Cancer occurs when cells in the body begin to grow uncontrollably. This can happen in almost any part of the body, and these cancerous cells can spread to other regions. When this abnormal growth starts in the stomach, it is referred to as stomach cancer, or gastric cancer.
Development of Stomach Cancer
Stomach cancer generally progresses gradually over several years. Prior to the development of a full-blown cancer, there are often pre-cancerous changes in the stomach’s inner lining (mucosa). These early changes are usually symptomless and can go unnoticed.
Cancers that develop in various parts of the stomach can lead to different symptoms and outcomes. The tumor’s location within the stomach can also influence the treatment approach. For instance, cancers that originate near or grow into the GE junction are often treated and staged similarly to esophageal cancers. (For additional details, refer to Esophageal Cancer.)
Types of Stomach Cancer
Adenocarcinomas
A vast majority of stomach cancers (approximately 90% to 95%) are adenocarcinomas, which arise from the glandular cells in the stomach’s mucosa (the innermost lining).
If diagnosed with stomach cancer (also known as gastric cancer), it is most likely to be an adenocarcinoma. The following details and information focus on this specific type of cancer.
Stomach adenocarcinomas are categorized into two primary types:
- Intestinal type: This type typically has a slightly better outlook (prognosis). The cancer cells often exhibit specific gene alterations that may respond to targeted drug therapies.
- Diffuse type: Characterized by its rapid spread, this type is less common than the intestinal type and is generally more challenging to treat.
Other Stomach Cancer Types
- Gastrointestinal Stromal Tumors (GISTs):
These rare tumors originate from early forms of cells within the stomach wall known as interstitial cells of Cajal. Some GISTs have a higher likelihood of spreading to other body parts compared to others. While GISTs can develop in various areas of the digestive system, they most commonly begin in the stomach. For further details, refer to Gastrointestinal Stromal Tumor (GIST). - Neuroendocrine Tumors (Including Carcinoids):
Neuroendocrine tumors (NETs) arise from cells in the stomach (or other areas of the digestive system) that share characteristics with both nerve cells and hormone-producing (endocrine) cells. Most NETs grow slowly and generally do not spread to other organs, although some can spread more rapidly. More information is available in Gastrointestinal Neuroendocrine (Carcinoid) Tumors. - Lymphomas:
These cancers develop in lymphocytes, a type of immune system cell. While lymphomas typically originate in other body parts, some can start in the stomach wall. The treatment and prognosis for these cancers vary depending on the lymphoma type and other factors. Additional information can be found in Non-Hodgkin Lymphoma.
Who is at Risk for Stomach Cancer?
Stomach cancer can affect anyone, but certain factors can elevate your risk. You may have a higher likelihood of developing stomach cancer if:
- You are 65 years old or older.
- You were assigned male at birth.
- Your ethnic background is East Asian, South or Central American, or Eastern European.
Risk Factors
A risk factor is anything that increases the likelihood of developing a disease like cancer. Various cancers have different risk factors. Some of these, such as smoking, can be modified, while others, like age or family history, cannot be changed.
However, having one or more risk factors doesn’t guarantee that you’ll develop the disease. Many individuals with multiple risk factors never develop cancer, while some people with few or no known risk factors do.
Scientists have identified several factors that can increase the risk of stomach cancer. Some of these are within your control, while others are not.
- Gender: Stomach cancer is more prevalent in men than in women.
- Age: While stomach cancer can affect younger people, the risk increases with age. Most cases are diagnosed in individuals in their 60s, 70s, or 80s.
- Ethnicity: In the U.S., stomach cancer is more common among Hispanic Americans, African Americans, Native Americans, Asian Americans, and Pacific Islanders compared to non-Hispanic White people.
- Geographical Location: Globally, stomach cancer is more frequent in East Asia, Eastern Europe, and South and Central America, while it’s less common in Africa and North America.
