STOMACH

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STOMACH

• James Taclin C. Banez, MD, FPSGS, FPCS

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Anatomy

• Arterial blood supply
• Lymphatic drainage
• Nerve supply

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PHYSIOLOGY

• Function
• Digestion of food, reduce the size of food
• Acts as reservoir
• Absorption of Vit. 12, iron and calcium
• Stimulant of Gastric secretion
• Gastrin -----gt () parietal cell
• Acetylcholine (vagus) ---gt () gastric cells
• Histamine (mast cells) ---gt parietal chief cells

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PHYSIOLOGY

• BAO 2 5 meq of acid/hr. (vagal tone and basal
  histamine secretion)
• MAO
• Cephalic (vagus) ---gt () parietal G cell
• 10 meq acid/hr.
• Gastric ---gt () vagus G cell
• 15 25 meq of acid/hr pH lt 2.0
• Intestinal
• Chyme enters the duodenum
• (-) gastric release
• Secretin, gastric inhibitory peptide, peptide YY
• ACID condition sterilized the area, except for
  HELICOBACTER PYLORI

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GASTRIC DISEASES

• Acid peptic Disease
• Neoplasm

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Acid peptic Disease

• Due to imbalance in the normal interplay between
  acid-pepsin and mucosal defense mechanism
• Types
• Acute Gastritis (erosive)
• Inflammation confined in the mucosa
• True Ulcers
• Extends through the mucosa

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Peptic ulcer

• Duodenal Ulcer
• Gastric Ulcer
• Duodenal ulcer gt gastric ulcer
• Female gt Male
• Duodenal ulcer is younger by 10 yrs
• Location
• Duodenal
• duodenal bulb
• Hyper-secretion of acid

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Peptic ulcer

• Location
• Gastric
• Type I - proximal antrum and body
• (disturbance in mucosal defense)
• Type II - arises secondary to duodenal
• ulcer w/ pyloric stenosis
• Type III - Prepyloric and pyloric channel
• - (hyper-secretion of acid)

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Peptic ulcer

• Pathogenesis
• For both Duodenal Gastric Ulcers
• Infection w/ H. pylori
• Decreases resistance of mucus layer from acid
  permeation (hydrophobicity)
• Increase acid secretion
• Slow duodenal emptying
• Reduced both duodenal and gastric bicarbonate
  secretion

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Peptic ulcer

• Pathogenesis
• Effects of NSAIDs
• Decreases Prostagladin
• Prostaglandin inhibits acid secretion,
  stimulates mucus and HCO3 secretion and mucosal
  blood flow
• Zollinger-Ellison Syndrome (1)
• Massive secretion of HCL due to ectopic gastrin
  production from non-beta islet cell tumor
  (gastrinoma)
• Associated w/ type I (MEN) PPP
• 20 multiple, 2/3 malignant, w/ slow growing
• Parietal cell mass is increased
• gt gastrin 3-6 x the normal

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Peptic ulcer

• For Duodenal
• Acid Hypersecretion
• More parietal and chief cells
• Genetic
• Due to release of tophic factors - gastrin
• Increase capacity of individual cell to secret
• Gastric Motility abnormality
• Impaired duodenal acid disposal
• Reduced basal and peak duodenal bicarbonate
  secretion and defect in mucus

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Peptic ulcer

• For Gastric Ulcer
• Reflux of Duodenal contents (pancreas and
  biliary)
• Gastritis -----gt Ulceration
• Pyloric sphincter dysfunction
• Cigarette smoking
• Increases duodeno-gastric reflux
• Decrease prostaglandin synthesis
• Decreases duodenal, gastric and pancreatic
  bicarbonate secretion
• Bile acids, lysolecithin and pancreatic
  secretions disturb surface mucus layer

