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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4505_Библиотеки_им_академика_М_И_Перельмана
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Part 2 Site-Specifi c Indications and Techniques
Case
Study
12-1
the inferior maxillary sinus, with extension to both the posterior wall and the premaxillary so tissue. She underwent
A 77-year-old woman presented with tingling
of the le anterior maxillary gingiva. Physical examination showed a mass in the gingiva
extending to the hard palate. Imaging studies
revealed that the epicenter of the mass was in
an infrastructure maxillectomy. Histologic examination
revealed grade 2 mucoepidermoid carcinoma.
Figure 12.1 illustrated postoperative radiation delivered
using anterior (Fig. 12.1A) and le lateral (Fig. 12.1B), wedgedpair, portals with 45-degree wedges. e total dose was 60 Gy,
with a serial reduction made at 54 Gy. An isodose distribution
through the resected sinus is shown in Figure 12C.
A
C
Figure 12.1A-C
B
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205
Case
Study
12-2
and postoperative radiation.
Figure 12.2 shows details of radiation treatment
delivered through an anterior (Fig. 12.2A) and two
A 46-year-old woman was found to have a
right nasal polyp, biopsy of which revealed
neuroblastoma. Imaging revealed the bulk of
tumor in the medial wall of the right maxillary
sinus. She underwent a medial maxillectomy
lateral–opposed portals (Fig. 12.2B) with 6 MV photons,
with 60-degree wedges being used on the lateral elds
with the heels oriented anterior. e loading of anterior
to lateral–lateral was 1:0.07:0.07. e lateral elds were
reduced a er 40 Gy, and the total dose was 56 Gy speci ed at the 95% line. Representative isodose distributions
through the maxillary sinus and between the orbits are
shown in Figure12.2C,D.
A
C
Figure 12.2A-D
B
D
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Part 2 Site-Specifi c Indications and Techniques
Case
Study
12-3
a small focus of carcinoma within inverted papilloma. Eight
months a er the second surgery, this patient was referred to
the M.D. Anderson Cancer Center for treatment of a large
recurrence located in the right maxillary sinus, orbit, and
infratemporal fossa. He underwent resection of this tumor with
orbital exenteration. Histologic examination revealed inverted
papilloma with multiple foci of squamous cell carcinoma.
e margins of resection contained papilloma but were
free of invasive carcinoma. He received postoperative radiotherapy as shown in Figure 12.3. e surgical bed was treated
A 67-year-old man underwent a removal of a
polyp of the right nasal cavity. Histologic examination showed an inverted papilloma. ree
years later, he underwent a second polypectomy
for recurrence. Histologic examination revealed
with an anterior (Fig. 12.3A) and right (Fig. 12.3B) and le
lateral elds loaded 1:0.15:0.15, respectively. A stent was used
to depress the tongue. A water- lled balloon was placed in
the surgical defect. e surgical scar, lateral orbital canthi,
and oral commissures are marked. e initial target volume
received a dose of 50 Gy in 25 fractions, speci ed at the isocenter. Subsequently, the elds were reduced to administer
a boost dose of 10 Gy in 5 fractions to the tumor bed. A CT
scan was obtained for treatment planning, which showed
good lling of the surgical defect with the water- lled balloon
(Fig. 12.3C,D). is patient did well until 22 months later
when a pedunculated lesion was noted in the right ethmoid
remnant along with a rm area in the oor of the maxillary
defect. Biopsy of both lesions revealed di usely in ltrating
inverting papilloma with focal squamous cell carcinomas.
Figure 12.3A-D
Chapter 12 Paranasal Sinuses
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207
(e.g., a er craniofacial resection), a wire is placed on the
premaxillary skin to indicate the slope of this structure. In
addition, it is helpful to mark the position of the medial and
inferior limbus with the eyes gazing forward for the purpose of corneal shielding. e location and size of the tumor
determine the appropriate portal borders and arrangement.
For tumors of the infrastructure with no extension
into the orbit or ethmoids (uncommon), anterior and ipsilateral wedge-pair (usually 45-degree wedges) photon elds
are used (Case Study 12-1). e use of the “half-beam” technique (i.e., placing the isocenter at the level of the orbital
oor and shielding of the upper half of the elds) prevents
exposure of the contralateral eye by beam divergence.
