The document summarizes radiation techniques used in treating nasopharyngeal carcinoma. It discusses 2D planning techniques including field borders and portals. It also discusses 3D conformal radiation therapy and intensity-modulated radiation therapy (IMRT), noting that IMRT allows a high dose to the tumor while limiting dose to surrounding tissues. The document reviews studies showing improved local control and reduced toxicity with 3D and IMRT techniques compared to 2D planning. It also discusses dose escalation techniques including brachytherapy and stereotactic radiosurgery boosts as well as altered fractionation schedules.

1. RT TECHNIQUES IN
CA NASOPHARYNX
PRESENTER: DR. KAVITA SEHRAWAT
PG 3RD YEAR
DEPTT OF RADIATION ONCOLOGY
MAMC AND LNH
MODERATOR: DR. NEHA
DR. WINEETA

2. TOPICS TO BE COVERED
• 2-D PLANNING WITH EVIDENCE
• 3-D PLANNING
• IMRT WITH EVIDENCE
• BRACHYTHERPY
• DOSE CONSTRAINTS
• SEQUELAE

3. RADIATION
TECHNIQUE
• BRACHYTHERAPY
• EBRT
• Co-60 (1.25MeV) - 2 D Treatment
• LINAC (4-6 MeV) –
• 3 D CRT
• IMRT

4. 2-D TREATMENT PLANNING
• Assessment of the primary disease
• Immobilization
• CT scanning
• Simulator

5. PORTALS
• Initial phase
• Two parallel opposing fields
• Three field approach
• Boost phase
• Ho’s technique(with separate parapharyngeal
boost)
• Anterolateral wedge pair technique
• Fletcher’s technique (4-field with antral boost)

6. BORDERS OF TWO FIELD APPROACH
- PHASE 1 (44GY/22#)
• Superior
• Splitting the pituitary fossa and
extending along the sup.
Surface of sphenoid sinus
• 1 cm above pituitary fossa (IC
Extension)
• Anterior
• 2 cm margin to gross tumor
extent
• Posterior
• match with tips of spinous
process of Cervical vertebra
• Flash (Gross Cervical LAD)
• Inferior
• Just above the arytenoids

7. BORDERS OF THREE FIELD APPROACH
–PHASE 11(16GY/8 #)
• 2 lateral opposed fields and one ant-facial field for NPx
• One ant cervical field for whole neck
• Superior and anterior boundaries – same
• Inferior border- Thyroid notch (no cervical LAD)
• Posterior border – Jxn of post 1/3rd and ant 2/3rd of
vertebral bodies

8. ANTERIOR FACIAL FIELD
• angled superiorly.
• Inferior border –
• At the level of the
anterior
commissure of lip.
(to about the level
of the midtonsillar
fossa)
C: Coronal view of
anterior facial field (III).
B: Phase II, sagittal view
showing lateral-opposed
facial fields and noncoplanar
anterior facial field (III).

9. LOW ANTERIOR CERVICAL FIELD
• Superior border –
• Inferior border of lateral
portals
• Inferior border –
• 1cm below the clavicle
• Lateral border –
• Include medial 2/3rd of the
clavicle.
• Midline block is used to shield
the larynx and oesophageal
inlet
D: Anterior cervical field for whole neck (IV).

10. BOOST
• Superior border:
adjusted to exclude the optic nerves, chiasm and
optic tracts after a dose of 54 Gy.
• Anterior border:
1-1.5 cm beyond gross disease.
• Posterior border:
over posterior 1/3rd of vertebral bodies.
• Inferior border:
depends on nodal status. If N0, the inferior border
is at the level of the midtonsillar fossa . If upper neck is
involved, the border is above the arytenoids.

