college o
Stomach cancer
[DOCUMENT SUBTITLE]
[COMPANY NAME] | [COMPANY ADDRESS]
Content
 Introduction
 What's stomach
cancer?
 The stomach
 Parts of stomach
 Classification
 What causes stomach
cancer?
Stages of stomach
cancer
 How can I prevent
stomach cancer?
1
Introduction
Stomach cancer, also called gastric
cancer (GC), is the 15th most common
cancer in the United States. According
to the SEER fact sheet, the estimated
number of new stomach cancer cases
for 2015 was 24,590—which was also
expected to be 1.5% of all new cancer
cases—and the estimated number of
deaths from stomach cancer for 2015
was 10,720, or about 1.8% of all
cancer deaths (National Cancer
Institute, 2015b). Additionally, it was
estimated in 2012 that in the United
States there were nearly 77,000
people living with the disease. The
prevalence worldwide, however, is
much higher, for which it is estimated
to be the fourth leading cause of
2
cancer and the second-leading cause
of cancer deaths. In 2012 alone,
952,000 new cases were diagnosed
throughout the world (Gastric Cancer
Foundation, 2015; Torre et al., 2015;
World Cancer Research Fund
International, 2015).
Stomach cancer also has a high
mortality rate, largely owing to the fact
that it is often not diagnosed until it is
in a later stage. In the US, while the
numbers of both new cases and
deaths from GC have been falling over
the last few decades, death rates did
not change significantly over the years
2002-2012 (National Cancer Institute,
2015b). The five-year relative survival
rate, though, has increased to
approximately 29.3% currently from
14.3% in 1975 (Ibid.).
3
What Is Stomach Cancer?
Cancer starts when cells in the body begin
to grow out of control. Cells in nearly any
part of the body can become cancer, and
can then spread to other areas of the
body. To learn more about cancer and
how it starts and spreads, see What Is
Cancer?
Stomach cancer, also called gastric
cancer, begins when cells in the stomach
start to grow out of control
The stomach
To understand stomach cancer, it helps to
know about the normal structure and
function of the stomach.
The stomach is a sac-like organ that’s an
important part of the digestive system
4
After food is chewed and swallowed, it
enters the esophagus, a tube that carries
food through the throat and chest to the
stomach. The esophagus joins the
stomach at the gastroesophageal (GE)
junction, which is just beneath the
diaphragm (the thin sheet of breathing
muscle under the lungs).
The stomach then starts to digest the food
5
by secreting gastric juice. The food and
gastric juice are mixed and then emptied
into the first part of the small intestine
called the duodenum
Some people use the word 'stomach' to
refer to the belly area. The medical term
for this area is the abdomen. For instance,
some people with pain in this area would
say they have a 'stomach ache', when in
fact the pain could be coming from some
other organ in the area. Doctors would call
this symptom 'abdominal pain,' because
the stomach is only one of many organs in
the abdomen
Stomach cancer is different from other
cancers that can occur in the abdomen,
like cancer of the colon or rectum (large
intestine), liver, pancreas, or small
intestine. These cancers can have
different symptoms, different outlooks,
and different treatments.
6
Parts of the stomach
The stomach has 5 parts.
The first 3 parts make up the proximal
stomach:
 Cardia: the first part, which is closest to
the esophagus
 Fundus: the upper part of the stomach
next to the cardia
7
 Body (corpus): the main part of the
stomach, between the upper and lower
parts.
Some cells in these parts of the stomach
make acid and pepsin (a digestive
enzyme), which combine to make
the gastric juice that helps digest food.
They also make a protein called intrinsic
factor, which the body needs to absorb
vitamin B12.
The lower 2 parts make up the distal
stomach:


8
Antrum: the lower portion (near the
small intestine), where the food mixes
with gastric juice
Pylorus: the last part of the stomach,
which acts as a valve to control the
emptying of the stomach contents into
the small intestine

