Background and recommendations

Question 1

What dose do you provide when giving larynx only RT?

Answer 1

1. T1 N0 = 63 Gy at 2.25 Gy/fx (28)

2. T2 N0 = 65.25 at 2.25 Gy/fx (29)

Question 2

What are the indications for treating glottic CIS?

Answer 2

1. Recurrence
2. Involvement of anterior commisure
3. Patient is unreliable for close follow up
4. Medically high risk for surgery

Question 3

What are the borders of larynx only fields for glottic cancer?

Answer 3

Sup: Midthryoid notch
Ant: flash by 2 cm
Inf: bottom of cricoid or 1 cm below if subglottic extension is noted
Posterior: ant edge of VB

Question 4

T1 glottic

Answer 4

a. Tumor involves glottis only, 1 cord

b. Tumor involves glottis only, 2 cords

Question 5

T2 glottic

Answer 5

1. Tumor involves supra or subglottis

2. impaired cord mobility

Question 6

T3 glottic

Answer 6

Fixed cord
Paraglottic space invasion
Only inner cortex T-cartilage invasion

Question 7

T4 glottic

Answer 7

Full thickness T-cartilage invasion 
Deep tongue invasion
Trachea invasion 
Soft tissues of neck invasion 
Esophageal invasions
Thyroid invasion

Question 8

What are the indications for ENI for larynx cancer?

Answer 8

1. All supraglottic cancers

2. All cancers with > 5 mm subglottic or supraglottic extension

Question 9

What nodes should be covered with ENI?

Answer 9

Unilateral

1. RS in node positive neck
2. RP in node positive neck or if tumor involves PPW (bilaterally)
3. Level 5 in node positive neck

Always bilateral
2, 3, 4, 6, 7

Question 10

When do you use a LAN?

Answer 10

Never. Just use whole neck IMRT.

Question 11

What beam energy is preferred?

Answer 11

4 MV but 6 MV can be just as good but close attention must be paid to isodose lines

Question 12

How do you weight the beams for larynx only RT with unilateral tumor?

Answer 12

3:2

Question 13

What tumor volume do you use for supraglottic cancers when deciding surgery vs. RT?

Answer 13

12 cc

Question 14

What equation approximates tumor volume?

Answer 14

4/3 x Pi x r^3 = Volume of sphere

Question 15

T1 supraglottic

Answer 15

Limited to one subsite of supraglottis

Question 16

T2 supraglottic

Answer 16

More than one subsite of supraglottis or involvement of the glottis, vallecula, tongue mucosa, medial wall of pyriform sinus

Question 17

T3 supraglottic

Answer 17

fixed cord, paraglottic space invasion, invasion of inner cortx of the Tcartilage, invason of the post-cricoid area, invasion of the pre-epiglottic space

Question 18

T4 supraglottic

Answer 18

Full thickness T-cartilage invasion 
Deep tongue invasion
Trachea invasion 
Soft tissues of neck invasion 
Esophageal invasions
Thyroid invasion

Question 19

CT simulation

Answer 19

1. Supine
2. Arms down, Qfix
3. IV contrast
4. Aquaplast mask
5. Neck extended