Panel discussion on contouring and simulation for gastric cancers: recommendations and practises

1. Contouring for Gastric Cancers: How Do I DoContouring for Gastric Cancers: How Do I Do
It?It?
Dr. Ashutosh Mukherji
Additional Professor,
Department of Radiotherapy,
Regional Cancer Centre, JIPMER

2. BACKGROUND…….
• Stomach cancer 5th most common cancer in males and
7th most common cancer in females in India. [V Rao DN,
Ganesh B. Estimate of cancer incidence in India in 1991. Indian J
Cancer, 1998]
• Surgery is standard of treatment; high incidence of
local and distal recurrence seen even after adequate
radical surgery; hence need for adjuvant therapy.
[D’Souza MA, Singh K, Shrikhande SV. J Cancer Res Ther 2009]
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3. 5 Year Survival by Stage
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4. RADIOTHERAPY FOR GASTRIC
CANCERS
When is radiotherapy indicated in gastric
cancers?
•Neoadjuvant
•Adjuvant
•Radical
•Palliative
4

5. • Adjuvant chemo-RT to a dose of 45 Gy with fluoro-pyrimidine based
concurrent chemo is indicated in all locally advanced and node positive
disease who have not received pre-operative chemo and / or RT.
• Definitive chemo-RT to a dose of 45-50.4 Gy with fluoro-pyrimidine based
concurrent chemo (level 1 evidence) is indicated in all locally advanced
and node positive disease who are inoperable / medically unfit for
surgery.
• Target volume for all gastric cancers would include body of pancreas, full
stomach bed and all regional nodes. Depending on part of stomach
involved, CTV may include also diaphragm, duodenum or lower
esophagus.
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As per NCCN guidelines

6. RADIOTHERAPY FOR GASTRIC
CANCERS
What should the field cover?
•Local ?
•Regional ?
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7. 7

8. Stomach and Regional Anatomy–
for RT Planning
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9. Which lymph nodes have to be included in the CTV?
• individualize for GE-junction/Cardia (proximal), Corpus (middle)
and antrum (distal) tumors
• GE-junction/Cardia/proximal 1/3: para-oesophageal, perigastric,
hepatogastro lig, perigastric, ,celiac (left gastric artery, celiac
axis), splenic hilum, suprapancreatic, porta hepatis,
pancreaticoduodenal [stations 1-4;7,9-13]
• Corpus/middle 1/3: perigastric, suprapyloric, infrapyloric, celiac
(left gastric artery, common hepatic artery and celiac axis),
splenic hilum, suprapancreatic, porta hepatis,
pancreaticoduodenal [stations 3-13]
• Antrum/distal 1/3: perigastric, suprapyloric, infrapyloric, splenic
artery, pancreaticoduodenal, porta hepatis, celiac (left gastric
artery, common hepatic artery and celiac axis), suprapancreatic
[stations 3-9;11-13] 9

10. Stomach and Regional Lymph
Nodes – for RT Planning
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11. Stomach and Regional Lymph
Nodes – for RT Planning
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12. RADIOTHERAPY FOR GASTRIC
CANCERS
Define the simulation protocol?
•Immobilisation?
•Positioning and Simulation ?
•Imaging and image capture ?
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13. • Radiotherapy planning CT scans of 3–5 mm thickness
• Patient in the supine position with arms overhead, from top of
diaphragm (for stomach) or carina (for tumor of GE junction or
cardia) to the bottom of L4.
• Patients should be fasted for 2–3 h.
• Intravenous contrast is preferred to demonstrate blood vessels
and guide clinical target volume (CTV) delineation, particularly
for lymph nodes
• Preoperative CT scans should be used to aid identification of
preoperative tumor volume and nodal groups to be treated
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14. RADIOTHERAPY FOR GASTRIC
CANCERS
Define the target volumes?
•Gastric bed or remnant or full stomach
•Anastomoses
•Lymph nodes
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15. 15
The hepatogastric ligament should
preferably be treated in all cases as it is at
high risk of recurrence. It represents the
part of the lesser omentum that runs
between the lesser curvature of the
stomach and liver and contains the left and
right gastric nodes that are not always
completely removed at surgery.

16. 16

17. 17

18. RADIOTHERAPY FOR GASTRIC
CANCERS
• Define margin for PTV?
• Account for respiratory and peristaltic
motion?
• Account for Bowel movements?
• PTV overlap with OARs how to deal with it?
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19. • CTV+ margin considering organ
motion and setup uncertainties.
• A minimum expansion of 1 cm is
suggested.
• Create non-PTV OARs for
organs overlapping with PTVs:
NonPTVSmallBowell,
NonPTVRectum,
NonPTVBladder, etc.

20. 20
Acknowledgement of organ motion
and use of motion management
techniques in contouring, planning
and delivery of irradiation can help
decrease OAR dose and improve
target coverage.

21. RADIOTHERAPY FOR GASTRIC
CANCERS
• Define the main OARs?
• Defining anatomical extent of the OARs and
Lymph nodal volumes from CT scans?
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22. 22
LN-CTV IN A NORMAL
INTACT STOMACH SCAN
J.Y. Wo et al Practical Radiation Oncology: January-March 2013

23. LN-CTV AFTER TOTAL GASTRECTOMY
23J.Y. Wo et al Practical Radiation Oncology: January-March 2013

24. 24
LN-CTV AFTER SUB-TOTAL GASTRECTOMY
J.Y. Wo et al Practical Radiation Oncology: January-March 2013

25. 25
ADJUVANT LN-CTV – CARDIA / GE JUNCTION TUMOURS

26. 26
ADJUVANT LN-CTV – BODY / MIDDLE THIRD TUMOURS

27. 27
AJCC stage Whether to include
Remnant stomach
Tumour bed
volume
Nodal coverage
Cardia/prox
third of
stomach
Preferred, but spare 2/3 of
one kidney (usually right)
T category
dependent
N classification
dependentAntrum/distal
third of
stomach
Yes, but spare 2/3 of one
kidney (usually left)
T3N0,
Variable, dependent on
surgical pathological
findings
Prox: medial left
hemidiaphragm,
adjacent body of
pancreas (±tail)
Distal: head of
pancreas (±body),
first and second
part of duodenum
Prox: none or PG
Distal: none or PG
Optional: CN, SplNs,
HNpd, PHN

28. 28
AJCC
stage
Whether to include
Remnant stomach
Tumour bed
volume
Nodal coverage
T4aN0
Variable, dependent on surgical
pathological findings
Prox: medial left
hemidiaphragm, adjacent
body of pancreas (±tail)
Distal: head of pancreas
(±body), first and second
part of duodenum
Prox: none or PG
Optional: PEN, MN, CN
Distal : none or PG
Optional: CN, SplNs,
HNpd, PHN
T4bN0
Prox: variable, dependent on
surgical pathological finding.
Distal: preferable, dependent on
surgical
pathological finding
As for T4aN0 plus sites of
adherence with 3–5-cm
margin
Prox: nodes related to
sites of adherence
±PG,PEN, MN, CN
Distal: nodes related to
sites of adherence
±PG, SplNs, HNpd, CN,
PHN
T1–3 N+ Preferable
Not indicated for T1–2,
as above for T3
T4a/bN+ Preferable As for T4a/bN0
As for T1–3 N + and
T4bN0

29. RADIOTHERAPY FOR GASTRIC
CANCERS
• Which are dose limiting OARs?
• Any order of preference for defining OAR
constraints?
• Dose constraints for OARs?
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30. The CT Images Are Contoured and
Labelled to Identify The Structures

31. THANK YOUTHANK YOU
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