Other organs near the stomach include
the small intestine, colon, liver, spleen,
and pancreas.
The stomach wall has 5 layers
The innermost layer is the mucosa. This is
where stomach acid and digestive
enzymes are made. Most stomach
cancers start in this layer.
Next is a supporting layer called
the submucosa.
Outside of this is the muscularis propria, a
thick layer of muscle that helps move and
mix the stomach contents.
9
The outer 2 layers, the subserosa and the
outermost serosa, wrap the stomach.
The layers are important in
determining the stage (extent) of the
cancer, which can affect a person’s
treatment options and prognosis (outlook).
As a cancer grows from the mucosa into
deeper layers, the stage becomes more
advanced and treatment might need to be
more extensive.
Classification
Types of Stomach Cancer
1. Adenocarcinoma – About 90-95% of
all stomach cancers are of this type
and therefore the greatest availability
of stomach cancer samples will be for
this indication. Adenocarcinomas
develop from the stomach mucosa (its
innermost layer) that is composed of
glandular tissue. There are two main
types of gastric adenocarcinoma
10
a.
Intestinal type – closely associated
with dietary and environmental factors
such as a diet high in salt and H.
pylori infection. It is characterized by the
formation of gland-like structures, and its
pathogenesis is considered to be a “longterm multistep progression from chronic
gastritis to chronic atrophy to intestinal
metaplasia to dysplasia,” (Hudler, 2012) a
process that is sometimes called the
Correa pathway. It is dependent on
chronic inflammation.
B. Diffuse type – less common than the
intestinal type but more common in
younger patients. It can also arise in part
from H. pylori infection but without the
intermediate steps such as gastric atrophy
and intestinal metaplasia. Its histological
characterization is of poor differentiation
and a lack of glandular structures. The
prognosis is usually worse than with the
intestinal type
11
2. Lymphoma – Comprising about 4% of
all stomach cancers, lymphomas develop
in immune system tissue within the
stomach wall.
3. Others – Gastrointestinal stromal
tumor (GIST), Carcinoid tumors, and
other rare cancers can also develop in
the stomach.
What Causes Stomach Cancer?
Scientists don’t know exactly what
makes cancer cells start growing in the
stomach. But they do know a few things that
can raise your risk for the disease. One of
them is infection with common bacteria, H.
pylori, which causes ulcers. Inflammation in
your gut called gastritis, a certain type of longlasting anemia called pernicious anemia, and
12
growths in your stomach called polyps also
can make you more likely to get cancer.
Other things that seem to play a role in raising
the risk include












13
Smoking
Being overweight or obese
A diet high in smoked, pickled, or salty
foods
Drinking alcohol regularly
Stomach surgery for an ulcer
Type-A blood
Epstein-Barr virus infection
Certain genes
Working in coal, metal, timber, or rubber
industries
Exposure to asbestos
Family history of gastric cancer
Hereditary factors such as familial
adenomatous polyposis, hereditary nonpolyposis colorectal cancer (Lynch
syndrome), and Peutz-Jeghers syndrome
Just having indigestion or heartburn after a
meal doesn’t mean you have cancer. But if
you feel these symptoms a lot, talk to your
doctor. They can see if you have other risk
factors and test you to look for any
problems.
As stomach tumors grow, you may have more
serious symptoms, such as










14
Stomach pain
Blood in your stool
Vomiting
Weight loss for no reason
Trouble swallowing
Yellowish eyes or skin
Swelling in your stomach
Constipation or diarrhea
Weakness or feeling tired
Heartburn
Stages of Stomach Cancer
The stages of stomach cancer are
determined by combining information from
TNM staging into Stages I-IV and further
subdivided based on where exactly the
cancer has spread to



Stage 0 – The cancer has not grown past
the inner layer of cells lining the stomach;
this is its earliest stage.
Stage I – Cancer has formed in the
mucosa (the innermost layer of the
stomach wall). It may have spread further
into the submucosa or even the
muscularis propria. Spreading to one or
two lymph nodes may have occurred as
well.
Stage II – Cancer has advanced into the
submucosa and several lymph nodes; or
the muscularis propria and a few lymph
nodes; or it has advanced into the
subserosa or serosa, possibly in
combination with spreading into one or
15


two lymph nodes as well. Overall, the
cancer will have spread deeper into the
stomach wall and/or to more lymph nodes
than a stage I cancer.
Stage III – Cancer has spread into the
muscularis propria, serosa, or subserosa
as well as lymph nodes, or it has spread
to nearby organs and possibly lymph
nodes. Overall, the cancer will have
spread deeper into the stomach wall
and/or to more lymph nodes than a stage
II cancer.
Stage IV – Cancer has metastasized
(spread to distant parts of the body)
16
17
How Can I Prevent Stomach Cancer?
Treat stomach infections. If you have
ulcers from an H. pylori infection, get
treatment. Antibiotics can kill the bacteria,
and other drugs will heal the sores in the
lining of your stomach to cut your risk of
cancer.
Eat healthy. Get more fresh fruits and
vegetables on your plate every day. They’re
high in fiber and in some vitamins that can
lower your cancer risk. Avoid very salty,
pickled, cured, or smoked foods like hot dogs,
processed lunch meats, or smoked cheeses.
Keep your weight at a healthy level, too.
Being overweight or obese can also raise your
risk of the disease.
Don’t smoke. Your stomach cancer risk
doubles if you use tobacco.
Watch aspirin or NSAID use. If you take
daily aspirin to prevent heart problems or
NSAID drugs for arthritis, talk to your doctor
about how these drugs might affect your
stomach
18
19