radiotherapy techniques in cancer esophagus

1. RT Planning
Techniques In
Ca Esophagus
Presenter- Dr. Rashmi
Moderator- Dr. Arvind

4. Radiation
• Patients can be treated by
• EBRT
 Conventional:2D
 3 D CRT
 IMRT
 IGRT
• Palliative RT
• Brachytherapy (ILBT)

5. IMMOBILISATION
CECT/ PET-CT
SCAN VOLUME
DELINEATION
PLANNING
TREATMENT
DELIVERY
PRE-TREATMENT
IMAGING
PLAN
VERIFICATION

6. SIMULA
TION
Extent of the disease should be known based on
 Barium swallow
 CT
 Endoscopy
 PET
Radiographic simulation used in 2D era- CT simulation preferred now

7. Positioning & Immobilisation
Patient Positioning:
• Cervical and upper thoracic Esophagus: Supine, arms by the side
• Middle and Lower third:
• Supine with arms above their head if AP – PAportals are being planned
• Prone position may be considered if posterior obliques are being included. Esophagus is
pulled anteriorly and spinal cord can be spared.
• During simulation, the patient is positioned, straightened, and immobilized on the
simulation table.
• For cervical and upper thoracic lesions, an immobilization mask is used
• Palpable neck disease should be marked with a radiopaque wire.

8. Image acquisition
 Need of contrast:
• I.V contrast helps in delineation of mediastinal and abdominal vascular nodal basins
• Also allow to discern normal vasculature from other adjacent normal structures, and potential
adenopathy
• Oral contrast helps in better visualization of the esophageal lumen and define the extent of
mucosal irregularity.
• Scan of the entire area of interest with margin is obtained.
• At minimum, 3- to 5-mm slices should be used, allowing accurate tumor characterization, as
well as improved quality of digitally reconstructed radiographs.

9. Advancement In Simulation
Techniques
OBJECTIVES:
• to reduce target motion with respiration
• Reduce margins as used in free breathing techniques
• assess tumoral motion, facilitating appropriate margin placement
TECHNIQUES:
• breath-hold techniques
• abdominal compression devices
• respiratory gating
• 4DCT scan

10.  PET imaging is increasingly used in the clinical management of patients undergoing
radiotherapy.
 PET/CT has a high prognostic value in patients undergoing CRT for esophageal cancer and can
therefore be useful to guide treatment decisions.
 PET/CT has a high specificity and sensitivity in detecting involved nodes in esophageal cancer
and should therefore be considered for pre-treatment imaging in patients with esophageal
cancer

12. TREATMENT PLANNING
TARGET DESIGN

13. GROSS TUMOR VOLUME
• Accurate definition of primary and nodal gross disease is paramount in
radiation esophageal cancer planning.
• Barium swallow, EUS, and CT, as well as PET scan when available is
used for GTV definition

14. CLINICAL TARGET VOLUME
• Accurate delineation of CTV is critical in the effective management of Ca oesophagus
using RT
• Improves the probability of local control and reduce the risk of complications.
• No consistent standards on the margins added to the GTV
• Most precise method for delineating a reasonable CTV is to combine
information from all diagnostic test
• It allows the detection and prediction of subclinical lesions based on tumour
characteristics such as the pathological type, differentiation, T disease, length and
lymph node status

15. Subclinical Lesions In Ca Esophagus
• CTV of esophageal carcinoma should cover the primary tumor and all detected secondary lesions
• Secondary lesions frequently include
direct invasion (DI),
intra-mural metastasis (IMM),
multicentric occurrent lesions (MOL),
vascular invasion(VI),
microscopic lymph node metastasis (LNMM)
isolated tumor cells (ITC)
perineural invasion (PNI)

16. Subclinical Lesions And The
Primary CTV (CTVp)
CTVp includes GTVp + the following:
• Direct invasion (DI)
• Intra mural metastasis (IMM)
• Multicentric occurent lesion (MOL)
• vascular invasion (VI)
• Peri neural invasion (PNI)

17. CTV for lymph nodes (CTVn)
CTVn includes GTVn + the following:
• Microscopic lymph node metastatis
• Isolated tumor cells: skip metastasis

18. CTV for lymph nodes (CTVn)
For upper thoracic esophageal carcinomas:
• superior prophylactic nodal irradiation volume should include the cervical paraesophageal and
supraclavicular lymph nodes, and the superior margin should include the subcarinal lymph nodes.
For middle thoracic esophageal carcinomas:
• prophylactic treatment volume should be customized depending on the clinical circumstances; more
thorough coverage of the mediastinal lymph nodes should be considered, especially in patients who are
generally in good condition
For lower thoracic esophageal carcinomas:
• superior margin should include the subcarinal lymph nodes, and the inferior margin should include the left
gastric lymph nodes and common hepatic artery lymph nodes.