Anterior portal borders:
• Superior: j
• Lateral: 1 cm beyond the lateral wall of the maxillary sinus
(or falling-o when there is tumor extension into the facial
so tissues).
• Medial: 1 to 2 cm across midline.
• Inferior: 1 cm below the oor of the maxillary sinus or
below the surgical bed.
Lateral portal borders:
• Superior and inferior: s
• Anterior: in front of the anterior wall.
• Posterior: behind the pterygoid plates or more posteriorly
depending on the extent of the contiguous tumor spread.
For tumors of the infrastructure spreading across midline
through the hard palate, lateral–opposed photon elds are
preferred. e use of the “half-beam” technique (i.e., placing the isocenter at the level of the orbital oor and shielding of the upper half of the elds) prevents exposure of the
contralateral eye by beam divergence. e portal borders are
similar to the lateral eld described previously.
a three- eld technique is used (Case Studies 12-2 and 12-3).
An a
Loading varies from 1:0.15:0.15 to 1:0.07:0.07 depending on
the tumor location and photon energy. e lateral elds have
60-degree wedges and can have a slight posterior tilt.
Anterior portal borders:
• Superior: a
and, in the absence of orbital invasion, at the lower edge
of the cornea to cover the orbital oor. When the orbit is
involved, an attempt is made to shield the lacrimal gland
whenever possible to avoid occurrence of dry, painful eye.
Tumor extension into the frontal sinus or cranial fossa
calls for a more generous superior coverage.
• Inferior: 1 cm below the oor of the maxillary sinus or
below the surgical bed.
• Medial: 1 to 2 cm, or farther, across midline to cover the
contralateral ethmoidal extension.
ust above the oor of the orbit but below the cornea.
ame as the anterior portal.
For tumors involving the suprastructure or ethmoids,
nterior portal is combined with right and le lateral elds.
bove the crista galli to cover the ethmoids
• Lateral: depends on the tumor extent (1 cm beyond lateral
orbital wall when this structure is intact or falling o
when there is tumor extension into facial so tissues or
infratemporal fossa).
Lateral portal borders:
• Superior: f
cranial fossa.
• Inferior: corresponds to that of anterior portal.
• Anterior: behind the lateral bony canthus parallel to the
slope of the face as marked by the wire.
• Posterior: behind the pterygoid plates or more posteriorly,
depending on the extent of the contiguous tumor spread
and the surgery.
For boost volume, the portal size is reduced to encompass
the tumor bed and to exclude as much optic pathway as possible. e contralateral optic nerve and chiasm are excluded
from the eld a er a dose of 54 Gy in 27 fractions. Sometimes, this requires two eld reductions (i.e., a er 50 Gy and
54 Gy, respectively). When the lesion abuts these structures,
the bene ts and risks of delivering a maximum dose of 60 Gy
in 30 fractions, which carries a 5% to 10% risk of blindness
resulting from nerve injury, are discussed with the patient.
For treatment of the neck nodes, ipsilateral upper neck
irradiation is given to patients with squamous cell or undifferentiated carcinomas, stages T2 to T4 N0. is is accomplished through a lateral appositional electron eld.
• Superior border: slo
the mandible anteriorly to match the inferior border of the
primary portal posteriorly. is portal matching creates
a small triangle over the cheek, which is irradiated with
an abutting triangular, appositional electron eld (6 MeV)
when there is tumor extension into facial so tissues.
• Anterior border: just behind the oral commissures.
• Posterior border: at the mastoid process.
• Inferior border: at the thyroid notch (above the arytenoids).
Bilateral neck treatment is indicated in patients presenting with palpable node(s). Proper eld-matching technique
should be selected in this setting to minimize dose heterogeneity, particularly to prevent overdosing in the depth
by beam divergence. is can be accomplished by treating both the primary tumor bed and the upper neck with
half-beam technique (shielding the caudal half of maxillary
elds andthe cephalad half of neck elds) to eliminate divergence and thereby prevent beam overlap. e central axis of
the primary tumor portals and that of the opposed–lateral
upper neck elds are placed at the axial plane of the inferior
portal border of the maxillary elds (i.e., usually 1 cm below
the oor of the maxillary sinus). It is prudent to move the
junction line between the primary and neck elds during
the course of treatment. e mid and lower neck is irradiated with an anterior appositional photon eld matched to
ollows the contour of the oor of the anterior
ping up from the horizontal ramus of
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Part 2 Site-Specifi c Indications and Techniques
the inferior border of opposed–lateral upper neck elds (see
“General Principles”).
e portal borders of the maxillary elds are as de ned
previously. e borders of the upper neck elds are determined by the extent of the nodal disease. If the initial lateral
elds are on the spinal cord, portal reduction is made a er
approximately 45 Gy. e posterior cervical areas are then
irradiated to the desired dose with abutting electron elds.
