking or alcohol history
Now make up majority of head and neck cancer population

Question 3

Immobilization devices

Answer 3

Thermoplastic mask
Standard head rests/ custom ( e.g. 2 part foam)
Vac loc bags
Shoulder supports/fixation
Hand grips
Mouthpieces/ mouth bites

Question 4

Purpose of mouthpiece

Answer 4

keeps tongue in/out of field, can improve immobilisation

Question 5

Purpose of Shoulder retractors/ fixation?

Answer 5

can affect shoulders in field, relax, weight loss

Question 6

What are the important aspects of immobilisation for a head and neck patient?

Answer 6

adequate neck support
intricate moulding of shell around important anatomical features and anomalies (i.e. nose, ears, chin, sup of skull)
chin position 
shoulder position 
shell integrity

Question 7

What are the CT simulation considerations for head and neck patients?

Answer 7

length of time elapsed after surgery (potential residual swelling, tenderness, wound healing)
Dentures and plates
Dental extractions required (important this is done prior to planning due to its effect on patient positioning)

Question 8

What are the CT simulation problems?

Answer 8

anatomical and surgical anomalies
claustrophobia
no teeth!
Tracheostomy
Potential shell shrinkage

Question 9

What are the imaging requirements for Head and Neck CT simulation?

Answer 9

Ensure all appropriate marks are on the patient  CT zero/PR marks
 Nodal areas
 Scars
 Bolus (some centres scan with bolus on)
 IV contrast
 Ensure the entire potential treatment area is imaged
 Important to remember basic CT principles
 Don’t alter kV settings due to impact on HU value and dose
calculation
 FOV size
 Image artifacts

Question 10

What are the final considerations for CT simulation?

Answer 10

ensure all marks are on patient shell
comprehensive record of position (devices, positioning measurements- ITN position, C-SSN)
Other pertinent information (photos)

Question 11

What are the most common conventional fractionations for head and neck cancer (3DCRT)?

Answer 11

70Gy in 35# to high risk area
50Gy in 25# to elective areas
sometimes 54-60Gy in 27-30# to intermediate areas

Question 12

What are the most common IMRT fractionations?

Answer 12

70Gy in 35# to high risk area
56Gy in 35# to elective areas
63Gy in 35# to intermediate areas

Question 13

What is the common post-operative fractionation

Answer 13

66Gy in 33# to positive margin area

54-60Gy in 27-30# to operative bed

Question 14

What is the DAHANCA protocol for head and neck cancer?

Answer 14

68Gy in 34# (2Gy boost given once per week for final 4 weeks of phase 1 and remaining 5# delivered immediately after the completion of phase 1)
For IMRT: bi-daily treatment once per week in last 4 weeks of treatment

Question 15

Why use altered fractionation dose schedules?

Answer 15

• Both dose per fraction and irradiation time influence the response to radiation of malignant tumours and acute-responding tissues
• Altered fractionation radiotherapy improves survival in head and neck patients. Comparison of the different types of altered radiotherapy suggests that hyper fractionation provides the greatest benefit
• consider treatment side effects

Question 16

What are the surrounding OAR in head and neck treatment?

Answer 16

spinal cord
brainstem
parotid glands
lenses
optic nerves
optic chiasm

Question 17

Dose to spinal cord?

Answer 17

45Gy

Question 18

Dose to brainstem?

Answer 18

max <54Gy

Question 19

Dose to parotids?

Answer 19

26-30Gy median dose

Question 20

Dose to Lenses?

Answer 20

6-8Gy

Question 21

Dose to optic nerves?

Answer 21

50.4Gy

Question 22

Dose to optic chasm?

Answer 22

54Gy

Question 23

What is the field arrangement for larynx?

Answer 23

opposing lateral fields
generally requires bolus on anterior surface
Field placement considerations (collimation along angle of spinal cord, shoulder position)

Question 24

What is a typical field arrangement for unilateral volumes for head and neck cancer (e.g. parotid)?

Answer 24

3 -field arrangement
Traditional wedged pair
Generally include lower neck therefore junction required

Question 25

What is a typical field arrangement for Bilateral volumes for head and neck cancer (e.g. oropharyngeal tumour)?

Answer 25

multi field arrangement (anterior, anterior obliques, posterior obliques)
Junctioning technique
Parotid sparing technique
For lower neck : anterior +/- posterior beam
Field weightings: deliver as much dose as possible through the large anterior field and use obliques to keep to spinal cord tolerance

Question 26

Bilateral face (parotid sparing)

Answer 26

multi field arrangement (6-8 fields)
Split posterior, posterior obliques, laterals, anterior obliques
Lateral fields given largest weighting
Posterior and posterior obliques used to come off spinal cord

Question 27

What do you need to consider with lenses?

Answer 27

exit beam

Question 28

IMRT for Head and Neck?

Answer 28

gold standard treatment for complex, radical head and neck cancer
7-9 beams
no opposing fields with IMRT

Question 29

What are the two types of IMRT?

Answer 29

static (step and shoot)
Dynamic (sliding window)
(refers to the way the MLCs move during treatment)

Question 30

What are the benefits of VMAT compared to IMRT?

Answer 30

Potential benefits with VMAT compared to IMRT are obtained through enhanced flexibility in delivery by facilitating alternating dose rate and gantry speed during dynamic movement of jaws and MLCs
Provide more conformal dose distribution than conventional techniques
Provides steep dose gradients (or dose drop off) between different areas
Very beneficial for tumours that are prescribed a high dose but are in close proximity to critical structures.
Generally 2x 360degree

Question 31

After applying the specific dose constraints to each structure which are given the highest priority for IMRT/VMAT?

Answer 31

PTV should always be of high priority followed by critical structures.

Question 32

What are the implications of IMRT/ VMAT?

Answer 32

increased potential of over and underusing of tumour volume and critical structures
importance of accurate and reproducible patient positioning
importance of target and critical structure margins

Question 33

How many phases of treatment are typical for head and neck patients?

Answer 33

2 -phases
Therefore, don’t take all critical structures to tolerance in first phase
Multiple phases treated simultaneously