CONDITIONS
Stomach (Gastric) Cancer
What is stomach (gastric) cancer?
Stomach cancer, also known as gastric cancer. Gastric cancer usually originates in the inner lining of the stomach where cancer cells begin to form.
Stomach cancers tend to develop slowly over a long period. Before cancer forms, there are often pre-cancerous changes in the stomach lining that go unnoticed because they do not cause symptoms.
It is the fifth most common cancer among males and the seventh most common cancer in females in India. High consumption of salt-preserved foods and infection with Helicobacter pylori bacteria can significantly increase the risk of the disease.
Who gets stomach cancer?
Anyone can get stomach cancer, but certain factors may increase the risk of developing stomach cancer, including:
- Age: Stomach cancer is more common in older adults, with the risk increasing with age over 65.
- Gender: Males are nearly twice as likely as females to be diagnosed with stomach cancer.
- Family history: Individuals with a family history of stomach cancer are at higher risk.
- Dietary factors: Consumption of certain foods, such as smoked or salt-preserved foods, pickled vegetables, poorly preserved food, and processed meats, may increase the risk of stomach cancer.
- Helicobacter pylori infection: Infection with H. pylori bacteria is a major risk factor for stomach cancer.
- Tobacco use: Smoking increases the risk of stomach cancer.
- Alcohol consumption: Excessive alcohol consumption may also increase the risk.
- Environmental and occupational exposures: Individuals who work in the rubber or coal industry are prone to stomach cancer. Individuals exposed to very high levels of radiation are also at increased risk of stomach cancer.
- Obesity
What are the types of stomach cancer?
- Adenocarcinoma: This is the most common type of stomach cancer, accounting for most cases. Adenocarcinoma arises from the glandular cells lining the inner surface of the stomach.
- Gastroesophageal junction adenocarcinoma (GEJ): This is a cancer that forms in the area where the oesophagus meets the gastric cardia.
- Gastrointestinal stromal tumours (GISTs): GISTs are rare tumours that develop in the nerve cells that are found in the wall of the stomach and other digestive organs.
- Gastrointestinal neuroendocrine tumours: These tumours are cancers that begin in neuroendocrine cells (a type of cell like a nerve cell and a hormone-making cell) that line the gastrointestinal tract. Neuroendocrine cells make hormones that help control digestive juices and the muscles used in moving food through the stomach and intestines.
What are the symptoms of stomach cancer?
Stomach cancer is difficult to detect in its early stages as it often does not show any symptoms. Symptoms usually appear only after the cancer has spread to other parts of the body.
The symptoms of stomach cancer include:
- Loss of appetite
- Difficulty swallowing
- Fatigue or weakness
- Nausea and vomiting
- Unexplained weight loss
- Heartburn and indigestion
- Black stool or vomiting blood
- Feeling bloated or gassy after eating
- Stomach pain, usually above the belly button
- Feeling full even after eating a small meal or snack
If any of these symptoms are present, it is crucial to consult with a doctor, as these could be attributed to various conditions other than stomach cancer.
How is stomach cancer diagnosed?
The doctor may inquire about personal and family medical history to understand possible risk factors for stomach cancer, perform a physical exam, including feeling the abdomen for abnormalities, conduct blood tests to check for anaemia (low red blood cell count) as a potential sign of stomach bleeding and examine the stool for hidden (occult) blood, which could indicate stomach bleeding. Based on these findings, further tests may be recommended to diagnose stomach cancer.
The following tests and procedures are used to diagnose stomach cancer.
Upper endoscopy with biopsy: A thin, flexible tube with a camera (endoscope) is passed through the mouth and into the oesophagus, stomach, and duodenum. The doctor can visually inspect these organs for ulcers or any other abnormalities. They may also take tissue samples (biopsies) during the procedure to test for the presence of H. pylori bacteria or to check for signs of cancer.
Upper GI Series: Also known as a barium swallow or barium meal, this test involves swallowing a chalky liquid containing barium, which coats the oesophagus, stomach, and duodenum. X-rays are then taken, which can reveal ulcers, inflammation, or other abnormalities.
CT scan: A computed tomography (CT) scan of the abdomen may be performed to evaluate the size and location of the tumour, as well as to assess whether the cancer has spread to other organs or lymph nodes.
Laparoscopy: Laparoscopy is a diagnostic procedure used to look at the organs inside the abdomen to assess the spread of cancer when imaging techniques have not provided sufficient information. It involves the insertion of a small camera through tiny incisions in the abdomen, allowing the doctor to visualize the organs directly.
Biomarker testing: Biomarker testing is a method used to identify genes, proteins, and other substances (known as biomarkers or tumour markers) that can offer insights into cancer. Certain biomarkers can impact the effectiveness of specific cancer treatments. Biomarker testing can assist in selecting an appropriate cancer treatment. To detect these biomarkers, tissue samples containing stomach cancer cells are extracted during a biopsy or surgery. These samples are then analysed in a laboratory to determine the presence of these biomarkers in the stomach cancer cells. For stomach cancer, biomarker testing includes the following:
- HER2: Cancer cells may show elevated levels of the protein HER2.
- PD-L1: Cancer cells may have increased immune checkpoint protein PD-L1 levels.
