This document provides information about nasopharyngeal brachytherapy for the treatment of cancer. It discusses the anatomy of the nasopharynx, indications for brachytherapy including as a boost after external beam radiation or for localized recurrences. Several techniques for nasopharyngeal brachytherapy are described including customized moulds, Rotterdam and Massachusetts General Hospital applicators, and transnasal permanent implants. Typical dose prescriptions and fractionation schedules are provided. Results from studies show brachytherapy improves local control and survival rates compared to external beam radiation alone, especially for early stage tumors.

1. Nasopharyngeal Brachytherapy
Dr. Ashutosh Mukherji
Associate Professor
Department of Radiotherapy,
Regional Cancer Centre, JIPMER

2. INTRODUCTION
• Cancer of the nasopharynx is relatively uncommon in Western
countries (0.5-2/1,00,000/yr), but more frequent in parts of Asia
(30-80/1,00,000/yr) and North Africa (8-12/100,000/yr).
• Mostly Inoperable, spread early to cervical lymph nodes, distant
metastases is fairly well known.
• Main prognosis factors are the local extension of the tumours
(invasion of the base of skull and paralysis of the cranial nerves)
and lymph node metastasis.
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3. ANATOMY…….
3
• The nasopharyngeal cavity
communicates anteriorly with
the nasal cavities through the
choanae and inferiorly with the
oropharynx.
• The sphenoid body limits it
superiorly, the first two
vertebrae posteriorly, and the
soft palate inferiorly.
• The Eustachian tubes open into
its lateral walls, in front of the
fossa of Rosenmüller.

4. INDICATIONS
• Brachytherapy applications of the nasopharynx are restricted to
– Boost for minimal residual local disease after external
irradiation
– Salvage therapy for well-circumscribed and superficial local
recurrences limited to the nasopharyngeal cavity without
involvement of the underlying bone or extending to
oropharynx or nasal cavities
4

5. • Nasopharynx deeply situated and surrounded by bone,
vessels and nerves  usually endocavitary techniques can be
performed.
• CTV thickness should not exceed 10 mm
• Tumours extending into the nasal cavities or the oropharynx
should not be accepted for brachytherapy.
5

6. TARGET VOLUME
• The PTV defined by
endoscopy, CT-Scan and
MRI.
• Most tumours are
situated at the roof of
the nasopharynx.
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In central tumours, the CTV may include both roof and lateral walls.
In well-lateralised tumours, CTV will include the roof and one lateral
wall. In most cases, the depth of PTV does not exceed 10 mm.

7. TECHNIQUES APPLIED
• CUSTOMISED MOULD
• ROTTERDAM
NASOPHARYNGEAL
APPLICATOR
• MASSACHUSETTS GENERAL
HOSPITAL TECHNIQUE
• TRANSNASAL PERMANENT
INTERSTITIAL IMPLANTS
7

8. CUSTOMISED MOULD
TECHNIQUE
• Sagittally oriented plastic tubes are fixed on the surface of a rigid acrylic
applicator, made from an individual impression of the nasopharyngeal
cavity.
• Procedure is therefore performed under neuroleptic analgesia
• Nasal secretions are suctioned and the mucous membranes anaesthetised
with 5% xylocaine spray to avoid gag reflex or pain.
• First rubber catheters are passed through both nostrils and brought out of
the mouth; the oral ends of these are tied to a dummy applicator coated
with silicone paste.
8

9. • This paste coated dummy applicator is pulled into the nasopharynx and
paste forms an impression of the naspharyngeal cavity.
• Then from this impression a negative POP mould is prepared from which
the actual acrylic mould is made with 2-5 mm thick walls.
• Boundaries of the tumour are highlighted in ink and source position that
will provide optimal coverage of the lesion are indicated with sagittal
lines.
• Spacing between sources varies from 10 to 15 mm. In average patients,
the rule for catheter implantation is 2 catheters per wall or 3 catheters for
2 walls or 4 catheters for 3 walls (roof and 2 walls)
9

10. 10

11. ROTTERDAM APPLICATOR
• Is made of soft silicone
• Well tolerated by patient
• Insertion procedure is same as for
customised mould
• The applicator can remain in situ
for the duration of the treatment,
from 2 to 6 days.
• The two silicone tubes, can
accommodate standard 6 French
afterloading catheters.
• The legs of the applicator sort
through the nostrils and are fixed
with a silicone bridge, pushed
against the nasal septum.
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12. 12

13. MASSACHUSETTS GENERAL
HOSPITAL TECHNIQUE
• This technique uses two paediatric endotracheal tubes with inner and
outer diameter of 5 and 6.8 mm, respectively. They can be afterloaded
each with 20-mg radium-equivalent caesium 137 slugs or stepping source
PDR or HDR afterloaders.
• After topical anaesthesia endotracheal tubes are introduced into the
nasopharynx through the nostrils and under fluoroscopic control, the
distal tip of the dummy sources are placed at the free edge of the soft
palate posteriorly and at the posterior wall of the maxillary sinus
anteriorly.
• An inflated balloon, attached to the distal end of the endotracheal tube,
is used to anchor the tubes and to create a distance between the
radiation sources and the nasopharyngeal vault to obtain a better depth
dose.
13

