discussed about indications of radiotherapy and execution in carcinoma maxilla, different techniques such as conventional, conformal, IMRT and VMAT.

1. Treatment Planning of Ca Maxilla

2. Patient Details
● 49Y/ Male
● C/C- non healing ulcer @rt side of hard palate since 2 yrs,
nasal obstruction- 2 months, rt eye swelling-2months
● CECT- large enhancing infiltrating mass lesion involving rt
maxilla, nasal cavity,masticator space causing osseous
destruction with locoregional extension to rt side, no midline
crossing
● Underwent rt total maxillectomy on 15 july 2016
● I/O findings- hard palate involved upto midline,posteriorly upto
soft palate, anteriorly reaching incisors
● HPR- 6*5*4 cm adenoid cystic carcinoma, PNI present, medial
and posterior margin involved by tumor

3. Indications of Post operative Radiotherapy in
CA Maxilla
● Positve resection margins
● Extracapsular nodal spread
● Close resection margins < 5mm
● Invasion of soft tissue
● >2 nodes involved
● Involved node >3cm in diameter
● Vascular invasion
● Multicentric primary
● Poor differentiation
● Stage III/IV
● Perineural invasion

4. Radiotherapy Treatment Plan
Intention – Radical
Dose/Fractionation/time- < 66Gy/33#/6 ½ wks>

5. Positioning:
● Supine position
● Head slightly hyperextended- to bring the floor of orbit parellel to
axis of anterior field
Immobilization
● To ensure accuracy in setup patient
● Should be immobilized with a custom-made thermoplastic cast

6. A-L field
Anterior
BORDER FIELD MARGIN
● Upper At supraorbital ridge( if orbit involved)
superior part of maxillary antrum( if orbit not involved)
● Lower At angle of mouth(1cm below floor of sinus)
● Medial medial canthus of opposite eye(1cm across midline)
● Lateral falling off the skin(1 cm beyond the apex of sinus)
Lateral
BORDER FIELD MARGIN
● Upper same as anterior border
● Lower
● Anterior parallel to slope of face(flash in air)
● Posterior Mastoid process

7. Anterior field:
The cornea, lens & lacrimal gland are shielded – if no gross involvement
of orbit
Cornea is spared- If there is disease in the orbit, by using pencil beam
shield
No sparing- if gross disease involved
Lateral field:
Angled 5-10 degree posteriorly to avoid the exit beam entering
opposite eye
Shielding

8. A-L field w/o wedge

9. ● A-L wedge pair

10. 2-D Planning
B/L pair
Upper- supraorbital ridge
Lower- At angle of mouth(below floor of sinus
Anterior- falling of skin
Posterior- mastoid process

12. 3 D Conformal Planning
The CTV should encompass
all initial sites of disease(presurgery GTV),
The mucosa of adjacent compartments of the sinonasal complex and
a 10 mm margin at least from initial sites of GTV where no good bony barrier to
invasion exists
(e.g. masticator space, cribriform plate and infraorbital fissure)
Bony orbit if involved
For most tumours, the CTV will include the ipsilateral maxillary
sinus and bilateral nasal cavity and the ethmoid sinuses.
The CTV is expanded isotropically (usually by 5–10 mm)to form

13. A-L wedge pair

15. B/L wedge pair with anterior field

17. IMRT
● Non uniform fluence is delivered through multiple beams giving more
uniform and conformal dose distirbution
● Inverse planning

19. DVH comparison

20. Comparison
OAR 3 D CRT (3 field) IMRT
Parotid(I/L) 44 Gy 31 Gy
Eye(I/L) 45 Gy 17 Gy(spared)
Eye(C/L) 30 Gy 6 Gy(spared)
Lens(I/L) 42 Gy 11 Gy
Lens(C/L) 38 Gy 7 Gy(spared)
Optic Chiasma 65 Gy D Max 68Gy D Max
Temporal Lobe(I/L) 23 Gy(spared) 28 Gy(spared)
Temporal Lobe(C/L) 16 Gy(spared) 9 Gy(spared)
Optic Chiasma 65 Gy D Max 54 Gy D Max(spared)
Optic Nerve(I/L) 64 Gy D Max 48 Gy D Max
Optic Nerve(C/L) 59 Gy D Max 22 Gy D Max Spared)
Brain Stem 24 Gy... 30 Gy...
Parotid(C/L) 38 Gy(spared) 17 Gy (spared)
Cochlea(I/L) 47Gy 35 Gy (spared)
Cochlea(C/L) 25 Gy(spared) 15 Gy(spared)

21. RT complications
Acute:
Loss of vision
Mucositis
skin erythema
nasal dryness
Xerostomia
Late:
Xerostomia
chronic keratitis and iritis,
optic pathway injury
osteoradionecrosis
Cataracts
SNHL
radiation induced
hypopituitarism

22. Conclusion
● Conventional planning may miss target volume
in T4 tumor
● 3 field 3DCRT adequate to cover target volume
● In and around maxilla, there are lot of OARs
● IMRT is the standard of care for sparing OARs