- Microsatellite instability: It describes cancer cells that have a high number of mutations (changes) within microsatellites. Microsatellites are short, repeated sequences of DNA. Microsatellite instability-high cancer cells may have a defect in the ability to correct mistakes that occur when DNA is copied in the cell. Microsatellite instability is found most often in colorectal cancer, gastric cancer, and endometrial cancer, but it may also be found in many other types of cancer. Knowing whether cancer is microsatellite instability-high may help plan the best treatment.
- Mismatch repair deficiency: Cancer cells may have a defect in a mismatch repair gene, which may lead to cancer.
- Tumour mutational burden: High tumour mutational burden indicates the presence of numerous gene mutations in the cells.
- NTRK: The cancer cells may have changes in one of the NTRK genes.
Who treats stomach cancer?
Stomach cancer is often treated by a team of doctors with different specialties. Most likely, the team will include:
- A gastroenterologist: a doctor who specializes in treating diseases of the digestive system
- A surgical oncologist: a doctor who treats cancer with surgery
- A medical oncologist: a doctor who treats cancer with medicines such as chemotherapy and targeted therapy
- A radiation oncologist: a doctor who treats cancer with radiation therapy
What are treatment options for stomach cancer?
The main treatment options for gastric cancer are:
- Surgery: Depending on the extent of cancer spread, the doctor may recommend surgery to remove pre-cancerous cells, a tumour, or part or all of the stomach.
- Upper endoscopy is used in the early stages when the cancer is confined to the superficial layers of the stomach. During this procedure, known as endoscopic submucosal dissection or endoscopic mucosal resection, a gastroenterologist cuts out the tumour from the stomach wall and removes it through the mouth.
- Gastrectomy is necessary when the tumour has spread beyond the superficial layers of the stomach. Subtotal gastrectomy removes the cancer-affected portion of the stomach, while total gastrectomy removes the entire stomach. After total gastrectomy, the doctor will connect oesophagus to small intestine to ensure an individual can still eat.
- Chemotherapy: Chemotherapy shrinks cancer cells for easier removal before surgery and can kill remaining cells after surgery.
- Radiation therapy: Radiation uses energy beams to destroy cancer cells and may be used with chemo for stomach cancer treatment.
- Targeted drug therapy: Targeted therapy for stomach cancer involves using medicines that specifically target molecules or pathways involved in cancer growth and progression. These therapies are designed to interfere with specific proteins or processes that are overactive or abnormal in cancer cells while minimizing damage to healthy cells. Egs. include HER2-targeted therapy, immune checkpoint inhibitors, EGFR inhibitors. Targeted therapy for stomach cancer is often used in combination with chemotherapy or other treatments and is tailored to the individual characteristics of the tumour.
How can one reduce the risk of stomach cancer?
Reducing the risk of stomach cancer involves adopting healthy lifestyle habits and avoiding known risk factors. Here are some strategies to help reduce the risk of gastric cancer:
- Healthy diet: Consume a balanced diet rich in fruits, vegetables, whole grains, and lean proteins. Limit intake of processed meats, smoked or salt-preserved foods, and pickled vegetables, as these may increase the risk of gastric cancer.
- Avoid tobacco: Smoking is a significant risk factor for gastric cancer, as well as other types of cancer and health conditions.
- Healthy weight: Maintain a healthy weight through regular exercise and a balanced diet. Obesity is a risk factor for gastric cancer, as well as many other chronic diseases.
- pylori infection: Seek treatment if diagnosed with H. pylori infection.
In summary, stomach cancer, also known as gastric cancer, is a disease in which cancer cells form in the lining of the stomach. Stomach cancer often develops slowly over many years and may not cause symptoms in the early stages. However, as the cancer progresses, symptoms may include abdominal pain, bloating, nausea, loss of appetite, unexplained weight loss, and difficulty swallowing. Risk factors for stomach cancer include infection with H. pylori bacteria, a family history of the disease, smoking, obesity, and certain dietary factors. Diagnosis typically involves imaging tests such as endoscopy and biopsy to confirm the presence of cancer cells. Treatment options for stomach cancer may include surgery, chemotherapy, radiation therapy and targeted therapy depending on the spread and characteristics of the cancer. Early detection and prompt treatment are key to improving outcomes for individuals with stomach cancer.
References
- Sharma A, Radhakrishnan V. Gastric cancer in India. Indian J Med Paediatr Oncol. 2011 Jan;32(1):12-6.
- World Cancer Day 2024: Cancer Expert Lists 5 Facts About India’s 5 Most Common Cancers. Available from: https://www.onlymyhealth.com/facts-about-most-common-cancer-in-india-1706859845. Accessed on May 8th 2024
- National Cancer Institute. What is stomach cancer? Available from: https://www.cancer.gov/types/stomach#:~:text=Stomach%20(gastric)%20cancer%20is%20cancer,the%20mouth%20to%20the%20anus. Accessed on May 8th 2024
- Cleveland Clinic. Stomach cancer. Available from: https://my.clevelandclinic.org/health/diseases/15812-stomach-cancer. Accessed on May 8th 2024
- American Cancer Society. Available from: https://www.cancer.org/cancer/types/stomach-cancer/about/what-is-stomach-cancer.html. Accessed on May 8th 2024
