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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
A
C
Figure 6.3A-C
posterior border is placed behind the spinous processes or
farther back to cover an extended scar.
• Inferior border: just superior to the arytenoids.
An anterior appositional eld is used to treat the mid- and
lower neck nodes. Field borders are indicated in the section
“General Principles.”
To deliver the boost dose to the primary tumor and upper
neck nodes, the size of lateral elds is reduced to encompass
the known disease locations. It is also prudent to cover the
root of tongue or deep oor of mouth muscles to the insertion
at the hyoid bone in the boost volume since recurrence tends
to occur in these regions even for relatively super cial tumors.
To boost the upper neck without the primary site, a lateral appositional electron eld is used. To deliver the boost
to the mid or lower neck, a lateral appositional electron eld
or glancing photon elds are used.
Dose
• A dose of 60 Gy in 30 fractions is administered to areas
th high-risk features, that is, close or microscopically
wi
B
positive margins, perineural extension, vascular invasion,
positive nodes, or extranodal extension. An additional
boost dose of 6 Gy in three fractions may be given when
indicated, such as when multiple adverse features are present or when the interval between surgery and radiation is
much longer than 6 weeks.
• A dose of 56 Gy in 28 fractions to the surgical bed.
• A dose of 50 Gy of elective irradiation in 25 fractions to
ected regions.
undiss
Intensity-Modulated Radiation Therapy
Conformal radiotherapy can eliminate sequential portal
cone-down because the dose gradient to the tumor bed and to
regions at risk for harboring microscopic disease is achieved
by varying the fraction size. When using intensity-modulated
radiation therapy (IMRT) in the postoperative setting, treatment is given in 30 fractions as illustrated in Case Studies 6-4
to 6-8. Smaller target volumes considered to be at extra-high
risk, o en determined in collaboration with the surgeon and
based on pathologic ndings, receive 64 to 66 Gy.
Chapter 6 Oral Cavity
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Case
Study
6-4
3 positive nodes in levels II and III without ECE. He was treated
with postoperative radiation. e tumor bed, consisting of the
le lateral tongue and le upper neck, with margin was identi ed as CTVHD (60 Gy). e undissected right neck and right
hemitongue was contoured as CTVED (54 Gy).
Figure 6.4 shows CTVHD (red) and CTVED (blue)
paired with isodose distributions at the level of the tongue
A 47-year-old man presented with biopsy-proven
SCC of the le oral tongue. He underwent a partial
glossectomy with selective le neck dissection.
e primary tumor was 1.2 cm in size and had
negative margins. e neck dissection yielded
(Fig.6.4A,B) and upper neck (Fig. 6.4C,D). Figure 6.4E,F:
show isodose distributions on a sagittal view through the
midtongue and a coronal view, respectively. An intraoral
stent opens the mouth and separates the palate from the
tongue (Fig. 6.4E). e isocenter was placed just above the
thyroid notch (Fig 6.4F). IMRT was delivered to elds above
the isocenter. Level III and IV nodes were treated with an
anterior beam with a larynx block to 40 Gy and with a full
midline block to 50 Gy. Right level III was boosted to a total
of 60Gy with glancing photon beams. e patient remains
without disease 5 years later.
A
C
Figure 6.4A-D
B
D
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Part 2 Site-Specifi c Indications and Techniques
E
Figure 6.4E,F
Case
Study
6-5
glossectomy and le selective neck dissection. Histologic
examination revealed a 2.5-cm carcinoma with negative margins. e neck dissection revealed only 1 positive
A 78-year-old man presented with an anterior oral tongue tumor and a palpable le
level IB node, also detected on the staging CT
scan (Fig. 6.5A). Biopsy of the primary tumor
was positive for SCC. He underwent a partial
F
lymph node, 2.5 cm in size consistent with the clinical ndings. ere was ECE. He was treated with postoperative
IMRT. Concurrent chemotherapy was indicated but not
given due to concern about tolerance secondary to overall
performance status and age.
e tumor bed, consisting of the anterior tongue and
le upper neck, with margin was identi ed as CTVHD (60
Gy—orange). Dissected ipsilateral level IIb was contoured
A B
Figure 6.5A,B
Chapter 6 Oral Cavity
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as CTVID (57 Gy—blue). e undissected right neck and
an additional 0.5 to 1 cm on the tongue were identi ed as
CTVED (54 Gy—yellow). e region of the positive node
at le level IB was delineated to give a simultaneous integrated boost to a total dose of 65 Gy (red). Representative
axial slices of the contours and isodose distribution from
the level of the midtongue to inferior level II of the neck
are shown in Figure6.5B–D. e isocenter was placed just
above the thyroid notch. IMRT was delivered to elds above
the isocenter. Level III and IV nodes were treated with an
anterior beam with a larynx block to 40 Gy and with a full
midline block to 50 Gy. Right level III was boosted to 60 Gy
with glancing photon beams. Also shown are isodose distributions through the isocenter in sagittal (Fig. 6.5E) and
coronal (Fig. 6.5F) view and through the midtongue and
level IB in coronal view (Fig. 6.5G). e patient remains
without disease 3 years later.
