5. • On the lesser curvature, left gastric artery the
coeliac axis, forms an anastomotic arcade with
the right gastric artery, which arises from the
common hepatic artery.
• Branches of the left gastric artery pass up
towards the cardia.
• Gastroduodenal artery, which is also a branch
of the hepatic artery, passes behind the first
part of the duodenum → bleeding duodenal
ulcer.
6. • Gastroduodenal artery then divided to give
superior pancreaticoduodenal artery and right
gastroepiploic artery.
• Right gastroepiploic artery runs along the
greater curvature of the stomach, eventually
forming an anastomosis with left
gastroepiploic artery, a branch of the splenic
artery.
• Fundus of the stomach is supplied by the vasa
brevia (or short gastric arteries), which arise
near the termination of the splenic artery.
7. Venous drainage
• Equal to arterial supply
• Those along the lesser curve ending in the
portal vein and those on the greater curve
joining via the splenic vein.
• Coronary vein - runs up the lesser curve
towards the oesophagus and then passes left
to right to join the portal vein → markedly
dilated in portal hypertension.
9. • Antrum → right gastric lymph node superiorly
and the right gastroepiploic and subpyloric
lymph nodes inferiorly.
• Pylorus → right gastric suprapyloric nodes
superiorly and the subpyloric lymph nodes
situated around the gastroduodenal artery
inferiorly.
• Efferent lymphatics from the suprapyloric
lymph nodes converge on the para-aortic
nodes around the coeliac axis
10. • Efferent lymphatics from the subpyloric lymph
nodes pass up to the main superior
mesenteric lymph nodes situated around the
origin of the superior mesenteric artery.
• Lymphatic vessels related to the cardiac orifice
of the stomach communicate freely with those
of the oesophagus
11. Nerves
• Intrinsic nerves – 2 plexus
– Myenteric plexus of Auerbach
– Submucosal plexus of Meissner
• Extrinsic nerves, derived from vagus nerve.
• Vagal plexus around the oesophagus
condenses into bundles that pass through the
oesophageal hiatus.
• Sympathetic supply mainly from coeliac
ganglia.
12. The anatomy of the anterior and posterior vagus nerves in relation to the stomach.
13. Risk Factor & Etiology of GIST
Ahmad Abid Abas [2]
Reference : American Cancer Society (GIST)
15. Etiology
• Unknown etiology. No known lifestyle related or
environmental causes.
• ‘Genes and protein changes theory in GIST cells ’
• Understanding this information will help to
diagnose and treat this cancer.
16. Etiology
• Genes = DNA
• Oncogenes – Certain genes that help cells
grow and divide.
• Tumour suppressor genes – Genes that helps
slow down cell division or cause cells to die at
right time.
17. Etiology
• In GIST, there is a change in oncogene called
c-kit.(Receptor tyrosine kinase mutations)
• It directs cell to make a protein called KIT.
• Normally c-kit gene is inactive.Active during
there is a need for Interstitial Cells of Cajal*.
*(as pacemaker,controlling motility)
• In GIST, c-kit is always mutated and active.
• 85% of GIST have mutation in c-kit.
18. Etiology
• About 15% GIST patient have mutation in
another protein receptor called, PDGFR.
(Platelet-Derived Growth Factor)
• The gene changes is now understood by
researchers but it’s still not clear what might
cause this changes.
20. In adult GISTs
• Stomach-60%
• Small intestine-30%
• Duodenum-5%
• Colorectum-<5%
• Esophagus and appendix-<1%
GISTs are frequently diagnosed
incidentally during endoscopic or surgical
procedure. They are either asymptomatic
or associated with non specific symptoms
21. Symptoms
Most common symptoms are:
• Vague, non specific abdominal pain or
discomfort.
• Early satiety or a sensation of abdominal
fullness.
GISTs may also produce symptoms secondary
to obstruction or hemorrhage.
Symptoms of haemorrhage
• malaise, fatigue, or exertional dyspnea.
Symptoms of obstruction can be site-specific
• (eg, dysphagia with an esophageal GIST,
22. Signs
• Abdominal mass
• Vital sign abnormality, shock d.t
GI blood loss
• Distended tender abdomen d.t
bowel obstruction
• Jaundice if obs. involving ampulla
• Sign of peritonitis if perforation
has occurred
24. LAB TEST
No xpecific test,the following tests are generally ordered in the
workup of the patient who presents with nonspecific
abdominal symptomatology;
• Complete blood cell count
• Coagulation profile
• Serum chemistry studies
• BUN and creatinine
• Liver function tests and amylase and lipase values
• Type and screen, type and crossmatch
• Serum albumin
25. IMAGING : BARIUM STUDY
• can usually detect GISTs that have grown to a size
sufficient to produce symptoms.