Intensity-Modulated Radiation Therapy Planning
e complex anatomy of the paranasal sinuses makes it
appealing to use high-precision conformal radiotherapy for
the treatment of sinonasal tumors to reduce normal tissue
toxicity without compromising the dose to the tumor bed.
IMRT generally yields better dose distribution for these
tumors (see Case Studies 12-4 and 12-5).
e patient is immobilized in a supine position with an
extended head and shoulder thermoplastic mask. in-cut
computed tomography (CT) scans are obtained in treatment
Case
Study
12-4
strated a mass in the inferior aspect of the right maxillary sinus. e mass (green arrows) can be seen on axial
(Fig.12.4A) and coronal views (Fig. 12.4B). She underwent
an infrastructure maxillectomy. Histologic examination
revealed SCC with bone invasion (stage pT4 cN0).
Postoperative IMRT was administered in 30 fractions.
CTVHD (red colorwash), CTVID (blue), and CTVED (yellow)
A 60-year-old woman presented with a loose
right maxillary tooth. A biopsy taken from the
tissue adjacent to the tooth was positive for
squamous cell cancer (SCC).
A CT scan was obtained and demon-
position. e clinical target volume (CTV) and planning
target volume are outlined for dosimetric planning.
Virtual Gross Target Volume
ere is no actual gross target volume (GTV) a er a complete surgical tumor resection. However, it can be useful
to formulate a virtual GTV (vGTV) to facilitate target volume de nition. e vGTV is the best approximation of the
tissues having high likelihood of harboring microscopic
tumor reconstructed based on ndings of preoperative clinical examination, imaging studies, and surgical–pathologic
assessment. Bulky aps can cause substantial distortions in
the tumor bed and should, therefore, be taken into account
in reconstructing the vGTV.
Clinical Target Volumes
ree CTVs are generally delineated.
• CTVHD delineates volumes to receive the highest dose. is
includes the primary and nodal vGTVs with 1-cm margins.
were prescribed 60 Gy, 57 Gy, and 54 Gy, respectively.
CTVHD encompassed the right maxillary sinus and medial
aspect of the resected palate, CTVID an additional margin
on the operative bed, and CTVED the undissected, ipsilateral lymphatics considered at risk including the right facial
nodes and right level I and II nodes. Figure 12.4 displays
contours and isodose distribution on axial views at the level
of the mid sinus (Fig. 12.4C), inferior sinus (Fig. 12.4D),
facial and superior level II nodes (Fig. 12.4E), and mid level
I and II nodes (Fig. 12.4F). e patient was in an excellent
general condition and had no evidence of disease at the last
follow-up.
A
Figure 12.4A,B
B
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209
C
E
Figure 12.4C-F
Case
Study
12-5
He underwent a total maxillectomy. Histologic examination revealed a 5-cm squamous cell carcinoma of the sinus
invading the hard palate. He was treated with postoperative
IMRT, delivered in 30 fractions.
A vGTV (green colorwash) was de ned based on the clin-
ical, surgical, and pathologic ndings. CTVHD (orange), CTVID
A 58-year-old man presented with a right
facial mass and oral pain.
A CT scan showed a large mass in the right
maxillary sinus invading the right buccal space
and so tissues of the cheek (Fig. 12.5A,B).