C
E
Figure 6.5C-F
D
F
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Part 2 Site-Specifi c Indications and Techniques
G
Figure 6.5G
Case
Study
6-6
hyoid neck dissections. Histologic examination revealed
a 1.8-cm SCC with negative margins. e neck dissection
A 66-year-old man presented with a 2.5-cm
anterior oor of mouth tumor with extension onto the ventral tongue without palpable
lymph adenopathy (T2 N0). He underwent a
partial glossectomy and bilateral supraomo-
specimen contained 5 positive nodes, 2 in le level III, 2 in
right level I, and 1 in right level II compartments. ere was
no ECE. He received postoperative radiation using IMRT
to the primary tumor bed and upper neck and a matching
anterior portal for lower neck as described Case Study 6.7.
Since the positive nodes were scattered through the
neck, and were not well identi ed on preoperative imaging,
A
Figure 6.6A,B
B
Chapter 6 Oral Cavity
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69
bilateral level I and II nodes, the oor of mouth and anterior tongue, and the musculature that inserts onto the hyoid
bone were de ned as CTVED (60 Gy).
Figure 6.6 shows target volumes on 2 axial images
at the levels of the mandible (Fig. 6.6A) and upper neck
(Fig.6.6B) and sagittal image (Fig. 6.6C) along with isodose
distributions on axial (Fig. 6.6D), sagittal (Fig. 6.6E), and
coronal (Fig. 6.6F) views. e patient is without disease
2years later.
C
E
Figure 6.6C-F
D
F
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Part 2 Site-Specifi c Indications and Techniques
Case
Study
6-7
underwent surgical resection, including an anterior mandibulectomy, and bilateral supraomohyoid neck dissections
followed by reconstruction with a bula free ap. Histologic
examination revealed SCC, poorly di erentiated, invading
the bone. ere was carcinoma in situ at the tongue margin.
He received postoperative IMRT to the primary tumor
bed and upper neck. e tumor bed, consisting of the
oor of mouth, resected right mandibular bed and anterior tongue with margin was identi ed as CTVHD (60 Gy).
A 67-year-old man who presented with oral
pain was found to have a tumor of the anterior
oor of mouth that spilled over the anterior
gingiva. CT scan revealed a lesion in the oor
of mouth eroding the mandible (Fig. 6.7A). He
e dissected necks that did not harbor disease were
contoured as CTVID (57 Gy).
Figures 6.7B-D show isodose distributions on axial
images at the level of the reconstructed mandible and ap
(Fig. 6.7B) and upper neck (Fig. 6.7C), and a sagittal view
through midplane (Fig. 6.7D).
e IMRT beams were matched at an isocenter, placed
above the thyroid notch, to an anterior portal for treating
the lower nodal stations. e initial anterior beam had a
larynx block and was treated to 40 Gy (Fig. 6.7E). A full
midline block was added and the elds treated to 50 Gy
(Fig. 6.7F). Bilateral level III, part of the operative bed,
was boosted to 56 Gy with an anterior beam (Fig. 6.7G).
e patient remains without disease 3 years later.
A
C
Figure 6.7A-D
B
D
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E
G
Figure 6.7E-G
Case
Study
6-8
sive primary tumor eroding the le mandible as shown
in Figure 6.8A (green arrows). Treatment began with a
wide local resection, including le mandibulectomy, and
le neck dissection followed by reconstruction using an
osteocutaneous free- bular ap and skin gra . e bula
replaced the horizontal ramus whereas the so tissue lled
in the space of the resected le ascending ramus. Histologic examination revealed a 2.9-cm poorly di erentiated SCC with bone invasion, but margins were negative.
None of 28nodes were positive for disease. Stage pT4 N0.
He was treated with adjuvant ipsilateral IMRT because
the tumor was well lateralized and there was no nodal
involvement. Figure 6.8B shows a coronal view through
A 49-year-old man presented to his dentist
with le -sided oral pain and was found to have
a lesion of the le alveolar ridge. A biopsy was
positive for SCC.
A diagnostic CT scan revealed an inva-
F
the right ascending ramus of the mandible with CTVHD
(red) and CTVID (blue) outlined. CTVHD encompasses the
preoperative tumor volume with generous margins, and
CTVID covers the operative bed including generous coverage of the masticator space. e absence of the le ascending mandibular ramus can be appreciated on this coronal
view. Figure6.8C–F: show axial isodose distributions along
with CTV
rior maxilla and masticator space, the superior aspect of
the horizontal ramus of the mandible, the bula gra and
epicenter of the original tumor, and level II nodal region,
respectively. Note that CTVHD includes 1 cm of the residual
mandible across midline and the upper neck to encompass
so tissues of the inferior–lateral portion of the oor of
mouth musculature and tissues inferior to the angle of the
mandible. e le level III and IV nodes were treated with a
matching anterior beam to a dose of 50 Gy in 25 fractions. e
patient had no evidence of disease 2 years a er treatment.