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Clinical Manifestation

• Abdominal pain
• Due to irritation of afferent nerves w/in the
  ulcer by the acid or due to peristaltic waves
  passing through the ulcer
• Duodenal colicky or burning pain relieved w/
  food intake
• Gastric gnawing or burning usually during or
  after eating.
• N/V
• Weight loss
• Epigastric tenderness

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Diagnosis

1. UGIS (double contrast)
2. Endoscopy

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Treatment

• Medical
• Avoid the following
• Smoking
• Aspirin / NSAIDs
• Coffee (acid secretion)
• Alcohol (damage the mucosa)
• Mechanism of Pharmacologic Therapy
• Neutralize gastric secretion (HCL) ANTACID
• Inhibits Secretion of Acid
• H2 receptor antagonist CIMETIDINE,
• RANITIDINE, FAMOTIDINE

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Treatment

• Mechanism of Pharmacologic Therapy
• Inhibits Secretion of Acid
• Anticholinergic
• Inhibits acetylcholine
• Pirenzepine HCL
• H / K - ATPase inhibitor proton pump
• Benzimidazole selectively inhibits parietal cells
• Omeprazole, Lanzoprazole, Pantoprazole
• Protection of Gastric Mucosa
• Prostaglandin
• Methylated E2 analog inhibits gastric secretion,
  increases mucosal bld flow HCO3 mucosa
  secretion

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Treatment

• Mechanism of Pharmacologic Therapy
• Protection of Gastric Mucosa
• Sulfated disaccharide (sucralfate)
• Binds to protein in the ulcer as protective coat
• It can inhibits peptic activity
• Colloid bismuth
• Binds w/ protein against H. pylori

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Treatment

• Mechanism of Pharmacologic Therapy
• For eradication of H. pylori
• Bismuth based triple therapy
• Bismuth Tetracycline Metronidazole
• Proton pump inhibitor
• Omeprazole Amoxicillin/Clarithromycin
• metronidazole

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Treatment

• Surgical Treatment
• Indication
• Intractability
• Highly selective vagotomy
• Low septic complication, (-) dumping and diarrhea
• For gastric ulcer
• Total or subtotal gastrectomy w/ or w/o vagotomy

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Treatment

• Surgical Treatment
• Indication
• Hemorrhage s/sx
• Critically ill
• Endoscopy
• Surgery a. continue bleeding for more
  than 6 units
• b. recurrent bleeding after
  endoscopically controlled
• - pyloroduodenostomy HSV
• - pyloroduodenostomy vagotomy pyloroplasty

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Treatment

• Surgical Treatment
• Indication
• Perforation S/Sx
• Graham omental patch only for shock, perforation
  gt 48 hrs or other medical problem
• Vagotomy pyloroplasty HSV
• Vagotomy Gastrojejunostomy
• Obstruction S/Sx Saline loading test
• Vagotomy Antrectomy
• Vagotomy Gastroenterostomy

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Acute Gastritis (erosive)

• Stress erosions are usually multiple, small
  punctuate lesion in the proximal acid secreting
  portion of the stomach
• Clinical Settings
• Severe illness, trauma, burns (Cushing ulcer) or
  sepsis
• Due to (-) mucosal defense (ischemia)
• Drug and Chemical ingestion
• Aspirin / NSAIDs
• CNS trauma
• Increase gastrin ---gt elevated acid secretion
• Curling ulcer

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Acute Gastritis

• Pathogenesis
• Aspirin, bile salts (backflow), alcohol
• Mucosal ischemia
• Clinical manifestations
• Gastrointestinal bleeding
• Abdominal pain
• Diagnosis
• Endoscopy / radionuclide scanning / visceral
  angiography

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Acute Gastritis

• Treatment
• NPO
• NGT / Saline lavage
• Antacids / omeprazole / sucralfate
• Intra-arterial infusion of vasopressin
• Surgery --gt if 6-8 units over 24 hrs
• Mortality ---gt 40
• Near total gastrectomy
• Vagotomy pyloroplasty over sewing of bleeder
• Partial gastrectomy vagotomy

