Stomach cancer is also known as gastric cancer and occurs when cells grow abnormally in the stomach. Cancer can form anywhere in the stomach but it commonly occurs where the esophagus meets the stomach. This area is called the gastroesophageal junction. Cancer location is one of the considerations when deciding on treatment options and disease management.
Types of Stomach Cancer
- Adenocarcinoma is overwhelmingly the most common type of stomach cancer, accounting for 90-95% of diagnoses. Adenocarcinoma develops in the cells of the inner lining of the stomach called the mucosa and then spreads outward.
- Lymphoma starts in the immune system tissues located in the stomach wall.
- Carcinoid tumors don’t typically spread but develop in the hormone-creating cells of the stomach.
- Squamous cell carcinoma originates in the stomach lining which is made up of skin-like cells.
Other types of stomach cancer, such as small cell carcinoma, leiomyosarcoma, and gastrointestinal stromal tumors are extremely rare.
Symptoms
Stomach cancer often has no early symptoms making it hard to detect. Not all symptoms indicate stomach cancer is present but if multiple symptoms are experienced over time, a doctor should be consulted.
- Poor appetite and unwillingness to eat.
- Weight loss that is unintended and has no explanation.
- Anemia or low blood count that often leads to fatigue.
- Vomiting with or without blood.
- Blood in the stool or black stool indicating blood in the digestive tract.
- Abdominal pain and/or an uncomfortable feeling above the naval.
- Nausea that is unrelated to other conditions or illness.
- Stomach swelling indicates fluid collecting on the abdomen.
- Indigestion or heartburn that is frequent and long-lasting.
- Feeling full after eating a small meal and feeling bloated.
Causes and Risk Factors
Helicobacter pylori: A major cause of stomach cancer is believed to be the bacteria Helicobacter pylori. Long-term infection with H. pylori causes inflammation that has been linked to precancerous changes to the lining of the stomach. H. pylori infection is found at a higher rate in people who develop cancer of the stomach than people who do not develop cancer.
Diet: Eating large quantities of smoked foods, salted fish, meat and pickled foods, increases the risk of developing stomach cancer. The nitrates and nitrites found in these foods convert into compounds that have been shown to cause stomach cancer in scientific laboratories.
Tobacco: The risk of stomach cancer, particularly in the upper stomach near the esophagus, is doubled if a person uses tobacco.
Certain Occupations: Coal miners and workers in the rubber and metal industries have a higher risk of stomach cancer because of environmental exposure to dust, chemicals, and airborne fibers such as asbestos.
Family History: Having a first-degree relative diagnosed with stomach cancer increases the risk of gastric cancer, although the mechanism of the increased risk is still unclear.
Obesity: Being overweight may increase the risk of cancer in the upper part of the stomach near the esophagus.
Asbestos and Stomach Cancer
The International Agency for Research on Cancer classifies asbestos as belonging to Carcinogen Group 2A for gastric cancer. The association of gastric cancer and asbestos fiber exposure is well-known.
Asbestos fibers can be swallowed and deposited into the stomach. Some fibers are excreted through the digestive symptom within a few days. Remaining fibers may penetrate the cells that line the stomach or intestines. The accumulation of asbestos fibers over time may lead to stomach cancer.
Evidence suggests that there is no safe range of exposure to asbestos.
Individuals are affected by asbestos differently according to:
Dose: How much asbestos was involved in the exposure.
Duration: How long a person was exposed to asbestos.
Size: The chemical makeup, size, and shape of the asbestos fibers ingested or inhaled.
Treatment
Treatment for stomach cancer varies depending on where the cancer started and how far it has spread.
Surgery offers the only realistic chance for a cure and is often combined with other treatments.
Chemotherapy can be given before surgery to shrink the tumor and make surgery easier. Chemo may be given after surgery as well, to kill any cancer cells left behind and to keep the cancer from returning. Chemo may be used as the main treatment for stomach cancer that has spread to other organs.
Immunotherapy uses medicines that enable the natural immune system to find and destroy cancer cells. This can shrink some tumors and/or slow their growth.
Radiation Therapy uses high-energy particles to kill cancer cells in a specific location. Before surgery, radiation can be helpful to shrink the tumor and make surgery easier. Like chemotherapy, radiation therapy can be used after surgery to kill cancer cells left behind. In advanced stomach cancer cases, radiation can slow cancer growth and ease symptoms.
New and advanced stomach cancer treatments are continually being developed and improved. Clinical trials of newer treatments may benefit some patients.
Pain and symptom management is a critical component to any cancer treatment. Some treatments, while not able to shrink or destroy the cancer, can relieve pain and lessen symptoms.
Stomach Cancer Statistics
The American Cancer Society estimates that 27,600 cases of stomach cancer will be diagnosed in 2020, with 16,980 of those cases being men and 10,620 being women.
The average patient age at diagnosis is 68 years old, with 6 out of 10 people being 65 years or older.
The risk of developing stomach cancer is affected by many factors, in general a man’s chance of developing stomach cancer is 1 in 95 and a women’s risk is calculated at 1 in 154.
Cases of stomach cancer have decreased 1.5%, but it is still one of the leading causes of cancer-related deaths in the world.
It is estimated that over 11,000 people will die from stomach cancer in 2020.
The five-year survival rate for people with stomach cancer is 32%. This number reflects the difficulty in diagnosing stomach cancer early, before it has spread. The survival rate increases to 69% if diagnosis and treatment occur before the cancer has spread outside the stomach.