(red) and CTVID (blue) at the level of the infe-
HD
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Part 2 Site-Specifi c Indications and Techniques
A
C
B
D
E
Figure 6.8A-F
F
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73
e patient is immobilized in a supine position, with an
extended thermoplastic mask covering head and shoulder.
in-cut computed tomography (CT) images are obtained
in treatment position, and target volumes are outlined for
dosimetric planning.
Virtual Gross Target Volume
ere is no actual GT V a er complete surgical tumor resection.
However, it can be useful to formulate a virtual GTV (vGTV)
to facilitate target volume de nition. e vGTV is a 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.
• CTV1 delineates volumes to receive the highest dose (there-
fore also refe rred to a s CT VHD). is includes the primary and
nodal vGTVs with 1-cm margins. For larger primary tumors,
CTVHD o en covers the entire tongue and oor of mouth.
• CTV2 delineates volumes to receive an intermediate dose
(therefore also referred to as CTVID). For the primary
tumor bed, CTVID encompasses the remaining operative bed and/or a 0.5- to 1-cm additional margin beyond
CTVHD. For the neck, it covers the dissected neck not harboring involved nodes.
• CTV3 delineates volumes to receive an elective dose for
subclinical disease (therefore also referred to as CTVED).
In the N0 neck, nodal levels I to IV are included in CTVED
When microscopic perineural invasion is present, CTVED
includes the lingual nerve and/or inferior alveolar nerves
to approximately the distal end of the mandibular nerve
(V3) either ipsilaterally or, for tumors extending to or
crossing midline, bilaterally. For extensive perineural
extension (involvement of large nerve or presence of clinical signs), CTVED includes the proximal V3 up to the skull
base or even the trigeminal ganglion.
e isocenter is generally placed above the arytenoids.
Level III and IV nodes are preferentially treated with a
matching anterior beam similar to conventional techniques.
40 Gy, and then a full midline block can be used up to 50 Gy.
e dissected uninvolved nodal levels are boosted to 56 Gy,
and an additional 4 Gy is added if these lower neck nodes
harbored disease.
Some patients have extensive reconstruction with large
aps. If the bulky aps extend at the level of the larynx or
more inferiorly, matching the low neck beam to the IMRT
elds may be more complicated, and it may be di cult to
get the appropriate dose to the neck tissues at risk deep to
the aps. In these cases, treating all the targets with a single
IMRT plan may be more e ective, though additional attention should be paid to delineating the larynx and esophagus as avoidance structures for minimizing the dose to these
organs.
Timing of Postoperative Radiotherapy
It is desirable to commence postoperative radiotherapy as
soon as possible a er healing of surgical wounds. With good
communication between surgical, radiation, and dental
oncologists, simulation can usually take place 3 to 4 weeks
a er surgery, and radiotherapy can start within a week in
most patients. When delayed wound healing postpones
commencement of postoperative radiation to beyond 5 to
6 weeks, we administer accelerated fractionation, such as
concomitant boost, by delivering twice-a-day irradiations for
5 treatment days, either once a week or toward the end of the
radiation course, to reduce the potential hazard of prolonged
cumulative treatment time.
Primary Radiotherapy
Target Volume
Initial Target Volume
• A well-di erentiated, super cial lesion of 1 cm or less with
no palpable lymphadenopathy (T1 N0): primary tumor
with 2-cm margins.
• Floor of mouth (mostly anterior) lesion of 1- to 4-cm
maximal diameter without palpable lymphadenopathy
(T1 to T2 N0): primary tumor with at least 2-cm margins
and level I (submental and submandibular) and Level II
nodes.
• Oral tongue tumor >1 cm thick with no palpable lymphad-
enopathy: primary tumor with at least 2-cm margins and
level I to IV nodes.
• Presence of lymphadenopathy (N+) at diagnosis calls for
irradiation of the entire cervical nodal basins.
A boost volume encompasses the primary tumor (1- to 2-cm
margins) and involves lymph nodes.
Setup and Field Arrangement
For small T1 N0 lesions, the entire treatment is given with an
intraoral cone or by implant (if the risk for anesthesia is low).
For all other stages, treatment is given with external
beam irradiation by conventional technique or IMRT as
described above for postoperative radiotherapy. Use of stent,
insertion of a seed at the anterior border of the tumor, and
marking the oral commissures before obtaining simulation
images facilitates shaping of the target volumes.
e boost dose to the primary tumor is preferably delivered by interstitial implant. If the patient cannot undergo
anesthesia, boost dose is given with orthovoltage x-rays
through an intraoral cone when accessible; in this case,
the boost is delivered before the start of the external beam
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