Stomach cancer, also known as gastric cancer, develops in the tissues lining the stomach. As it progresses, cancer cells can grow into the stomach wall and spread to other parts of the body, including nearby lymph nodes, the liver, the lungs, the pancreas and the ovaries. Stomach cancer is an aggressive disease, but it can be treated and even cured if caught early. Understanding the symptoms, causes and risk factors can help people identify stomach cancer in its early stages when it is most treatable.
Signs and Symptoms
Some common signs and symptoms of stomach cancer include:
– Fatigue
– Loss of appetite or feeling full after eating little
– Heartburn or indigestion
– Nausea
– Vomiting, with or without blood
– Stomach pain or cramps
– Feeling bloated after eating
– Unexplained weight loss
– Weakness and fatigue
– Vomiting blood or coffee ground-like material
– Black, tarry stools
Many of these symptoms can also be caused by other medical conditions. However, people who experience any of these symptoms persistently should see their doctor for evaluation. Prompt evaluation is especially important for those who are at higher risk for stomach cancer.
Risk Factors
Some factors that can increase risk of developing stomach cancer include:
– Older age – The risk increases after age 50
– Male gender – Stomach cancer is about twice as common in men as women
– Family history – Having a first-degree relative (parent, sibling or child) with stomach cancer increases risk
– Helicobacter pylori infection – This is a bacteria that causes stomach inflammation and ulcers
– Diet high in smoked or salted foods and low in fruits and vegetables
– Tobacco use – Smoking increases stomach cancer risk
– Previous stomach surgery
– Blood type A
– Chronic atrophic gastritis – Long-term inflammation of the stomach lining
– Pernicious anemia – Lowered ability to absorb vitamin B12
– Obesity
Diagnosis
If signs and symptoms indicate stomach cancer, the doctor will take a complete medical history and perform a physical exam. They may also order the following tests to make an accurate diagnosis:
– Endoscopy – A thin, lighted tube with a camera is threaded down the throat to examine the inside of the esophagus, stomach and first part of the small intestine. Biopsies can be taken of any abnormal areas.
– Upper GI series – The patient swallows a chalky liquid called barium which coats the lining of the esophagus, stomach and small intestine. X-ray images are taken to highlight any abnormal areas.
– CT scan – A computed tomography (CT) scan of the abdomen and pelvis creates cross-sectional images that can show the spread of cancer to lymph nodes and distant organs. A CT scan with intravenous contrast is often used to visualize the stomach wall.
– PET scan – Positron emission tomography (PET) uses a radioactive tracer to detect cancer cells throughout the body. It is sometimes combined with a CT scan.
– Laparoscopy – In this minimally invasive surgery, a thin, lighted tube with a camera is inserted through a small incision to examine the abdominal area for cancer spread.
If cancer is confirmed through these tests, additional imaging scans may be ordered to determine the cancer’s stage. Blood tests, biopsies and more invasive surgeries may also be required for staging purposes.
Stages of Stomach Cancer
Staging describes how far stomach cancer has progressed. It is based on:
– Size of the tumor
– How deeply it has grown into stomach or nearby structures
– Whether it has spread to lymph nodes or distant sites
Knowing the stage helps doctors determine the best treatment approach. Stomach cancer stages are:
Stage 0 – Cancer is only in the innermost stomach lining. Also called carcinoma in situ, it has not grown beyond the mucosa.
Stage 1 – The cancer has grown beyond the inner layer into the next layers of the stomach wall, but it has not spread to lymph nodes or other organs.
Stage 2 – The cancer has spread beyond the stomach to nearby tissues, but not to lymph nodes.
Stage 3 – The cancer has invaded further into stomach wall layers, lymph nodes, and/or nearby organs like the liver, colon, or pancreas. There are substages 3A, 3B and 3C.
Stage 4 – The cancer has metastasized, or spread to distant parts of the body beyond the nearby lymph nodes.
Types of Stomach Cancer
Stomach cancers are classified by the type of cells they develop from:
Adenocarcinoma – Develops from the cells that form the innermost lining of the stomach. Accounts for over 90% of stomach cancers.
Lymphoma – Starts in immune system cells present in stomach wall. Represents up to 4% of stomach cancers.
Gastrointestinal stromal tumor (GIST) – Begins in interstitial cells of Cajal, which are cells in the wall of the digestive tract that control motor function. Rare tumor representing 1% of stomach cancers.
Carcinoid tumor – Originates from hormone-producing neuroendocrine cells. These rare, slow-growing tumors make up less than 3% of stomach cancers.
Appearance and Color
The most common type of stomach cancer, adenocarcinoma, typically develops in the mucus-producing glandular cells lining the stomach. As these cancer cells multiply, they form a mass or lesion that can vary greatly in appearance.
Some key characteristics that affect the visual presentation of stomach adenocarcinomas:
– Ulceration – Cancers that ulcerate through the stomach lining often appear as a crater-like lesion with a raised, jagged border. The base may be red or pale.