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Zollinger-Ellison Syndrome (Gastrinoma)

• Symptoms tends to be more severe, unrelenting and
  less responsive to therapy.
• Clinical Manifestation
• Pain
• Diarrhea
• Steatorrhea
• Diagnosis
• Acid secreting studies (50meq/hr)
• UGIS
• Radio-immuno assay for serum Gastrin level
• Diff a) Pernicious anemia
• b) Renal insufficiency
• c) Antral gastrin hyperplasia or
  hyperfunction
• CT scan and angiography to localize gastrinoma
• Venous sampling

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Gastric Neoplasm

• 90 malignant
• 95 adenocarcinoma
• 4 lymphoma
• 1 leiomyosarcoma (GIST-malignant
  gastrointestinal stromal tumors)
• Rare carcinoid, angiosarcoma, squamous cell CA.
• As metastatic lesion of --gt
• - colon/pancreas
• - melanoma/breast
• Malaysia, Chile, Iceland and JAPAN
• MaleFemale (21) more common twice in
• black than
  white
• 6 -7 decade of life if it occurs in
  young(30-40y/o) becomes more aggressive (linitis
  plastica or signet ring histology)
• Low socioeconomic

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Adenocarcinoma

• Etiology
• Diet - high in nitrates-----gtnitrites (bacteria
  bile salts)
• - pickled, salted or smoked food
• - fresh fruit vegetable and vit C E ---gt
  lowers
• H. pylori infection
• 3 fold increase risk
• Ebstein Barr virus
• Genetic factor
• Suppression of p53 (tumor suppression gene)
• over expression of COX-2

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Adenocarcinoma

• Etiology
• Cigarette smoking (alcohol (-) effect)
• Gastric polyp (epithelial, inflammatory,
  hamatomatous, heterotopic, hyperplastic
  adenoma) adenoma hyperplastic polyps can lead
  to CA.
• Chronic atrophic gastritis (CAG)
• Most common precursor of CA (intestinal type)
• H. pylori causes CAG

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Adenocarcinoma

• Etiology
• Intestinal metaplasia (H. pylori)
• Benign gastric ulcer
• It is now generally recognized that all gastric
  ulcers are cancer until proven otherwise
• Previous Gastric resection
• 10 yrs later near the stoma
• Others - Radiation exposure - Family hx
• - Pernicious anemia - Bld type A
• (1.2 risk)

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Gastric Neoplasm

• Pathology
• Gastric dysplasia ---gt precursor of gastric CA
• Early gastric cancer
• Limited to the mucosa and submucosa, regardless
  of LN status
• 70 are well differentiated
• Cure rate is 90

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• Pathology
• Macroscopic Subtypes
• Superficial spreading
• Polypoid (well differentiated)
• Fungating
• Ulceration
• Scirrhous (linitis plastica) infiltrates the
  entire thickness of the wall
• Leather bottle stomach
• Poor prognosis
• Usually undifferentiated
• Location of primary tumor
• 40 distal / 30 middle / 30 distal

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HISTOLOGY

• WHO Classification
• Adenocarcinoma
• Papillary adenocarcinoma
• Tubular adenocarcinoma
• Mucinous adenocarcinoma
• Signet-ring cell carcinoma
• Adenosquamous carcinoma
• Squamous cell CA
• Small cell CA
• Undifferentiated CA
• Others

• Lauren Classification
• Intestinal type (53)
• Diffuse type (33)
• Unclassified (14)
• Ming Classification
• Expanding type (67)
• Infiltrative type (33)

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Pathologic Staging (TNM)
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• Microscopic Subtypes
• Intestinal Type
• Diffuse Type

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• Histologic type
• Papillary
• Tubular
• Mucinous
• Signet ring
• Mode of spread
• Direct
• Lymphatic
• Hematologic
• Transcoelomic route