• a filling defect that is sharply demarcated and is
elevated compared with the surrounding mucosa,
• the contour of the overlying mucosa is smooth unless
ulceration has developed because of growth of the
underlying tumor
26. IMAGING : CT
• It provides comprehensive information regarding the
size and location of the tumor and its relationship to
adjacent structures.
• CT scanning can also be used to detect the presence
of multiple tumors and can provide evidence of
metastatic spread.
28. IMAGING ; MRI
• MRI has not been studied as intensively as CT
scanning in the application of diagnosing
GISTs.
• It appears to be just as sensitive as CT
scanning
29. IMAGING ; PET
• has recently been touted as an excellent study for
detecting metastatic disease. It has also been used to
monitor responses to adjuvant therapies such as
imatinib mesylate.
30. ENDOSCOPY
• Endoscopic features of GISTs include the
suggestion of a smooth submucosal mass
displacing the overlying mucosa.
• Some may be associated with ulceration or
bleeding of the overlying mucosa from
pressure necrosis.
31. ENDOSCOPIC ULTRASOUND
• The typical endoscopic ultrasonographic appearance
of a GIST is a hypoechoic mass situated in the layer
corresponding to the muscularis propria.
• Fine-needle aspiration biopsy specimens also may
be obtained via the endoscope under sonographic
guidance.
35. Surgical treatment
• Surgery is the mainstay of therapy for
nonmetastatic GISTs
• Routine lymphadenectomy is not indicated, as
lymph node involvement is very rare.
• The decision of appropriate laparoscopic
surgery is affected by tumor size, location, and
growth pattern
36. • After surgery, patients who may have a high
risk of recurrence often receive imatinib for at
least three years.
• This is a type of treatment called adjuvant
therapy
37. Indications for surgery
• For small gastric tumors, wedge resection is
adequate, if technically possible.
• Larger tumors necessitate subtotal or total
gastrectomy.
• Also consider resection in patients with
recurrent disease, manifested as a solitary
lesion in the liver or peritoneal cavity.
• in cases of disseminated disease, consider
palliative
38. • For locally invasive tumors, en bloc resection
of adjacent involved organs, such as colon,
spleen, or liver.
• The goal is complete resection of the mass
without disruption of pseudocapsule
• Segmental resection with negative
microscopic margins is the preferred
intervention
39. Targeted Therapy
• Targeted therapy is a treatment that targets
the tumor’s specific genes, proteins, or the
tissue environment that contributes to the
tumor’s growth and survival.
• Evidence of benefit in
1. Treatment of advanced GIST
2. As adjuvant to 1ry tumour resection
40. • Tyrosinekinase inhibitor imatinib (Glivec/Gleevec)
,a drug initially marketed for CML was found to
be useful in treating GISTs
• It is usually given alone or in combination with
surgery (either before or after surgery) and is
given for a long time.
• For patients with GIST that has spread to other
parts of the body, imatinib is taken for the rest of
the patient’s life to help control the tumor.
41. Imatinib Mesylate: Mechanism of Action
•Imatinib mesylate occupies
the ATP binding pocket of the
c KIT kinase domain
c KIT
•This prevents substrate
phosphorylation and
signaling
P
Imatinib ATP
•A lack of signaling inhibits mesylate
proliferation and survival P P P
SIGNALING
Savage and Antman. N Engl J Med. 2002;346:683.
42. • The usual dose of imatinib is 400 milligrams
(mg) daily.
• The most common side effects of imatinib
are fluid accumulation, rash, nausea, and
minor muscle aches.
• Serious but relatively rare side effects include
bleeding and inflammation of the liver.
43. • Patients who develop resistance to imatinib may
respond to the multiple tyrosine kinase
inhibitor sunitinib (marketed as Sutent)
• Itis a tyrosine kinase inhibitor called an anti-
angiogenic that is focused on stopping
angiogenesis
• Because a tumor needs the nutrients delivered
by blood vessels to grow and spread, the goal of
anti-angiogenesis therapies is to “starve” the
tumor.
44. Radiation therapy
• Radiation therapy is not often used for GIST,
as it is unclear whether it helps to shrink the
tumor.
• However, it may be used as a palliative
treatment to relieve pain or stop bleeding.
• Side effects from radiation therapy include
tiredness, mild skin reactions, upset stomach,
and loose bowel movements.