19. ELECTIVE NODAL
IRRADIATION VS INVOLVED
FIELD RT

20. ELECTIVE NODAL IRRADIATION
• CONS
• Increased risk of nodal failure
• Large RT fields
• Increased toxicity
• No improvement in OS
• Additional diagnostic test needed to
accurately define involved nodes
• Chemotherapy reduces micrometastasis
• PROS
• High risk of
micrometastasis
• Skip metastasis

21. •In patients treated with 3D-CRT for esophageal SCC, the omission of elective nodal
irradiation was not associated with a significant amount of failure in lymph node
regions not included in the planning target volume.
•Local failure and distant metastases remained the predominant problems.
•A longitudinal margin of 3 cm from the GTV to the CTV1 is probably enough

22. 1.Recurrene pattern(in-field)
Predominant failure pattern in with esophageal SCC was local in-field or distant failures. Regional nodal
recurrence (out-of-field) was infrequent(8%) in the absence of elective node irradiation.
2.Biological behavior of the disease
Esophageal cancer is characterized by a high rate of nodal involvement and its spread pattern is not always
predictable. Also, skip node metastases are frequently observed. Thus the biological behavior of this disease
makes it difficult to define in advance the extent of coverage of elective nodal irradiation.
3.Toxicities
If distant lymph node areas were irradiated prophylactically, patients would then experience more severe
radiation complications and have a poorer treatment tolerance.

23. In CRT for esophageal SqCC, ENI was effective for preventing regional nodal failure. The
UPPER THORACIC esophageal carcinomas had significantly more local recurrences than
the middle or lower thoracic sites.

24. • Retrospective analysis
• 79 patients with locally advanced ESCC underwent 3D-CRTor IMRT using IFI or elective
nodal irradiation (ENI) according to the target volume.
• The patterns of failure were defined as local/regional,in-field, out-of-field regional lymph node
(LN) and distant failure.
• With a median follow-up of 32.0 months, failures were observed in 66 (83.6%) patients.

25. Target definition
• Delineation of clinical target volume (CTV) was based on CT, barium esophagogram, and
endoscopic examination.
• Esophageal wall thickness of more than 0.5cm and positive LNs were included in the gross tumor
volume (GTV)
• LNs that were well vascularized, measured more than 8 mm in the short axes, and showed
central necrosis or extracapsular extension in CT were considered malignant
• The total dose of GTV was 58-66 Gy/29-33F. At the same time, the volume of CTV was
appropriately adjusted on the basis of the human anatomic structure so that the maximum
dosage in the spinal cord did not exceed 45 Gy.

26. Pattern of failure
• Local/regional failure IFRT vs ENI (52.8 vs 55.8%)
• Distant failure (27.8 vs 32.6%) was lower in the ENI compared with the IFI group in 3 years,
with no statistical significance (p=0.526 and 0.180, respectively).
• The cumulative incidence of regional LN failure was 25.6% for the IFI group compared
with 19.4% for the ENI group (p=0.215).

27. RADIATION FIELD DESIGN

28. ENLARGED RADIATION FIELDS
• Enlarged fields (e.g., whole-esophagus or whole-mediastinum) have been used in
past to treat secondary lesions located far from the primary tumor.

29. Treatment Planning 2D Era – RTOG8501
• RTOG 8501 compared CRT (50 Gy) to RT alone (64Gy)
• Mid/Lower Esophageal Cancers
• Initial Field was AP/PA to 30Gy/15#
• Extended from SCV region to GE junction
• Omitted SCV nodes in lower esophageal tumors
• Boost field was tumor + 5 cm sup/inf with a 3 field or opposed obliques to dose of 20 Gy in 10 fractions
• Advantages
• AP/PA limited lung dose
• Replacing PAwith oblique fields limited spinal cord dose
• Disadvantages
• For distal tumors, significant cardiac volume
• Entire extent of the esophagus treated

30. ENLARGED RADIATION FIELDS
 RTOG 94-05 trial:
• 5 cm margin beyond superior and Inferior extent of the primary tumor. lateral, anterior, and
posterior borders of the field were ≥ 2 cm beyond the borders of the primary tumor
• However, these studies did not demonstrate improved local control or survival despite causing
intolerable toxicities.
• Rarely, individual lesions may be located distant from the primary tumor, therefore empirical
irradiation of whole esophagus or mediastinum is likely unnecessary.

32. CONCLUSION
• A 3 cm margin proximally and distally would cover microscopic disease in 94% of all SCCs.
• For GE junction tumours, a 3cm margin proximally and 5cm distally would allow similar
coverage.
• Most contemporary radiation trials used margins of 3 to 5 cm cranially and caudally on the
GTV, along with a 2-2.5cm radial margin.
LIMITATION:
• Investigators did not note the occurrence of each secondary lesion.
• Small sample size

33. LIMITED FIELD TECHNIQUES
• Most contemporary radiation trials used margins of 3 to 5 cm cranially and caudally on
the GTV, along with an approximate 2-cm radial margin
• With disease located at or above the carina (or middle/upper one-third of the
esophagus), fields inclusive of the supraclavicular lymph node basins, whereas celiac
axis nodal basin coverage was recommended for disease of the distal esophagus.

