neo_gastric
stomach cancer
introduction
2nd most common cause of cancer-related death in the world
remains difficult to cure as most present late
14th most common cancer in Western cultures and ranks about 7th in cancer causes of mortality, and median age at Dx is around 70yrs, with 25% present with localized disease, 31% with regional disease, 32% with metastatic disease
40% of cancers develop in the lower part, 40% in the middle part, and 15% in the upper part
90-95% of all gastric malignancies are adenocarcinoma of the stomach
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2% are gastrointestinal stromal tumors
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1% are adenoacanthomas
1% are squamous cell carcinomas
risk factors
high prevalence in Japan, Andean regions of South America, and Eastern Europe
diet vs genetics
early environmental exposure, rather than genetic factors, appear to have a greater influence on risk
10% are familial (independent of H.pylori infection)
diffuse type – strongly correlated with mutations in E-cadherin gene, CDH1
risk for people carrying these rare mutations in the E-cadherin gene have 70% chance if male and 56% if female (and these woman also have 42% chance of lobular breast cancer
1)
hereditary syndromes:
HNPCC, FAP, Li-Fraumeni syndrome, Peutz-Jeghers syndrome, Cowdens syndrome
chronic Helicobacter pylori infection
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high salt or preserved meat (pickled or smoked) / nitrates intake
contamination of food by carcinogenic compounds arising from the decay of unrefrigerated meat products
hypochlorhydria (chronic atrophic gastritis, pernicious anaemia, partial gastrectomy)
⇒ decrease in luminal vitamin C, which is an antioxidant
⇒ increase in serum gastrin, which is a potent inducer of gastric epithelial cell proliferation
⇒ allows colonization of bacteria capable of converting dietary nitrates to mutagenic N-nitroso compounds
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gastric polyps
gastric ulcers
smoking
obesity - increases risk of gastric cardia cancers
blood group A patients are at 20% excess risk of cancer
Various immunodeficiency syndromes
Menetrier disease
reproductive hormones are thought to have a protective role (risk is lower in women)
Hereditary Diffuse Gastric Cancer
AD with very high penetrance giving lifetime risk of 40-67% in men and 60-83% in women
average age at Dx is 38yrs
affected women are also at increased risk of lobular breast cancer
clinical features
other late complications
gastric cancer can spread by direct invasion, via lymphatics, or hematogenously
pleural effusion
ascites
gastric outlet obstruction
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cachexia
Krukenberg tumor – metastatic tumor to the ovary
paraneoplastic syndromes:
investigations
gastroscopy and biopsy
CEA is elevated in about 50% of cases
CA 19-9 is elevated in about 20% of cases
CT abdo to assess extent of local disease and spread
neo_gastric.txt · Last modified: 2015/02/14 10:52 (external edit)