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Histological types
- two histologic types
- - intestinal (glands)
- - diffuse (no glands)
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Morphological types
- - ulcerative (25%)
- - polyploid (25%)
- - superficial spreading (10%)
- - linitis plastica (10%)
- - the entire stomach is involved and looks thickened
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sign of Leser-Trelat
diffuse seborrheic keratosis
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Virchow's node
left supraclavicular space
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Sister Mary Joseph sign
mass in umbilicus (infiltration along falciform ligament)
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Blumer shelf
intraperitoneal metastases palpable on rectal exam
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Krukenberg tumors
ovarian metastases
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Role of CT
CT CAP: r/o liver, lung mets. 50% accurate for regional nodal involvement. T-stage accurate in 42-85%
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PET Scan
Combined PET/CT scan has high sensitivity (68%) then PET and CT alone.
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Role of EUS
EUS is indicative for detecting depth of tumor invasion. The accuracy of EUS for T staging 65-92% and N staging 50-95% but operator dependent.
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Role of EGD
- - 90-95% accurate in diagnosing advanced cancers
- Multiple biopsies (four to six), brush and lavage cytology improve accuracy
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Risk factors for Gastric Cancer
- - adenomatous polyps (not hyperplastic polyps)
- - atrophic gastritis
- - chronic gastritis (H.pylori), achlorhydria and pernicious anemia
- - intestinal metaplasia/dysplasia from h.pylori or bile reflux or radiation
- - ingestion of N-nitroso compounds and/or bacterial colonization of stomach (which produces N-nitroso compounds)
- - smoking (OR1.6)
- - prior gastric surgery (OR1.5-3). BII higher risk than BI
- - EBV infection (5-10% of gastric cancers)
- family history
- - FAP
- - E-cadherin (CDH1) mutants -> linitis plastica = hereditary diffuse gastric cancer
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T Staging
Tis
T1
T2
T3
T4
- Tis carcinoma in situ
- T1 invades lamina prop, confined to submucosa
- T2 invasion of muscularis propria (T2a) or subserosa (T2b)
- T3 penetrates serosa (visceral peritoneum) without invasion into adjacent structures
- T4 invasion of adjacent structures
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N STAGING
Nx
No
N1
N2
N3
- Nx cannot be assessed
- N0 No nodes
- N1 1-6 regional nodes
- N2 7-15 regional nodes
- N3 >15 nodes
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M STAGING
Mx
M0
M1
- Mx cannot be assessed
- M0 No distant metastasis
- M1 distan mets present (generally liver, peritoneum, distant LNs. Rare bone, ling, brain, soft tissue)
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What is R1
R1 indicates microscopic residual disease
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What is R2
R2 indicates gross (macroscopic) residual disease in the absence of distant metastasis
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Role of Surgery
- -if distal 2/3, subtotal gastrectomy. Proximal of distal margin of 4cm or greater. Use frozen sections for margins. Recon=B2 or Roux-en-y. No survival benefit for total gastrectomy
- - Total Gastrectomy for proximal (upper 1/3) tumor
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Lymphadenectomy
- Most controversial area in gastric cancer. Need 15 nodes for adequate staging.
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Describe N1,N2 and N3 lymph node station
- N1 refers to perigastric lymph node station along lesser curvature(station 1,3,5) and greater curvature (station 2,4,6).
- N2 involve nodes around left gastric artery (station 7), common hepatic artery (station 8), celiac artery station (9) and splenic artery (10,11)
- More distant lymph node including para-aortic are grouped as N3,N4.
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Describe D0,D1, and D2 lymph node dissection
- D0- Incomplete resection of N1 lymph node
- D1- D1 involves gastrectomy and removal of proximal or distal part of teh stomach or entire stomach (distal or total resection), including the greater and lesser omental LN which would include LN along the righ and left cardiac, alonger lesser and greater curv, suprapyloric along righ gastric artery infrapyloric area).
- D2- involve D1 + removal of the anterior leaf of transverse mesocolon, and all the nodes along corresponding arteies (i.e left gastric, common hepatic, celiac splenic hilum and splenic artery). A splenectomy (to remove station 10and 11) is required for D2 lymph node dissection for proximal gastric tumors.
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The most common location of gastric cancer is
Antrum has 40% of gastric cancers
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Adenomatous polyps confer what % of risk for gastric cancer? How do you treat these?
- Adenomatous polyps - 10-20% risk of cancer.
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- Tx: endoscopic resection
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Which one has the less favorable prognosis?Intestinal gastric cancer or diffuse gastric cancer?
Diffuse gastric cancer is less favorable prognosis than intestinal gastric cancer
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What is the survival rate for stage II disease in linitis plastica?
Stage II disease - <50% 5-year survival rate
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What are options for chemothreapy in linitis plastica?
- Chemotherapy - 5FU, doxorubicin, mitomycin C
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A patient with gastric cancer has an obstruction: What do you do to palliate this? How will your management change if it is a proximal vs distal lesion?
Obstruction - proximal lesions can be stented; distal lesion bypasses with gastrojejunostomy?
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Which type of gastric adenocarcinoma has glands on histology? Which type doesn't?
- Intestinal gastric cancer: Glands on histology
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- Diffuse gastric cancer (linitis plastica): No glands
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Which type of gastric adenocarcinoma has blood invasion on histology? Which type has lymphatic invasion on histology?
- Intestinal gastric cancer: Blood invasion on histology
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- Duffuse gastric cancer (linitis plastica): Lymphatic invasion
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In which populations do you find intestinal gastric cancer
Intestinal gastric cancer: increased in high-risk populations, older men
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Role of CEA
- CEA elevated in 30% of cases
- - (if + useful for surveillance)
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