– Polypoid growth – Some tumors form an elevated lump or mound on the inner stomach surface, resembling a polyp. Larger polypoid masses can obstruct the stomach outlet.
– Diffuse thickening – Widespread cancer cell infiltration results in diffuse wall thickening, giving the stomach a rigid, leather bottle-like appearance.
– Color – The cancer’s color depends on whether the lesion is ulcerated or intact. Ulcers often have a pale base with redness at the margins. Intact masses are frequently white, pale or pink, sometimes with surface bleeding.
Location in the Stomach
Where stomach cancer originates and grows affects its presentation and symptoms:
Proximal stomach (cardia) – Cancers in the top portion near the esophagus may grow to obstruct the opening, causing abdominal fullness and vomiting.
Body (corpus) – Tumors in the main part of the stomach can grow very large before producing symptoms. Weight loss is often the first sign.
Distal stomach (antrum) – Cancers in the lower end near the intestines frequently spread to surrounding tissues early on. Symptoms may include abdominal pain.
Diffuse – Widespread tumor distribution involving multiple stomach regions causes thickening of stomach walls that diminishes food intake.
Metastasis and Spread
Stomach cancers tend to spread to the:
– Lymph nodes around the stomach
– Liver
– Lungs
– Bones
– Peritoneal cavity (abdominal lining)
When cancer metastasizes, or spreads, to other organs, tumors form as masses of abnormal cancer cells. These metastases may be found during imaging scans or seen during surgical procedures. Their appearance depends on factors like:
– Location
– Size
– Stage of growth
Metastases in the liver, for example, may appear as solitary or multiple tumor masses that are firm or hard in texture and pale yellow. Lung metastases tend to present as round nodules of varying sizes, while bone metastases appear as painful lesions. Peritoneal implants are studded tumor nodules on the lining of the abdomen.
Microscopic Appearance
Under the microscope, a stomach adenocarcinoma exhibits certain characteristic features:
– Irregular, crowded glands in abnormal patterns
– Variably sized nuclei
– Loss of normal architecture
– Abundant mitotic figures indicating uncontrolled cell growth
– Invasion into muscularis layers of the stomach
– Lymphovascular invasion if metastasizing
These microscopic findings help pathologists determine the tumor grade, which describes how closely cancer cells resemble normal cells. Higher grade indicates more abnormality.
Treatment Options
Treatment options for stomach cancer include:
| Treatment Type | Description |
|---|---|
| Surgery | Removes part or all of the stomach and nearby lymph nodes. Includes subtotal gastrectomy or total gastrectomy. |
| Chemotherapy | Drugs like fluorouracil, doxorubicin, and cisplatin are given to kill cancer cells. |
| Radiation | High energy beams are directed at cancer sites to destroy tumor cells and shrink large cancers before surgery. |
| Immunotherapy | Drugs prompt the immune system to attack and destroy cancer cells throughout the body. |
| Targeted therapy | Drugs and other substances specifically target and block molecular pathways that enable cancer growth. |
Treatment plans are tailored for each patient based on the cancer’s location, stage, and unique characteristics. Combination therapies are often used to enhance effectiveness.
Prognosis and Survival Rates
The prognosis for stomach cancer depends heavily on when it is diagnosed. Survival rates are based on how many people live a designated amount of time after diagnosis:
5-year relative survival rate for all stages: ~31%
5-year stage-specific survival rates:
– Stage 0 – Higher than 95%
– Stage 1A – 71%
– Stage 1B – 57%
– Stage 2A – 46%
– Stage 2B – 33%
– Stage 3A – 20%
– Stage 3B – 14%
– Stage 4 – Less than 5%
Survival is poorer for larger, more advanced cancers. Early diagnosis and prompt treatment provide the best hope for survival.
Prevention
While many causes of stomach cancer are not controllable, certain lifestyle measures may help lower risk:
– Avoiding tobacco use
– Eating a diet high in fruits and vegetables
– Reducing intake of preserved, smoked, salted and nitrate-rich foods
– Treating H. pylori infection if present
– Maintaining a healthy weight
People with family histories of stomach cancer should discuss screening options with their doctor that may help detect cancer at earlier stages.
Conclusion
Stomach cancer presents in diverse ways based on factors like tumor location, stage, and cancer type. While ulcerative lesions with raised borders are most common, some adenocarcinomas form polypoid masses or lead to diffuse wall thickening. Metastases to distant sites also vary in appearance. Microscopically, tumors exhibit disorganized glands, aberrant nuclei, and invasion beyond the stomach lining. Though survival rates are relatively low, combating risk factors and pursuing early screening in high-risk groups can improve outcomes for this aggressive cancer. Awareness of stomach cancer signs and prompt evaluation remain key to obtaining treatment at the earliest and most survivable stages.