- Helicobacter pylori Infection: Infection with Helicobacter pylori (H. pylori) bacteria is a significant cause of stomach cancer, particularly in the lower part of the stomach. Long-term infection can lead to atrophic gastritis and other pre-cancerous changes in the stomach lining. Although many people carry H. pylori, not everyone will develop stomach cancer.
- Weight: Being overweight or obese is associated with a higher risk of cancers in the upper part of the stomach, near the esophagus.
- Diet: Diets rich in salted foods, such as salted fish and meat and pickled vegetables, increase the risk of stomach cancer. Regular consumption of processed, grilled, or charcoaled meats also appears to raise the risk of non-cardia stomach cancers. Conversely, a diet low in fruits increases the risk, while a diet high in fresh fruits (especially citrus fruits) and raw vegetables may lower it.
- Alcohol Use: Alcohol consumption likely raises the risk of stomach cancer, especially for those who drink three or more alcoholic beverages per day.
- Smoking: Tobacco use doubles the risk of stomach cancer, particularly cancers in the upper part of the stomach near the esophagus.
- Previous Stomach Surgery: People who have had part of their stomach removed to treat non-cancerous conditions like ulcers are more likely to develop stomach cancer, possibly due to reduced acid production and the presence of more harmful bacteria. These cancers usually develop many years after the surgery.
- Certain Types of Stomach Polyps: While most stomach polyps (such as hyperplastic or inflammatory polyps) don’t significantly increase cancer risk, adenomatous polyps (adenomas) can sometimes turn into cancer.
- Pernicious Anemia: This condition, caused by a deficiency in intrinsic factor (IF), which is necessary for vitamin B12 absorption, increases the risk of stomach cancer.
- Menetrier Disease (Hypertrophic Gastropathy): This rare condition, characterized by excessive growth of the stomach lining and low stomach acid levels, may increase the risk of stomach cancer, although the exact risk is not well known.
- Inherited Cancer Syndromes: Certain inherited gene mutations can increase the risk of stomach cancer, though these syndromes account for a small percentage of stomach cancer cases globally.
- Hereditary Diffuse Gastric Cancer (HDGC): This rare syndrome significantly increases the lifetime risk of stomach cancer, with up to 70% of affected individuals developing the disease. Women with HDGC also have an increased risk of invasive lobular breast cancer. The syndrome is most commonly linked to mutations in the CDH1 gene.
- Lynch Syndrome (Hereditary Non-Polyposis Colorectal Cancer, or HNPCC): This inherited genetic disorder increases the risk of colorectal and stomach cancers, among others. It is caused by mutations in mismatch repair (MMR) genes like MLH1 or MSH2, which normally help repair damaged DNA.
- Familial Adenomatous Polyposis (FAP): This syndrome leads to the development of numerous polyps in the colon, stomach, and intestines, starting at an early age. While FAP carries a high risk of colorectal cancer, it also slightly increases the risk of stomach cancer. FAP is caused by mutations in the APC gene.
- Gastric Adenoma and Proximal Polyposis of the Stomach (GAPPS): This rare condition, caused by a mutation in a specific part of the APC gene, results in the development of numerous stomach polyps and an increased risk of stomach cancer.
- Li-Fraumeni Syndrome: This syndrome, caused by a mutation in the TP53 gene, increases the risk of several types of cancer, including stomach cancer at a relatively young age.
- Peutz-Jeghers Syndrome (PJS): This condition causes polyps in the stomach, intestines, and other areas, including the nose, airways, and bladder. People with PJS also develop dark freckle-like spots on the lips, inner cheeks, and other areas. The syndrome increases the risk of several cancers, including those of the colon, pancreas, stomach, and breast. PJS is caused by mutations in the STK11 gene.
- Family History: Having first-degree relatives (parents, siblings, or children) with stomach cancer increases your risk, even if you don’t have one of the inherited cancer syndromes mentioned above. However, most people who develop stomach cancer do not have a family history of the disease.
- Common Variable Immune Deficiency (CVID): Individuals with CVID have a weakened immune system that doesn’t produce enough antibodies, leading to frequent infections, atrophic gastritis, pernicious anemia, and an increased risk of gastric lymphoma and stomach cancer.