34. 2D RADIATION TECHNIQUE
• Field border defined on basis of anatomical landmarks

35. FIELD DESIGN: CERVICAL ESOPHAGUS
Challenging due to
• changing contour from the neck to the thoracic inlet
• Limited dose constrains of spinal cord

36. EBRT – Cervical Esophagus
FIELD DESIGN
• lateral parallel opposed or oblique portals to the primary tumor and a single
anterior field for the supraclavicular and superior mediastinal nodes
• 2 anterior obliques and 1 posterior or 2 posterior obliques and 1 anteriorfield
• AP – PAfollowed by opposed obliquepair.
• 4 field box with soft tissue compensators followed by obliques.
TARGET
• Lesions in the upper cervical are treated from the laryngopharynx to the
carina, depending on extent of disease.
• Supraclavicular and superior mediastinal nodes are irradiated electively
• Superior Border: C7
• Inferior Border: T4 (carina)
• 2 cm lateral margins.

38. EBRT – Thoracic Esophagus
• Superior Border: 5 cm proximal to superior extent of disease.
• Inferior Border:
• Middle third - GEJ as visualised by Barium swallow
• Lower third - Coeliac plexus (L1) to be included.
• AP - PAfollowed by 1 Anterior and 2 Posterior oblique pairs
• 4 Field: AP - PA& opposed laterals – for mid 1/3rd lesions.
• AP - PAto deliver 36-44 Gy followed by posterior obliques to reach the full dose.

40. Treatment Planning – 3D Era
Definitions
• 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

42. 3D CONFORMAL RT
Advantages over 2D planning
3-dimensional visualisation of target and OARs
3-dimensional reconstruction
Creation of a “beam’s-eye” view of varying fields
Dose–volume Histogram data can also be generated
allowing improved conformality around target structures and improvements in
normal-tissue sparing

43. Treatment Planning
• 3D Treatment Planning (CT- based)
• StartAP/PA
• Treat to cord tolerance
• 39.6 – 41.4 Gy
• Then off-cord
• 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

44. 3D Planning
Treatment Plan
•3D-CRT
•AP/PA to 36 Gy followed by 3-field boost to 45 Gy
•Additional cone down (Boost PTV) to 50.4 Gy
•Concurrent chemotherapy with carbo/taxol

45. Treatment Planning - Evaluation
• Dose Volume Histograms
• CT data allows to quantify dose received by tumoras well as organs at risk

46. Typical Radiation Field for Cervical or
Upper Esophagus
radiation

47. Typical Radiation Field for Middle Esophagus

48. Typical Radiation Field for Lower Esophagus

49. Typical Radiation Field for Lower Esophagus

50. Radiation Dose Guidelines
Pre-Operative: 41.1 – 50.4Gy (1.8-2.0/day)
Post-Operative: 45 – 50.4Gy (1.8-2.0/day)
Definitive: 50 – 50.4Gy (1.8-2.0/day)
Higher dose (60-66 Gy) may be considered in cervical esophagus where
surgery is not planned, but there is little evidence of benefit > 50.4Gy

51. IMRT

52. IMRT
• Clinical Rationale
• 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

53. IMRT - Benefits
• Normal Tissue sparing
• Reduced late toxicities
• Dose escalation
• Dose painting
• Ability to increase dose to areas of higher tumor burden
• Re-irradiation

54. IMRT - Basics
 Ability to break a large treatment port into multiple smaller subsets (field
segments or pencil beams)
• Through utilization of MLCs
• A computer system to enable such field fragmentation
 Inverse treatment planning
 Prescription dose and dose constraints are programmed into the radiation-
planning software for generation of the radiation plan

55. IMRT in Esophageal Cancer
• With the exception of a small series that used IMRT to treat patients with
cervical esophageal primaries, most data regarding IMRT for esophageal
malignancies has been limited to dosimetric analyses
• Found superior to 3DCRT in generating conformal and homogeneous
target coverage
• Reducing dose to Spinal cord, Heart and Lung

56. 3-D vs. IMRT

57. IMRT

58. IMRT

59. IMRT

61. BRACHYTHERAPY

69. PALLIATIVE RT
• Palliative EBRT provides good symptom control in patients with symptomatic
esophageal cancer. A higher dose schedule was related to a longer time to
second intervention. Hence, selection based on life expectancy is vital to
prevent unnecessary long treatment schedules in patients with expected
short survival and limit the chance of second intervention when life
expectancy is longer.
• (20 Gy in 5 fractions, 30 Gy in 10 fractions or 39 Gy in 13 fractions)

70. Palliative EBRT provides good symptom control in the majority of patients with
symptomatic esophageal cancer. A higher dose schedule was related to a longer time to
second intervention.

71. Initial palliative short-course radiotherapy followed by chemotherapy is a promising treatment
strategy that can provide long-lasting relief of dysphagia in patients with esophageal
adenocarcinoma.

72. Toxicities after RT
• Esophagitis
• Dysphagia
• Esophageal stenosis
• Esophageal stricture
• Radiation pneumonitis
• Cardiac toxicities- effusion, pericarditis

74. THANK YOU