11. NECK NODE BOOST
• Photons
• Electrons
• Four- field

12. HO’S TECHNIQUE : PLANNING
• Three field arrangement:
• Opposed lateral fields irradiate
the upper cervical lymphatics (
upto level III) en bloc.
• An anterior field irradiates the
lower field.
• Shielding of the lateral fields is
done to adjust for the beam
overlap with the anterior field.
• In the lower anterior field a
midline shield is placed
throughout the treatment.
Bisecting the
maxillary antrum
0.5 cm above the
anterior clinoid
process
Below vocal cords C6

13. HO’S TECHNIQUE : PLANNING
• Specialized arrangement of shielding is done for
all patients.
• Brain Stem: Shielded with 5 HVL block placed in a
manner such that it is 0.5 cm behind the upper edge
of the clivus and 1 cm below the lower edge.
• Eye: 5 HVL shield placed 1.5 cm behind the lateral
canthus.
• Posterior tongue also shielded with standard block.
• Pituitary and temporal lobes: upper half of the
pituitary fossa shielded.

14. • Prescription recommended for NPC –
• 70 Gy over 7 weeks to the gross tumor
• Along with 50 to 60 Gy for elective treatment of potential risk
sites.

15. RADIATION
TECHNIQUE
• Conventional 2D
• 3D Conformal :NPC presents most typically as a concave
tumor, allowing for computerized three-dimensional (3D)
treatment plans to be an important technical advance for
improved radiation delivery
• IMRT: supplanted conventional radiotherapy in the treatment
of NPC & is preferred for NPC
 The intensity of the radiation beams can be modulated to
deliver a high dose to the tumor with a superior target
volume coverage while significantly limiting the dose to
surrounding normal structures

16. IMPACT OF DOSE
Prescription recommended
70 Gy to the gross tumor @1.8-2 Gy/#
50-60 Gy to potential risk sites @1.8-2Gy/#
• Retrospective studies :T1-2 tumors had good local control rate
90-100% for >70 Gy, compared to 80% for 66 to 70 Gy
• local control with T3-4 tumours remained <55%, even with total
>70 Gy
• Higher doses did not significantly improve outcomes in
T3-4 tumors
• These observations suggest that, besides consideration

17. IMPACT OF TIME &
FRACTIONATION
• Benefit of accelerated fractionation - uncertain (no benefit in local control,
increased toxicities)
• Retrospective study by Lee et al. in 1,008 patients with T1 tumours irradiated
by 4 different fractionation schedules demonstrated that total dose was the
most important radiation factor (p = .01)
• Dose per fraction did not affect local control; however, it was a significant risk
factor for temporal lobe necrosis
• fractional dose of >2-2.12 Gy should be avoided
• Vikram et al.- interruption of RT for > 21 days had significantly poorer local
tumor control
• Prolongation is likely to detrimental

18. DOSE ESCALATION
• Additional boost to pt. with early disease
treated by 2-D technique- excellent local
tumor control
Brachytherapy
Stereotactic radiosurgery
Altered fractionation

19. BRACHYTHERAPY
• As a boost for T3 T4 patients after EBRT
• Treatment of recurrent disease
• Intracavitory/ interstitial implants

20. • summarizes reports on the use of brachytherapy as a boost for dose
escalation.
• Most studies demonstrated that local control of up to 90% to 95%
could be achieved for T1-2 tumors without excessive late damages

21. Rotterdam
nasopharyngeal applicator
Position of the radioactive sources and the
dose distribution

22. • 275 patients with loco regionally advanced NPC disease
(TNM stages III or M0 stage IV)
• treated by induction chemotherapy f/b concurrent
chemoradiotherapy to 70 Gy conventional planning
• NACT :cisplatin: 100 mg/m2 and doxorubicin 50 mg/m2 or
Epirubicin 75 mg/m2 3 weeks for 2 cycles followed by EBRT
70 Gy to primary & positive nodes & 46 Gy to negative neck
and concurrent weekly cisplatin 30 mg/m2 /week for 7
weeks
• 2 arms
 Arm A:standard arm
 Arm B:brachytherapy boost arm: received boost of 11-Gy LDR
or three fractions of 3-Gy HDR

23. Results:
• With a median follow-up of 29 months no additional benefit of
brachytherapy boost compared with chemoradiotherapy alone
alone
 distant-metastasis–free survival (52.6% vs. 59.8%, p = .496)
 3-year OS (63.3% vs. 62.9%, p = .742) .
 locoregional-FFR (54.4% vs. 60.5%, p = .647)
• The addition of a brachytherapy boost to external beam
radiotherapy and chemotherapy did not improve outcome in
loco-regionally advanced nasopharyngeal carcinoma