14. TRANSNASAL PERMANENT
INTERSTITIAL IMPLANTS
• Using fibre-optic endoscopy and under direct visualisation, hollow after-
loading needles are introduced into the nasal passages and are advanced
through the posterior choanae, and inserted into the mucosal surface.
• Radioactive I-125 seeds are then introduced submucosally through these
needles, and the needles are withdrawn.
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15. • The dose prescribed to an isodose covering the surface of the
underlying bone, at 5 - 10 mm from the mucosal surface.
• Dose distribution optimized when possible so that the reference
isodose follows the bone surface.
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16. • Brachytherapy used to deliver BOOST dose to a small volume after a full
course of external beam radiation therapy.
• In LDR brachy, the active source is tailored to the nasopharynx proper that
is to the distance between the ‘Node of Rouviere’ (at the level of the C-I
vertebral body) and the pterygoid plates. The Ir-192 source is removed
after a dose of 11 Gy is delivered to the nasopharynx “tumour tissue” (TT)
point.
• For HDR, a boost dose of 9 Gy in 3 fractions of 3 Gy each is delivered with a
minimum interval of 6 hours between fractions prescribed as described in
previous slides.
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17. DOSES PRESCRIBED
• Wang delivered with LDR afterloading intracavitary implant 7 - 12 Gy at 5
mm below the mucosa.
• Levendag et al. deliver after a rest period of 1 - 2 weeks, a boost dose to
the primary site with HDR brachytherapy, with two 3 Gy fractions per day
at 6 hour interval. Total of fractions is 6 (after 60 Gy external beam
irradiation) for T1 - 3 tumours, and 4 (after 70 Gy external beam
irradiation) for T4 tumours.
• For recurrent tumour recurring, 60 Gy is delivered in roughly 6 days with a
LDR technique
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18. 18

19. RESULTS
• Since 1974, at Massachusetts General Hospital, afterloading intracavitary
implant has been carried out as a routine procedure to deliver a dose of 7-
12 Gy as a boost to the nasopharynx for most T1 and T2 and occasionally
T3 lesions
19
5 year survival rates in MGH
in nasopharyngeal cancers

20. RESULTS
• At Rotterdam, in a prospective study of 41 patients treated with 60-70 Gy
external beam radiation therapy and 12 - 18 Gy HDR brachytherapy boost,
the 5-year local relapse free survival rate of T1 - 2 cancer patients (n = 29)
was 96% versus 57% for T4 cancer patients (n = 12) (p = 0.002)
20
5 year actuarial survival rates in MGH in recurrent
nasopharyngeal cancers

21. 21

22. RESULTS
22

23. RESULTS
23

24. RESULTS
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25. RESULTS
• 18–24% of patients with nasopharyngeal carcinoma develop local recurrences
• Brachytherapy is an important modality for treatment of localised small
recurrences.
• Other modalities are:
– Cyberknife RadioSurgery
– SBRT
– IMRT
• The period elapsed before development of local recurrence is a significant
factor influencing disease-free survival times.
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26. Causes of relapse in Ca Nasopharynx
Failure= 192/610 (31%)
Local Failure ONLY= 52%
Distance metastasis=27%
Death= 156/610
Cause of death:
Local Relapse only= 44%
Distance mets= 28%
Local control after relapse improves survival
Sun JA et al, Asian Pacific J 2007

27. Surgery for Rec Nasopharynx
- ONLY few prospective reports
- Skull base/ bone erosion & carotid artery erosion not considered for surgery
- 5-Yr OS: 40-60%
- 20% palatal fistula

28. 28

29. Liu et al. Radiation Oncology 2013
SBRT: persistent Nasopharyngeal Ca

30. -No difference in maximum spinal cord dose and mean parotid doses between
HDR & CK boost plans; In IMRT plan, higher ipsi-lateral parotid dose
Comparison of three plans (Dose: 24
Gy/6#)
IMRT boost HDR boost CK boost
Spinal cord Dmax
(Gy)
7.4 1.2 1.5
Ipsi-lateral parotid
Mean dose
(Gy)
8.3 3.1 2.1
Conta-lateral parotid
Mean dose
(Gy)
3.7 1.4 1.7
(n=11) Dutta et al; CK Society meeting San Francisco 2010

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• Study from Hong Kong
• 34 patients with locally persistent NPC who were treated during 1992–2000
with HDR intracavitary brachytherapy were analyzed retrospectively. All
patients had T2b disease at initial diagnosis.
• An improvement in the 5-year actuarial local failure-free survival rate
(brachytherapy group vs. ERT group: 96.9% vs. 81.5%; P 0.024), the disease
specific survival rate (84.5% vs. 68.1%; P 0.021), and the overall survival rate
(78.3% vs. 63.1%; P 0.034) was seen in the group with locally persistent NPC
salvaged with brachytherapy.

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