Contouring guidelines pancreatic malignancies

1. CONTOURING GUIDELINES-
PANCREATIC MALIGNANCIES
DR. P. MANASA/ DR. ASTHA
SRIVASTAVA
MODERATOR – PROF. S. PATHY

2. Introduction
 The number of new cases diagnosed per year
is 10860 (0.94%) and mortality rate is about
10528 (1.3%) in 2018.
 Seventh leading cause of cancer mortality ,
although only the twelfth most common cancer
worldwide.
Globocan 2018

3. Anatomy

4.  Risk factors –
 Chronic pancreatitis, smoking, alcohol consumption,
Helicobacter pylori infection.
 Factors associated with metabolic syndrome such as
obesity and glucose intolerance.
 Familial - BRCA1/2 and PALB2 mutations, Peutz-
Jeghers syndrome, FAP, HNPCC.

5. Clinical presentation &
Evaluation
 Pain, weight loss, jaundice.
 Recent onset/ exacerbation of diabetes mellitus,
migratory thrombophlebitis(Trousseau’s sign).
 Palpable abdominal mass, ascites,
supraclavicular nodes.

7.  Investigations –
 Computed Tomography (CT) scan
 Endoscopic Ultrasound (EUS) for evaluating
resectability in patients with localised disease.
 Magnetic Resonance Imaging (MRI) if allergic to
iodinated contrast.
 FNAC/ Biopsy
 Positron Emission Tomography (PET) may be
considered but contribution to target delineation has
not been fully characterised.
 Lab workup- CBC, CEA, CA 19-9,LFT.

8. Gunderson and Tepper 4th edition

10. CT Simulation
 CT simulation with oral and IV contrast (unless
contraindicated)
 Patients are generally asked not to eat any
large meals 2–3 h prior to simulation and
treatment to avoid significant interfraction
variation in stomach distention.
 Arms should be above the head, orifit /vaclock
for immobilisation.

11.  Planning scan should be done(minimum of 3
mm cuts) with a scan from carina to iliac crest.
 For patients treated with respiratory gating or
without a specific motion-management
technique, a four dimensional (4D) CT is
necessary to evaluate the degree of tumor
motion.

13. Target volumes: GTV
 By definition there is no gross tumor volume (GTV) at
time of radiotherapy because the tumor has been
resected.

14. Treatment Volumes: CTV
 Typical anatomical landmarks that can help in CTV
delineation include:
1. Pancreas - L1-L2
2. Celiac axis - T12
3. SMA - L1

15.  CTV is the area with the highest likelihood for residual
subclinical tumor.
 Imperative to review pre-op imaging , operative notes
and histopathology report at the time of treatment
planning.

16. 1) Post op tumor bed
2 ) Anastomoses
 Pancreaticojejunostomy(PJ)
 Choledochal or hepaticojejunostomy

17. 3) Abdominal nodal regions
 Peripancreatic
 Celiac
 Superior mesenteric
 Porta hepatis
 Para-aortic

18. ROI Delineation:Post-op Bed
 Location of tumor should be reviewed and contoured
based on pre-op imaging.
 Surgical clips placed should only be included if there is
documentation from the surgeon intraoperatively such
as close margins or specific tumor related .

19. ROI Delineation:PJ and HJ
 PJ is identified by following pancreatic remnant medially
and until the junction with the jejunal loop is noted.
 HJ is identified by following air in biliary tree to CHD or
CBD remnant to jejunal loop , or by following PV out of
liver to jejunal loop region.

20. ROI Delineation:Ao and PV
 Aorta(Ao) extending from top of the upper most PV,CA or
SMA slice to the bottom of L2 or L3.
 Portal vein(PV) is contoured from the bifurcation of the PV .
The PV bifurcation can be extrahepatic or almost
intrahepatic.
(portion of portal vein running anterior and medial to IVC
and stop prior to confluence of SMV or splenic vein).

21. ROI Delineation:CA and SMA
 Celiac artery (CA): The most proximal 1.0-1.5 cm of the
CA and should include up to the first branching.
 Superior mesenteric artery (SMA): The most proximal
2.5-3.0 cm of SMA.

22. ROI Expansions
 Pancreaticojejunostomy, portal vein, superior mesenteric
artery and celiac artery are expanded by 0.5-1 cm.
 Aorta ROI is given asymmetric expansion; 2.5-3 cm
towards right , 1cm towards left, 0.2 cm posteriorly and 2
-2.5 cm anteriorly.

23.  The CTV is then created by merging the ROI expansions .
 The posterior margin should follow the contour of the
anterior aspect of the vertebral body without including
more than 0.5 cm of the anterior vertebral body anterior
edge.

24.  If the PJ cannot be identified, the CTV should be
generated
without it.
 If the CTV with the noted expansions protrudes into a
dose limited normal organ such as the liver or stomach or
kidney, it should be edited to be adjacent to the relevant
structure

25.  PTV – 0.5 cm expansion on CTV

28. OARs
 Liver
 Kidney
 Stomach
 Spinal Cord
 Heart
 Duodenum
 Small Bowel
 Lungs

48. Unresectable Pancreatic
Adenocarcinoma
 GTV:Gross visible disease
 CTV:GTV is expanded by 1 cm; this expansion is then added
to the nodal CTV
 PTV:Expansion on the CTV by 5 mm (receives
5,040 cGy in 180 cGy fractions)
 PTV boost:Expansion on the GTV by 3–5 mm
margin,shrinking the margin to <3 mm to minimize overlap
with the duodenum.
P.B Romesser et al,Target Volume Delineation for Conformal and Intensity-Modulated Radiation
Therapy

49. Treatment prescription
 Radical (in combination with chemotherapy with
Gemcitabine or 5-FU)-
45-50.4 Gy in 25-28 fractions of 1.8 Gy given in 5-5 ½
week.Surgical resection may be followed 8 weeks post
RT.
 Adjuvant (resected)-
45-46 Gy in 1.8-2.0 Gy/# to tumor bed, surgical
anastomoses and adjacent lymph node basins,
followed by additional 5-9 Gy to the tumor bed and
anastomoses if clinically appropriate.