24. • Drawbacks:
not suitable for treatment of tumors with
intracranial extension because of the rapid
reduction of dose as distance from the
source increases
adequate only for superficial (<10mm), non-bulky
tumors
depends upon individual clinician’s skills
• Since the advent of IMRT as primary radiotherapy for
nasopharyngeal carcinoma and with its excellent local
control, the use of brachytherapy as a boost
following definitive EBRT has declined

25. STEREOTACTIC
RADIOTHERAPY
• Precise delivery of highly conformal RT with rapid dose falloff
• Ilara et al.
• 82 pts with T1 to T4 tumors
• 5 yr L-FFR – 98 % after receiving a median SRT boost of 12 Gy
f/b EBRT to 66 Gy
• Despite the addition of concurrent chemotherapy in 76%-
DFR=32% and OS= 69%
• 12.1% developed temporal lobe necrosis
• 3.6% developed retinopathy

26. ALTERED FRACTIONATION
• NPC9902 Trial
CF arm AF
arm(6#/wk)
CF +CCT
arm
AF+ CCT
arm
Mean RT
dose
69Gy 69Gy 68Gy 69Gy
Overall
incidence
Cumulative 16.7 21.2 27.5 31.8
3 yr acturial
rate
14 22 31 34
Comp with
CF
- P=0.37 P=0.13 P=0.05

27. NPC-9902 TRIAL
Aim: to assess the therapeutic benefit of AF and/or concurrent-adjuvant chemoradiotherapy (CRT).
• 189 patients with locally advanced NPC (T3-T4, N0-1, M0) to four arms:
(i) conventional fractionation (CF) alone,
(ii) AF (six fractions/week) alone,
(iii) CF with concurrent chemotherapy,
(iv) AF with concurrent chemotherapy.
Preliminary Results*: median follow-up of 2.9 years
• AF did not demonstrate significant improvement in event-free survival (EFS) when
compared to CF
(AF vs. CF: HR 0.68, p = .22).
• A significant increase in acute and late toxicity in the AF arm

28. TRIALS FOR ALTERED
FRACTIONATION
• Wang et al, Leung et al, Jen et al show no significant improvement in OS and FFR with AF .
Also, Increased incidence of complications like temporal lobe necrosis and other neurological
toxicities (Teo et al)
• 159 pt randomized in 2 arms
• (38% of cases were T3-4)
• Arm A 2.5 Gy/#QD for 8# f/b 1.6 Gy b.id 32#
• Arm B: 2.5Gy/# QD for 24 #
• Results: prematurely terminated by significant increase in neurological complications
• 5-year local FFR did not improve (89% vs 85%), but there were excessive neurological toxicities
(49% vs 23%)

29. CHEMOTHERAPY
• Highly chemo sensitive
• Currently CRT with or without adjuvant
chemotherapy – standard treatment for locally
advanced stages III to IVB
• Can be given as:
1. Concurrent
2. Neoadjuvant
3. Adjuvant

30. • Langendijk et al- meta-analysis of 10 trials , randomised
NPC pt to conventional RT or CRT
• The authors found an absolute survival benefit of 4% at 5
years
• Overall survival benefit of 20% at 5 yr with CRT
• The results of this study indicate that concomitant
chemotherapy in addition to radiation is probably the
most effective way to improve OS in NPC

31. • The trial was closed early due to a significant overall survival benefit in
favor of CRT (78% vs. 47% at 3 years)
• A 5-year update confirmed progression-free survival (58% vs. 29%) and
overall survival (67% vs. 37%) in favor of CRT
• Wee et al: 221 stage III-IVB patients from Singapore randomized to
receive either RT alone or CRT
• Three-year overall survival for the CRT and RT arms was 85% and 65%,
respectively (p = .006)
• CRT reduced the incidence of distant metastasis by 17% at 2 years (p =
.003)

