Gastric Polyps • 1. Metaplastic- due to H. pylori infection, responds to eradication treatment. • 2. Inflammatory polyps • 3.Fundic polyps- due to PPI drugs or as a part of FAP syndrome. • 4. Adenomas- about 10% become malignant • 5. Carcinoid tumours of stomach
Carcinoma of Stomach • Cancer with poor prognosis unless detected and treated in early stages • The only curative modality of treatment is surgical • Incidence- 40/ 100,000 per year. In Japan 70 • More common in males, elderly
Location • More common in distal stomach in patients from lower socio-economic background and proximal stomach in patients from upper socio- economic group • Carcinomas from body and distal stomach are often associated with H. pylori infection unlike proximal gastric or Gastroesophageal (GE) junction tumours
Etiology Multifactorial • H. pylori • Pernicious anemia & gastric atrophy • Gastric polyps- adenomas • Previous gastric surgeries • Smoking • Diet- high salt intake, deficient antioxidants, N-nitroso compounds • Obesity • Genetic.
Molecular Biology of gastric ca • Less well understood than colorectal carcinoma. • Intestinal type-50% of patients have mutation or heterozygosity in APC gene. 30% patients have beta catenin mutation. Loss of heterozygosity at bcl-2 gene(inhibition of apoptosis)
Diffuse type- 50% patients have E- cadherin mutation. Rarely mutations in APC gene. • Both intestinal and diffuse type- 15% may have microsatellite instability(MSI – HNPCC/ Lynch syndrome) which is a DNA replication error. 30% patients have inactivation of p53 gene. Overexpression of growth factor receptors- c-Met, k- Sam,c-ErB2. Overexpression of transforming growth factor alpha, epidermal growth factor(EGF), vascular endothelial growth factor(VEGF)
Pathology • Lauren classification- 1. Intestinal gastric carcinoma: polypoidaltumours. Arise from intestinal metaplasia. Better prognosis 2. Diffuse gastric carcinoma- diffuse infiltration of gastric wall without forming any localised lesions 3. Mixed type- • Early Gastric Carcinoma/ Advanced Gastric Ca
Early gastric carcinoma- malignant cell infiltration confined to mucosa and submucosa with or without lymph node metastasis. Protruding , superficial, excavated ( Japanese). Curable. 5 year survival is upto 90%. In Japan 1/3 of stomach cancers are early gastric carcinomas.
Advanced gastric cancers- malignant cells infiltrate muscularis layer. Bormann’s classification- Type I, II, III, IV.
Spread -Distant spread is not common before local lymph node involvement. • Direct spread- muscularis layer, serosa, adjacent organs like pancreas, colon, liver. • Lymphatic spread- by permeation and embolisation. Supraclavicular lymph node involvement in advanced stage- Troisier’s sign. • Haematogenous- liver, lung, bone.
Transperitoneal spread- rectovesical/ rectovaginal pouch deposit- Blumer’s shelf. Ovaries in premenopausal women- Krukenberg’stumour. Umbilical deposits- Sister Mary Joseph nodules. Ascites.
Clinical Features • Early gastric carcinoma- nonspecific symptoms, dyspepsia. May be detected during gastroscopy for screening (Japan) or dyspepsia. • Exclude gastric cancer in all patients before PPI.
Advanced stage- • Early satiety, bloating, abdominal distention, vomiting, haematemesis, melaena or iron deficiency anemia • Obstruction to GE junction causes dysphagia, epigastric fullness, vomiting • Pyloric obstruction- features of gastric outlet obstruction. Alkalosis is mild or absent • Thrombophlebitis (Trousseau’s sign), deep vein thrombosis.
Management • Gastroscopy, biopsy • Hb , PCV • Serum electrolytes • Blood urea , serum creatinine • USG abdomen • CT scan abdomen • PET- CT scan • Chest X ray • Pre operative laparoscopy
If not operable- palliative procedures- palliative resection, palliative gastro-jejunostomy, Devine’s gastric exclusion, endoscopic stenting across the gastric tumour.
Chemotherapy- pre-op chemotherapy is effective. • Combination of Epirubicin, Cisplatinum, 5 Fluorouracil/ Capacitabine • Taxotere, Oxaliplatin • Trastuzumab( Herceptin)- in advanced, metastatic Her 2 receptor positive gastric cancers • Radiotherapy has no significant role.
Prognosis • Japan- 5 year survival is 50-70%. • West- 25-30%