- Epstein-Barr Virus (EBV) Infection: EBV, which causes mononucleosis (mono), has been linked to several cancers, including nasopharyngeal cancer and some lymphomas. EBV is also found in 5% to 10% of stomach cancer cases, although its role in causing stomach cancer is not yet clear. Stomach cancers associated with EBV tend to grow more slowly and are less likely to spread.
- Certain Occupations: Workers in industries such as coal, metal, and rubber seem to have a higher risk of stomach cancer.
- Blood Type A: For reasons that are not fully understood, people with blood type A have a higher risk of developing stomach cancer.
Causes of Gastric Cancer
The precise cause of stomach cancer remains uncertain, but several factors have been linked to its development, particularly those related to diet and lifestyle. A diet rich in smoked, salted foods, and processed meats, coupled with low vegetable intake, can increase the risk of developing stomach cancer. Additionally, habits like alcohol consumption and smoking are known to be contributing factors. Infection with Helicobacter pylori, a bacterium that invades the stomach lining, also plays a role in the onset of this cancer.
Certain non-cancerous stomach conditions, such as ulcers or abnormal cell growth in the stomach lining, can sometimes precede the development of cancer. Furthermore, genetic predispositions can elevate the risk of stomach cancer.
However, it’s important to note that stomach cancer can still occur without any identifiable risk factors or conditions.
Symptoms of Gastric Cancer
In its early stages, stomach cancer often doesn’t cause noticeable symptoms. Some signs, such as a feeling of fullness after eating a small amount, mild abdominal discomfort, and fatigue, are common and may resemble symptoms of less serious health issues.
However, certain symptoms are more indicative of stomach cancer. If you experience any of the following symptoms for more than two weeks, it is crucial to consult a gastroenterologist:
- Unexplained weight loss
- Severe abdominal pain
- Nausea and vomiting
- Loss of appetite
- Vomiting blood
- Tarry, dark-colored stools
- Difficulty or pain when swallowing
Diagnosing Stomach Cancer
When you visit a gastroenterologist, they will begin by reviewing your medical history, conducting a thorough physical examination, and requesting blood and stool samples. These tests provide crucial information and guide further medical decisions. Your doctor may also order imaging tests, including:
- CT (Computed Tomography) scans
- PET (Positron Emission Tomography) scans
- MRI (Magnetic Resonance Imaging)
- Upper gastrointestinal endoscopy (EGD)
Additional diagnostic procedures include endoscopy with biopsy and endoscopic ultrasound.
Endoscopy with Biopsy
Endoscopy is a highly reliable and accurate method for diagnosing gastrointestinal conditions, particularly those involving the inner lining of the stomach and small intestines. With advanced endoscopic techniques, stomach cancer can be detected earlier, making treatment more effective.
During an endoscopy:
- You will lie on your left side.
- Anesthesia will be administered to ensure you are relaxed or asleep throughout the procedure.
- The doctor will guide a thin, lighted tube with a small camera (endoscope) through your mouth, down your throat, and into your stomach.
- The endoscope provides a clear view of the inner lining of your stomach, esophagus, and parts of the small intestine.
- If necessary, your doctor will perform a biopsy, removing a small tissue sample for laboratory testing. The biopsy results will help confirm a diagnosis.
After diagnosis, a follow-up endoscopy may be performed to determine the extent of the cancer, aiding in the planning of treatment and follow-up care.
Endoscopic Ultrasound
This procedure combines the endoscope with ultrasound, which uses sound waves to generate detailed images of your digestive tract. It is particularly useful for examining the middle and outer layers beyond the stomach’s inner lining. This test helps determine the depth of the tumor and whether it has spread to other areas.
How is Stomach Cancer Treated?
Treatment for stomach cancer varies based on the extent of the disease, your overall health, and your personal preferences. Typically, a multidisciplinary care team will guide your treatment. This team may include your primary care provider, an oncologist, and a gastroenterologist, who will discuss the best options for your situation.