32. SEQUELAE OF
TREATMENT
The overall complication rate from conventional treatment ranged from
31% to 66%
 Temporal lobe necrosis
 Hearing loss
 Xerostomia
 Neck fibrosis
 Cranial nerve dysfunction
 Endocrine dysfunction
 Soft tissue necrosis
 Osteonecrosis
 Transverse radiation myelitis

33. Thank you

34. RADIATION TECHNIQUE
Patient positioning and
immobilization
Supine position with
head extended (
thermoplastic cast - head
to shoulder)
Shoulder retractor
maybe used to include
the supraclavicular region
within the lateral field
Mouth bite to minimize
the dose to the oral cavity
Enlarged neck nodes
marked with lead wire
before taking simulation

35. 2-D TREATMENT
Lateral parallel opposed portals
Phase I : faciocervical fields ( primary tumor
and upper neck nodes in one volume)
Matching lower anterior field for cervical
lymphatics
Phase II: After 44 Gy the posterior border is
shifted anteriorly to shield spinal cord
• 3 field in ph II –minimize dose to T-M joints
and b/l temporal lobes

36. FIELD BORDERS
• Superior - cover sphenoid sinus and base of skull
• Inferior - above true vocal
• Posterior – tip of spinous processes
• Anterior - 2–3 cm anterior to GTV (and include
pterygoid plates and posterior 1/3 of maxillary sinuses)

38. 3-D CONFORMAL
TREATMENT
• 3D treatment plan is an important technical
advance for improved radiation delivery
• Jen et al: improvement in 3-yr L-FFR and
event free survivalPT. no T4 STAGE
III
STAGE
IV
XEROST
OMIA
3-D 72 86 80 82 69
2-D 108 47 56 33 98

39. Conformal radiotherapy fields

40. IMRT
• The intensity of the radiation beams can be
modulated to deliver a high dose to the tumor
with a superior target volume coverage while
significantly limiting the dose to surrounding
normal tissues
• Biologic enhancement by simultaneous
modulated accelerated radiation therapy (SMART)
aka dose painting

41. • Two different IMRT approach
1. Extended-whole field (EWF) :total target
volume is encompassed in the IMRT plan
2. Split-field (SF) : target volumes superior to
the vocal cords are treated with an IMRT
plan
the lower neck nodes are treated with a
conventional low anterior neck field

42. TUMOR TARGET
VOLUME
• GTV: primary nasopharyngeal tumor, gross
retropharyngeal lymphadenopathy and gross nodal
disease – by clinical, endoscopic and radiologic
examination
• CTV: includes microscopic disease and potential
infiltrative spread
• PTV: CTV including a circumferential margin of
typically 3 to 5mm to all CTVs

43. • HIGH RISK CTV(CTV70) - GTV plus 5 mm to 1 cm margin
• LOW RISK CTV (CTV59.4) - GTV including all potential areas of
microscopic spread of disease
1. entire nasopharynx and its boundaries
2. bilateral upper deep jugular
3. submandibular
4. jugulodigastric
5. midjugular
6. posterior cervical
7. retropharyngeal lymph nodes

45. IMRT series reported excellent results, with local control exceeding 90% at 2-5 years with
CT
Conversely improvement in distant failure is less impressive. Distant relapse rate varies
widely, with 2-year rates ranging from 10% to 15% and 4-year rates as high as 34%.
Hence, more potent systemic therapy is needed for this cancer

46. DOSE CONSTRAINTS: ORGANS AT
RISK:
CRITICAL:
• Brainstem: point < 54Gy
• Spinal cord: point < 45Gy
• Optic chiasma: point < 54Gy
• Optic nerve: point < 54Gy
• Temporal lobes: point< 65Gy and 1% vol <
60Gy
INTERMEDIATE:
• Pituitary: point < 60Gy
• Mandible and TM joint: 1% vol <
70Gy
• Lens: point < 6Gy
• Eyeball: point < 50Gy
LOW RISK:
• Parotid: mean < 26Gy
• Chochlea: mean < 50Gy
• Larynx mean: < 30Gy
• Tongue:1% vol < 60Gy.