Radiotherapy
Planning for
Esophageal Cancers
Parag Sanghvi, MD, MSPH
9/12/07
Esophageal Cancer Tumor Board
Part 1
Radiation for Esophageal Cancers
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Definitive
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Cervical Esophagus – 60 – 66 Gy
Thoracic/GE junction – 50 -54 Gy
Dose escalation has not shown improved survival in
definitive CRT for esophageal cancers (INT 0123)
Neoadjuvant
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T3 or higher
N+
45 – 50 Gy
Radiation for Esophageal Cancers
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Post – Operative
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Rare; difficult to tolerate
45 Gy
Palliative
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Dysphagia
30 – 35 Gy
Treatment Planning
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Simulation
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Immobilization
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Isocenter set-up
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Vac Lok
2D vs. 3D
3D – Treatment planning CT
Tattoos
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Daily Set-up
Treatment Planning
2D Era – RTOG 8501
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RTOG 8501 compared CRT (50 Gy) to RT alone (64Gy)
Mid/Lower Esophageal Cancers
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Initial Field was AP/PA to 30 Gy in CMT arm
Extended from SCV region to GE junction
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Boost field was tumor + 5 cm sup/inf with a 3 field or opposed
obliques
Advantages
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Omitted SCV nodes in lower esophageal tumors
AP/PA limited lung dose
Replacing PA with oblique fields limited spinal cord dose
Disadvantages
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For distal tumors, significant cardiac volume
Entire extent of the esophagus treated
Treatment Planning – 3D Era
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Target Delineation
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PET-CT fusion
EUS findings
Definitions
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GTV – Gross Tumor Volume ( Tumor + grossly enlarged
LN)
CTV – Clinical Target Volume – Includes microscopic
disease
PTV – Planning Target Volume – accounts for setup error
and intra-fraction motion
Margins / Normal Tissue Tolerances

Margins / PTV definitions
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Superior / Inferior – GTV + 5 cm
Lateral – GTV + 2 cm
Normal Tissue Tolerances – Organs @ Risk
(OAR)
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Cord - max dose 45 -50 Gy
Lung V 20 Gy - 20 -30%
Liver V 30 Gy – 23- 30%
Kidney
Heart
Radiation Toxicities

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Esophagitis
Esophageal Stricture
Radiation Pneumonitis

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V20 Gy < 20-40%; V30 Gy < 18%; Mean Lung
Dose <20 Gy
Post-operative Pulmonary complications

MDACC study showed that the amount of Lung
that is spared from 5 Gy of radiation predictive
Radiation Toxicities
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Pericarditis
Cardiovascular disease
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V40 Gy < 30%
Radiation Nephropathy
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Limit dose to atleast 2/3 of 1 Kidney
Treatment Planning
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3D Treatment Planning (CT- based)
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Start AP/PA
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Treat to cord tolerance
39.6 – 41.4 Gy
Then off-cord
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2 field or 3 field
AP/RAO/LAO for cervical/upper thoracic lesions
AP/RPO/LPO for lower lesions
RAO/LPO for distal esophagus lesions
Treat to total 50.4 – 54 Gy
Treatment Planning - Evaluation

Dose Volume Histograms
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CT data allows to quantify dose received by
tumor as well as organs at risk
3D Planning
3D Planning
3D Planning
3D Planning
3D Planning
3D Planning
3D Planning
3D Planning - DVH
IMRT
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Intensity Modulated Radiation Therapy
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Clinical Rationale
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Tumors arise from/within normal tissues
Normal tissues often limit the radiation doses that can be
safely prescribed and delivered
Organs at risk in close proximity may have limited radiation
tolerance

IMRT allows for the reduction of radiation dose delivered
to normal tissue

Ability to maintain a high dose to the tumor
IMRT - Benefits

Normal Tissue sparing
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Reduced late toxicities
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Dose escalation
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Dose painting
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Ability to increase dose to areas of higher tumor burden
Re-irradiation
IMRT - Basics
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Ability to break a large treatment port into multiple
smaller subsets (field segments or pencil beams)
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Through utilization of MLCs or other intensity modulation
technology
A computer system to enable such field fragmentation
Computer system capable of performing inverse
treatment planning
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Defining the problem/solution upfront in numeric format
IMRT - Basics
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Multiple static non-coplanar radiation fields
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Each field has a unique radiation intensity profile
The fluency of radiation is altered during the delivery of the radiation field
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Multileaf collimator
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Planning CT scan (can be “fused” to an MRI or PET scan)
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The tumor/volumes and critical structures are drawn
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Prescription dose and dose constraints are programmed into the
radiation-planning software for generation of the radiation plan
Requirements for IMRT
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LINAC
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Beam modulation device
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MLC (multi-leaf collimator)
MlMiC (Peacock system)
Compensators
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(Inverse) treatment planning software
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QA program