Transcript Gastric Cancer Prevention

Gastric Cancer
Prevention
Luis S. Mon, M.D., F.A.C.S.
Carlos A. Perurena, M.D.
Gastric Cancer Prevention
• Drs. Mon and Perurena are proffesors
or Surgery at the University of
Panama´s Medical School. They can be
contacted at [email protected]
• Gastric Cancer is the fifth most
frequent cancer and the second most
lethal in the Republic of Panama.
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.
Gastric Cancer Prevention
•Biology
•Epidemiology
•Risk Factors
•Primary Prevention
•Secondary Prevention
Gastric Cancer Prevention:
Biology
• 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.
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.
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.
Gastric Cancer Prevention
Biology: Hystopathology
• Adenocarcinoma is considered
early when it´s confined to the
mucosa and sub-mucosa,
irrespective of lymph node
affection.
• Otherwise it’s called advanced.
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.
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.
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
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.
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.
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.
Gastric Cancer Prevention:
Chronic Atrophic Gastritis
• Chronic Atrophic Gastritis is
thought to be the initial step
in the development of most
Gastric Cancers.
Gastric Cancer Prevention:
Chronic Atrophic Gastritis
Chronic Atrophic Gastritis
has been shown to appear
in patients with:
1. Tobacco use.
2. H. pylori infection.
(cont.)
Gastric Cancer Prevention:
Chronic Atrophic Gastritis
3. Diets with high levels of
nitrites, nitrates, salt and
smoked foods.
4. Previous Gastric Surgery.
5. Pernicious Anemia.
Gastric Cancer Prevention:
Tobacco
• 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.
Gastric Cancer Prevention:
Tobacco
• Tobacco use decreases the
levels of Carotenoids and
Vitamin C which act as
protective agents against
this disease.
Gastric Cancer Prevention:
Tobacco
• Tobacco use is associated
with Helycobacter pylori
infection which in turn leads
to Atrophic Gastritis.
Gastric Cancer Prevention:
Tobacco
• Smoking cessation returns
the risk to that of the general
population after 20 years.
Gastric Cancer Prevention:
Helycobacter 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.
Gastric Cancer Prevention:
Helycobacter pylori
• In 1994 the World Health
Organization designated
H. pylori a Group 1 carcinogen
Gastric Cancer Prevention:
Dietary 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.
Gastric Cancer Prevention:
Dietary Factors
• Nitrates and nitrites found in
salted, smoked and dried foods
lead to atrophic Gastritis which
in turn leads to Gastric Cancer.
Gastric Cancer Prevention:
Genetic Factors
All of the following genetic
factors have been shown to
increase the risk of Gastric
Cancer.
Gastric Cancer Prevention:
Genetic Factors
• Blood type A.
• Hereditary non-polyposis
colorectal cancer.
• e-cadherin gene mutations.
• A first degree relative with
Gastric Cancer.
Gastric Cancer Prevention:
Genetic Factors
• Presently they are not subject
to preventive measures except
for prophylactic gastrectomy in
e-cadherin mutations.
Gastric Cancer Prevention:
Secondry 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.
Gastric Cancer Prevention:
Secondary Prevention
• In Japan gas-contrast Stomach
Fluorography is done in the
mass population.
(cont.)
Gastric Cancer Prevention:
Secondary Prevention
• Those considered abnormal
(about 13%) will undergo further
studies, including endoscopy
and biopsy.
Gastric Cancer Prevention:
Conclusions
The best primary
prevention strategies are:
Gastric Cancer Prevention:
Conclusions
• Smoking avoidance or
cessation.
• Diets rich in fruit, vegetables
and fiber.
• Avoidance of salted, smoked
and poorly preserved foods.
• Erradication of H. pylori.
Gastric Cancer Prevention:
Conclusions
• Mass screening is a
viable strategy in high
risk populations.