D
F
(aqua), and CTVED (yellow) were prescribed 60 Gy, 57 Gy, and
54 Gy, respectively. Axial views at the level of the ethmoids
(Fig. 12.5C), superior sinus and oor of the orbit (Fig. 12.5D),
mid maxillary sinus (Fig. 12.5E), and upper neck (Fig. 12.5F)
are shown with target contours in colorwash and isodose distribution. Matched coronal slice through the sinus with and
without contours are shown in Figures 12.5G,H. Figures 12.5I
and J show a coronal isodose distribution (Fig.12.5I) posterior to the sinus and a sagittal isodose distribution (Fig.12.5J)
through the mid right orbit and resected sinus. e patient
had no evidence of disease 2years posttreatment.
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A
C
B
D
E
Figure 12.5A-F
F
G H
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Chapter 12 Paranasal Sinuses
211
I
e entire sinus is included in this volume. Medially, the
ipsilateral nasal cavity to the septum is included. Generous
coverage is given posteriorly into the residual masticator
space and pterygomaxillary tissues as this is a frequent site
of recurrence. e lateral edge includes the masticator space.
In patients with partial palate resection, CTV
least 1 cm of the remaining palate. If the oor of the orbit was
involved, CTVHD needs to cover the inferior orbital tissues as
a minimum. For disease extension beyond the sinus, CTVHD
should cover these tissues with a 0.5- to 1-cm margin.
• CTVID delineates volumes to receive an intermediate
dose. For the primary tumor bed, CTVID encompasses a
0.5- to 1-cm additional margin beyond CTVHD. For anterior tumors in particular, the skin, if not covered by CTVHD,
includes at
HD
J
will need to be included, and bolus may be required. For
the neck, CTVID covers the dissected nodal region not
harboring involved nodes.
• CTVED delineates volumes to receive an elective dose for
subclinical disease. When microscopic perineural invasion
is present, the maxillary nerve up to foramen rotundum, if
not covered in higher dose CTVs, should be encompassed
in CTVED. For extensive perineural extension (involvement of large nerve or presence of clinical signs), CTVED
includes the proximal V2 up to the trigeminal ganglion.
In squamous cell or undi erentiated carcinomas without
clinical nodal involvement, CTVED encompasses the ipsilateral nodal levels I and II and buccal and facial nodes. For
tumors crossing midline, CTVED covers bilateral nodes.
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e isocenter is generally placed in the center of the treated
volume. In the node positive patient, the isocenter can be
placed at a level just above the arytenoids. Nodal levels III
and IV are preferentially treated with a matching anterior
beam similar to convention techniques. e dissected uninvolved nodal levels are boosted to 56 Gy, and an additional
4Gy is added if these lower neck nodes harbored disease.
Dose
Primary tumor bed: 50 Gy in 25 fractions to the initial target
volume plus 10 Gy in 5 fractions (negative margins) to 16 Gy
in 8 fractions (positive margins) to the boost volume.
Elective nodal irradiation: 50 Gy in 25 fractions.
Involved nodal regions (particularly in the presence of
extracapsular nodal disease): 60 to 66 Gy in 30 to 33 fractions.
IMRT: 60 Gy to the primary tumor bed and 54 to 57 Gy
to the surgical bed in 30 fractions. In case of close or positive margins, a small volume within CTVHD receives 66 Gy in
30fractions (2.2 Gy per fraction). erefore, the fraction size
varies from 2.0 to 2.2 Gy to the tumor bed and from 1.8 to
1.9Gy to the surgical bed.
Instructing the patients to open the eye during irradiation to take advantage of the photon-dose buildup characteristics can minimize the dose to the cornea. e dose to the
macula, optic nerve, and chiasm is limited to 54 Gy or less
whenever possible to minimize the risk of blindness.
Dose Specifi cation
For the primary tumor bed, speci cation is at an isodose line
with dose heterogeneity of no more than ±5%. A planning
CT scan is obtained, and loading, wedges, and eld margins are adjusted when necessary or for conformal radiation
planning.
Primary Radiotherapy
e radiation techniques are the same as those in the postoperative radiotherapy setting. Portal borders are determined
by radiologically demonstrable tumor extent. With conventional technique, the prescribed dose is 50 Gy in 25fractions to the initial target volume plus 16 to 20 Gy in 8 to
10 fractions to the boost volume.
Intensity-Modulated Radiation Therapy Planning
e complexity of the anatomy and the proximity to the
brain and optic structures makes tumors located in these
areas well suited for IMRT, which has become our preferred
technique. e patient is immobilized in a supine position,
with an extended head and shoulder thermoplastic mask.
in-cut CT scans are obtained in treatment position. e
target volumes are outlined for dosimetric planning
Case Study 12-6).