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• Clinical Manifestation
• Weight loss due to anorexia and early satiety is
  the most common symptoms
• Abdominal pain (not severe) common
• Nausea / vomiting
• Chronic occult blood loss is common
• GIT bleeding (5)
• Dysphagia (cardia involvement)

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• Clinical Manifestation
• Paraneoplastic syndromes ( Trousseaus syndrome
  thrombophlebitis acanthosis nigricans
  hyperpigmentation of axilla and groin peripheral
  neuropathy)
• Signs of distant metastasis
• Hepatomegally / ascites
• Krukenbergs tumor
• Blummers shelf (drop metastasis)
• Virchows node
• Sister Joseph node (pathognomonic of advances
  dse)

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• Diagnosis
• UGIS (double contrast)
• Endoscopy (Biopsy / Ultrasound)
• GOLD STANDARD
• Best pre-operative staging
• Needle aspiration of LN w/ ultrasound guidance
• Can even give preop neoadjuvant tx
• CT scan (intravenous and oral contrast)
• For pre-operative staging
• Whole body Positron Emission Tomography scanning
  (PET)
• Tumor cell preferentially accumulate
  positron-emitting 18F fluorodeoxyglucose.

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• TREATMENT
• SURGERY
• The only curative tx for gastric cancer
• Except
• Cant tolerate abdominal surgery
• Overwhelming metastasis
• Palliation is poor w/ non-resective operations
• GOAL resect all tumors, w/ negative margins
  (5cm) and adequate lymphadenectomy (need for RFS)
• Enbloc resection of adjacent organ is done if
  needed.

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• TREATMENT
• SURGERY
• Radical subtotal gastrectomy
• Standard operation for gastric cancer
• Organs resected
• Distal 75 of stomach
• 2 cm of duodenum
• Greater lesser omentum
• Ligation of R L gastric artery and
  gastroepiploic vesels
• Billroth II gastojejunostomy

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• TREATMENT
• SURGERY
• Radical subtotal gastrectomy
• Standard operation for gastric cancer
• If gastric remnant left is small (lt20) do
  Roux-en-Y reconstruction

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• Extent of lymphadenectomy
• N1 3 to 6 N2 1, 2, 7, 8 11 N3 9,
  10 12
• N1 nodes are w/in 3cm of the tumor
• N2 along hepatic splenic arteries
• N3 more distant nodes
• Agreed upon to avoid under staging of gastric
  CA, a minimum of 15 nodes should be resected w/
  the gastrectomy specimen.

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Adjuvant Treatment for Gastric Carcinoma

• Chemotherapy
• 5-fluorouracil, leucovorin, cisplatin,
  doxorubicin and methotrexate
• Can not prolong survival in unresectable,
  metastatic or recurrent diseases
• Radiation (4500cGy)
• Effective in palliation for pain and bleeding
• For stages II and III adenocarcinoma

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• Radical subtotal gastrectomy
• D1 resection (standard in USA)
• Removes tumor and N1
• D2 resection(standard in Asia)
• Gastrectomy and N1 and N2 removal
• Removes the peritoneal layer over the pancreas
  and anterior mesocolon
• Removes LN along hepatic splenic
• Splenectomy and distal pancreatectromy not
  routinely removed due to higher morbidity postop.

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Endoscopic Resection of Gastric Carcinoma

• Criteria
• Tumor lt 2cm in size
• Node negative
• Tumor confined on the mucosa
• Nodes metastasis is lt 1
• No mucosal ulceration
• No lymphatic invasions
• lt3cm tumor

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Screening of Gastric Cancer

• Patients at risk for gastric CA should undergo
  yearly endoscopy and biopsy
• Familial adenomatous polyposis
• Hereditary nonpolyposis colorectal cancer
• Gastric adenomas
• Menetriers disease
• Intestinal metaplasia or dysplasia
• Remote gastrectomy or gastrojejunostomy