Surgical Options:
The choice of surgery depends on how far the cancer has spread:
- Upper Endoscopy: If the cancer is in its early stages and confined to the superficial layers of the stomach, it can be removed via an upper endoscopy. In this procedure, a gastroenterologist performs either endoscopic submucosal dissection or endoscopic mucosal resection to remove the tumor through the mouth.
- Gastrectomy: If the cancer has invaded deeper layers of the stomach, surgery to remove part or all of the stomach may be necessary. A subtotal gastrectomy removes only the cancerous portion, while a total gastrectomy involves removing the entire stomach. After a total gastrectomy, the esophagus is connected directly to the small intestine to allow you to eat.
Other Treatments:
Several other treatments aim to destroy cancer cells directly:
- Chemotherapy: This involves using drugs to shrink cancer cells, making them easier to remove surgically. Chemotherapy is often used before surgery to reduce the tumor size and after surgery to eliminate any remaining cancer cells. It is commonly combined with radiation therapy and can also be paired with targeted drug therapy.
- Radiation Therapy: This treatment uses high-energy beams like X-rays to destroy cancer cells. While radiation alone is not typically effective for stomach cancer, it can be beneficial when used in conjunction with chemotherapy before or after surgery. It can also help alleviate symptoms.
- Targeted Drug Therapy: This approach focuses on the specific vulnerabilities of cancer cells, causing them to die. It’s often used alongside chemotherapy, especially for recurrent or advanced cancer.
- Immunotherapy: This treatment helps the immune system recognize and destroy cancer cells, particularly in cases of advanced or recurring cancer.
- Palliative Care: This specialized medical care focuses on improving the quality of life for those with cancer. A team of doctors, nurses, and other specialists work to relieve symptoms and provide additional support alongside your regular treatment.
Prevention of Stomach Cancer
While you cannot entirely prevent stomach cancer, there are ways to reduce your risk:
- Treat H. pylori Infection: If you test positive for H. pylori, treating the infection can lower your risk, as it is a significant contributor to stomach cancer.
- Manage Stomach Conditions Promptly: Addressing ulcers, gastritis, and other stomach conditions, especially those caused by H. pylori, can reduce your risk of cancer.
- Healthy Diet: Eating a balanced diet rich in fruits and vegetables while limiting salt and red meat can decrease your chances of developing stomach cancer. Foods high in vitamin C, beta-carotene, and carotenoids, such as citrus fruits, leafy greens, and carrots, are particularly beneficial.
- Avoid Tobacco: Smoking and the use of tobacco products increase your risk of stomach cancer and other cancers.
- Maintain a Healthy Weight: Consult with your healthcare provider to determine what a healthy weight means for you and strive to maintain it.
Is Stomach Cancer Curable ?
Stomach cancer can be cured if detected in its early stages. However, it is often diagnosed later, after symptoms have appeared. Discuss with your provider the factors that could influence your treatment outcomes.
What is the Prognosis for Stomach Cancer ?
The outlook for stomach cancer largely depends on the cancer’s stage at diagnosis. Early-stage stomach cancer has a much better prognosis compared to advanced-stage cancer. The 5-year survival rate can range from as high as 70% for localized cancer to as low as 6% for advanced cases. Your specific prognosis will depend on factors such as the type of cancer, its spread, your overall health, and how well your cancer responds to treatment. Consult your healthcare provider for a more personalized assessment.
When Should I See My Doctor ?
If you are at higher risk for stomach cancer, consider discussing the pros and cons of regular screenings with your provider. It’s also important to monitor your symptoms closely. Many symptoms of stomach cancer can also be signs of other conditions, so only your healthcare provider can make a definitive diagnosis. Seek medical advice if you experience symptoms like stomach pain or unexplained weight loss, along with:
- Difficulty eating
- Diarrhea
- Nausea
- Blood in your stool or black, tarry stools.
Also read: Ewing’s Sarcoma: The Silent Threat to Young Lives