Gross Target Volume
GTV represents all areas determined from clinical examination and imaging studies to contain gross disease.
Clinical Target Volume
ree CTVs are generally delineated.
• CTVHD delineates volumes to receive the highest dose.
is includes the primary and nodal GTVs with 0.5- to
1-cm margins.
• CTVID delineates volumes to receive an intermediate dose,
which includes a 0.5- to 1-cm margin around CTVHD.
In the node positive neck, CTVID covers the involved
nodal bed outside CTVHD and an additional 1 to 2 cm in
cranial–caudal directions.
• CTVED delineates volumes to receive an elective dose for sub-
clinical disease. If not already included in higher dose targets
(rare), CTVED should cover the entire sinus and the oor
of the orbit, ethmoid sinuses, masticator space, and pterygomaxillary tissues. If perineural invasion is present, CTVED
includes V2 as per the guidelines described in the postoperative setting. In squamous cell or undi erentiated carcinoma
without clinical nodal involvement, CTVED encompasses
ipsilateral facial, buccal, and levels I and II nodes. If the tumor
crosses midline, bilateral nodal irradiation is recommended.
If level I or II node is involved, CTVED covers levelsIII and IV
regions. Alternatively, levels III and IV regions can be irradiated with a separate matched anterior beam with an isocenter
placed above the thyroid cartilage.
A dose of 70 Gy is prescribed to CTV
CTVID, and 56 to 57 Gy to CTVED. e nodal volumes are
, 60 to 63 Gy to
HD
(see
Case
Study
12-6
toid carcinoma. Magnetic resonance imaging (MRI) revealed
the maxillary sinus mass with perineural invasion through
foramen rotundum extending to the cavernous sinus. He was
treated with concurrent cisplatin (100 mg/m2 given every
3weeks) and radiation. IMRT was used given the tumor shape.
A dose of 70 Gy in 35 fractions was prescribed to CTV
66 Gy isodose line encompassed the entire volume at risk.
A 46-year-old man presented with maxillary
tooth pain and numbness of the le palate and
cheek. A le maxillary sinus mass was found, and
a Caldwell-Luc procedure was performed. Histologic examination of the tissue revealed sarcoma-
HD
. e
Figure 12.6 shows axial (Fig. 12.6A), coronal
(Fig.12.6B), and sagittal isodose (Fig. 12.6C) distributions
through the sinus. e le upper neck received 50 Gy in
25 fractions through a matching 12-MeV electron eld.
Postradiation imaging revealed residual abnormality in the
maxillary sinus. A maxillectomy was performed revealing squamous cell carcinoma with extensive degenerative
changes. e nerve specimens did not contain tumor. ree
months a er surgery, osteoradionecrosis of the anterior
maxilla and palate developed. He was treated with hyperbaric oxygen and sequestrectomy. e patient remains
without evidence of disease 2 years a er treatment.
Chapter 12 Paranasal Sinuses
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A
C
Figure 12.6A-C
the same as in the postoperative setting. e fraction number
ranges from 33 to 35 and is usually determined by the volume of central nervous system (CNS) adjacent to the target
encompassed in the high-dose regions. It is desirable to keep
the fraction size to the CNS below 2 Gy.
ETHMOID SINUSES
Treatment Strategy
Till recently, most patients have been treated with surgery and postoperative radiotherapy. A combination of
chemotherapy and radiation has been used in select cases for
organ preservation (see Case Study 12-7).
B
Postoperative Radiotherapy
e radiation techniques are the same as those for carcinoma of the suprastructure of the maxillary sinus (see Case
Study 12-8). In the event of a craniofacial resection, no
attempt is made to cover the incision site along the scalp.
e total dose usually does not exceed 54 Gy without a
detailed consent from the patient because it is extremely di cult to exclude optic nerves from the target volume due to the
proximity. IMRT o en provides better dose distribution in this
setting and is the preferred technique (see Case Study12-9).
e dose to the chiasm may exceed 54 Gy if necessary for target coverage, again, provided a detailed consent is obtained
from the patient. e fundamentals for target de nition are
similar to those applied for tumors of the suprastructure.
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