Gastric Cancer Prevention

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Gastric Cancer Prevention

• Luis S. Mon, M.D., F.A.C.S.
• Carlos A. Perurena,
  M.D.

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Gastric Cancer Prevention

• Drs. Mon and Perurena are proffesors or Surgery
  at the University of Panamas Medical School.
  They can be contacted at monymon_at_cwpanama.net
• Gastric Cancer is the fifth most frequent cancer
  and the second most lethal in the Republic of
  Panama.

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Gastric Cancer Prevention

• Learning Objectives
• 1. State the basic biological characteristics of
  Adenocarcinoma of the Stomach.
• 2. Describe the principal epidemiological
  features of the disease.
• 3. Recognize the most probable risk factors for
  the disease.
• Performance Objectives
• 1. Propose specific strategies for Gastric Cancer
  primary prevention.
• 2. Propose strategies for Gastric Cancer
  secondary prevention.

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Gastric Cancer Prevention

• Biology
• Epidemiology
• Risk Factors
• Primary Prevention
• Secondary Prevention

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Gastric Cancer PreventionBiology

• There are several Hystological types of Gastric
  Cancer of which adenocarcinoma is by far the most
  frequent.
• Sarcomas and Lymphomas can also occur.
• This presentation refers basically to
  adenocarcinoma.

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Gastric Cancer Prevention Biology Hystopathology

• Two types of adenocarcinoma are recognized
• 1. Intestinal resembles colon cancer, can be
  polypoid or ulcerated, occurs usually in the
  distal stomach and has a prolonged
  pre-cancerous phase.

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Gastric Cancer Prevention Biology Hystopathology

• 2. Difusse Extends widely with no distinct
  margins and the glandular structure is rarely
  present.
• Patients tend to be younger and have a worst
  prognosis.

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Gastric Cancer Prevention Biology Hystopathology

• Adenocarcinoma is considered early when its
  confined to the mucosa and sub-mucosa,
  irrespective of lymph node affection.
• Otherwise its called advanced.

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Gastric Cancer Prevention Epidemiology

• Infrequent before 40 years of age.
• Twice as frequent in men than in women.
• Leading cause of death from cancer worldwide.

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Gastric Cancer Prevention Epidemiology

• Highest incidence in Japan, South America and
  Eastern Europe.
• Adjusted rate worldwide is 15.62 per 100 000
• Adjusted rate for Latin America is variable.

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Gastric Cancer Prevention Epidemiology

• In Costa Rica the incidence rate for men is 51.5
  and 28.7 for women.
• In Panama ( a country that borders Costa Rica)
  the global rate is 11.5

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Gastric Cancer Prevention Epidemiology

• In the United States the incidence has been
  decreasing and unexplainedly the cancer has
  migrated proximally.
• Gastro-esophageal lesions are
• more frequent than antral lesions.

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Gastric Cancer Risk Factors and Primary
Prevention

• Gastric Cancer is a very common
  disease that carries a high
  mortality.
• The diagnosis in early phases, when better
  results should be expected, is difficult due to
  the unspecifity of early symptoms.

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Gastric Cancer Risk Factors and Primary
Prevention

• Recognition of risk factors and application of
  strategies directed towards their elimination are
  of paramount importance.
• We will discuss the most probable and convincing
  risk factors related to this disease.

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Gastric Cancer PreventionChronic Atrophic
Gastritis

• Chronic Atrophic Gastritis is thought to be the
  initial step in the development of most Gastric
  Cancers.

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Gastric Cancer PreventionChronic Atrophic
Gastritis

• Chronic Atrophic Gastritis has
  been shown to appear in patients with
• 1. Tobacco use.
• 2. H. pylori infection.
• 
  (cont.)

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Gastric Cancer PreventionChronic Atrophic
Gastritis

• 3. Diets with high levels of nitrites, nitrates,
  salt and smoked foods.
• 4. Previous Gastric Surgery.
• 5. Pernicious Anemia.

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Gastric Cancer PreventionTobacco

• Smoking increases the risk of Gastric Cancer by
  50 to 60
• It is estimated that smoking tobacco is
  responsible for 11 of all Stomach Cancers
  worldwide.

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Gastric Cancer PreventionTobacco

• Tobacco use decreases the levels of Carotenoids
  and Vitamin C which act as protective agents
  against this disease.

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Gastric Cancer PreventionTobacco

• Tobacco use is associated with Helycobacter
  pylori infection which in turn leads to Atrophic
  Gastritis.

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Gastric Cancer PreventionTobacco

• Smoking cessation returns the risk to that of the
  general population after 20 years.

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Gastric Cancer PreventionHelycobacter pylori

• H. pylori is associated with a two to sixfold
  increase in the risk of developing Gastric
  Cancer.
• Many believe that genetic and environmental
  factors also need to be present for H. pylori to
  cause cancer.

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Gastric Cancer PreventionHelycobacter pylori

• In 1994 the World Health Organization designated
• H. pylori a Group 1 carcinogen

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Gastric Cancer PreventionDietary Factors

• Consumption of fruit, vegetables and fiber has
  shown, in the majority of controled studies
  published, a protective effect against Gastric
  Cancer.
• This effect is probably due to Vitamin C or
  carotenes.

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Gastric Cancer PreventionDietary Factors

• Nitrates and nitrites found in salted, smoked and
  dried foods lead to atrophic Gastritis which in
  turn leads to Gastric Cancer.

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Gastric Cancer PreventionGenetic Factors

• All of the following genetic factors have
  been shown to increase the risk of Gastric
  Cancer.

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Gastric Cancer PreventionGenetic Factors

• Blood type A.
• Hereditary non-polyposis colorectal cancer.
• e-cadherin gene mutations.
• A first degree relative with Gastric Cancer.

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Gastric Cancer PreventionGenetic Factors

• Presently they are not subject to preventive
  measures except for prophylactic gastrectomy in
  e-cadherin mutations.

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Gastric Cancer PreventionSecondry Prevention

• Secondary prevention is the early detection of
  cancer through screening.
• This is done in populations where the disease is
  a major health problem.
• Examples of this approach can be found in Japan
  and Costa Rica.

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Gastric Cancer PreventionSecondary Prevention

• In Japan gas-contrast Stomach Fluorography is
  done in the mass population.
• 
  (cont.)

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Gastric Cancer PreventionSecondary Prevention

• Those considered abnormal (about 13) will
  undergo further studies, including endoscopy and
  biopsy.

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Gastric Cancer PreventionConclusions

• The best primary prevention strategies are

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Gastric Cancer PreventionConclusions

• Smoking avoidance or cessation.
• Diets rich in fruit, vegetables and fiber.
• Avoidance of salted, smoked and poorly preserved
  foods.
• Erradication of H. pylori.

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Gastric Cancer PreventionConclusions

• Mass screening is a viable strategy in high risk
  populations.