Stomach Cancer: Symptoms, Causes, Stages, Types & Treatment 

Introduction

Persistent indigestion, stomach discomfort, or unintentional weight loss can be a cause for concern, especially if the symptoms persist or recur. In many cases, these symptoms may be caused by common digestive problems¹. However, when such symptoms continue or become worse, they should not be ignored, as they can sometimes be linked to stomach cancer. In this blog, we will discuss stomach cancer, its stages, symptoms, causes, treatment options, and when to seek medical attention. 

What Is Stomach Cancer?

The stomach is a muscular organ in the upper abdomen that helps break food down during digestion. Stomach cancer, also known as gastric cancer, is a type of cancer that begins when cells in the stomach start growing abnormally and uncontrollably. The most common type of stomach cancer is adenocarcinoma, which develops from the mucus-forming cells in the innermost lining of the stomach^2,3. Over time, abnormal cells from this lining can grow deeper into the stomach wall and may eventually spread to other organs². 

In the early stages, stomach cancer may have mild to no symptoms, making it difficult to notice¹. This is why ongoing or unusual digestive symptoms should be evaluated by a doctor rather than being treated as simple indigestion that occurs repeatedly⁴. 

Early vs Advanced Symptoms of Stomach Cancer

Stomach cancer symptoms may change as the disease progresses. The table below compares symptoms that may occur in the early and advanced stages of stomach cancer. 

Stomach Cancer Causes

Stomach cancer does not usually have a single cause. It develops when changes in the cells of the stomach cause them to grow and multiply abnormally. Factors that may increase the chance of these changes include: 

• Helicobacter Pylori (H. pylori) Infection: This bacterium can cause long-term inflammation and damage to the stomach lining, which may increase the chance of stomach cancer. 
• Chronic Gastritis or Gastric Ulcers: Severe ongoing inflammation can gradually damage stomach cells and may contribute to abnormal cell changes. 
• Intestinal Metaplasia: Certain changes in the stomach lining can cause its usual cells to change into cells that are more similar to those found in the intestine. Please note that intestinal metaplasia is not cancer, but it is considered a precancerous change because, in some people, it may increase the risk of developing stomach cancer over time. 
• Epstein-Barr Virus (EBV) Infection: In some people, infection with EBV may cause changes in stomach cells that are linked to the development of certain types of stomach cancer. 
• Inherited Conditions: Rare genetic conditions such as Lynch syndrome and juvenile polyp syndrome can affect how cells behave and may contribute to a higher chance of developing stomach cancer⁵.

Who Is at Risk of Developing Stomach Cancer?

Certain factors can make a person more likely to develop stomach cancer. These include: 

• Age: Older people are at a higher risk of getting stomach cancer. The greatest number of stomach cancer cases are reported between the ages of 60 and 80^5,6. 
• Gender: Stomach cancer occurs more often in men than in women. 
• Family History: Having a parent, brother, sister, or child who has had stomach cancer can increase the risk. 
• Tobacco: People who smoke and chew tobacco have double the risk of stomach cancer compared with non-smokers⁶.
• Diet: Frequently eating foods that are heavily salted, smoked, or poorly preserved may increase the risk.  
• Obesity: Obesity may also increase the risk.  
• Workplace Exposures: People working in industries such as rubber, metal, radiation, or coal may have an increased risk because of occupational exposures^5,6. 
• Blood Group: People belonging to specific blood groups, such as type A, are at higher risk⁵.
• Geographical and Population Differences: Stomach cancer is more common in certain populations and regions, particularly in parts of East Asia, Eastern Europe, and Central and South America⁶.

Note: Having any of these risk factors does not mean that a person will develop stomach cancer. These factors only indicate that the likelihood of stomach cancer may be higher. If you have concerns about your risk or experience persistent digestive symptoms, speak with your doctor for appropriate advice and evaluation. 

Types of Stomach Cancer

There are different types of stomach cancer based on the type of cells they originate in. 

• Adenocarcinoma: This is the most common type of stomach cancer. It starts in the gland-forming cells that produce mucus and other digestive fluids in the stomach lining. Stomach adenocarcinoma can be further divided into two main forms: 
  • Intestinal type: The cancer cells look more similar to normal stomach cells and often grow in gland-like or tube-like patterns. This type may have a slightly better prognosis. 
  • Diffuse type: The cancer cells look more unusual and do not form clear patterns. This type is less common, more aggressive, and may be difficult to treat. 
• Gastrointestinal stromal tumour (GIST): GIST develops in certain cells in the stomach wall called interstitial cells of Cajal. GISTs can occur anywhere along the digestive system but mostly begin in the stomach. 
• Neuroendocrine Tumours (NETs): These cancers develop from special cells in the stomach that have features of both nerve cells and hormone-producing cells. Many NETs grow slowly and may remain limited to the stomach, while some can grow faster and spread to other parts of the body. 
• Lymphoma: This type of cancer begins in the lymphocytes, which are white blood cells that help the body fight infections. Although lymphoma usually starts in other parts of the body, it can sometimes develop in the stomach. Note that a type called gastric MALT lymphoma is strongly linked to H. pylori infection⁷. 

Note: There are certain other types of cancers, such as squamous cell carcinoma, small cell carcinoma, and leiomyosarcoma, that can develop in the stomach. However, these forms are uncommon. 

Stomach Cancer Stages

Stomach cancer can be divided into different stages: 

1. Stage 0

During this stage, abnormal or cancerous cells are limited to the innermost layer of the stomach lining (mucosa) and have not invaded deeper tissues but can spread to nearby parts. This is also called carcinoma in situ. 

2. Stage I

Stage I stomach cancer is divided into Stage IA and Stage IB, depending on the spread of the cancer and whether nearby lymph nodes are affected. 

• Stage IA: The cancer is found in the mucosa and may have grown into the layer just beneath it (submucosa). 
• Stage IB: The cancer may have affected the mucosa and submucosa and may have reached 1 or 2 nearby lymph nodes or it may have affected the mucosa and grown into the muscle layer. 

3. Stage II

Stage II stomach cancer is divided into Stage IIA and Stage IIB based on how deeply the cancer has grown into the stomach wall and how many nearby lymph nodes are affected. 

• Stage IIA: The cancer may have reached the submucosa and spread to 3-6 nearby lymph nodes or it may have grown into the muscle layer and affected 1-2 nearby lymph nodes or it may have spread to the tissue between the muscle layer and the outer covering of the stomach (subserosa). 
• Stage IIB: The cancer may have affected the submucosa and spread to 7-15 nearby lymph nodes or it may have grown into the muscle layer and affected 3-6 lymph nodes. It may even have spread to the subserosa along with 1-2 nearby lymph nodes or it may have reached the stomach’s outermost covering (serosa). 

4. Stage III

Stage III stomach cancer is divided into Stages IIIA, IIIB and IIIC. At this stage, the cancer has grown deeper into the stomach wall and may have spread to several nearby lymph nodes or surrounding organs. 

• Stage IIIA: The cancer may have grown into the muscle layer of the stomach and spread to 7-15 nearby lymph nodes or spread to the subserosa and 3-6 nearby lymph nodes or spread to the serosa and 1-6 nearby lymph nodes. It may have reached nearby organs, such as the liver, pancreas, spleen, colon, kidney, small intestine or back of the abdomen. 
• Stage IIIB: The cancer may have spread to the submucosa and affected 16 or more nearby lymph nodes. It may also have spread to the subserosa and affected 7-15 nearby lymph nodes or reached nearby organs, such as the adrenal gland, kidney, or small intestine or spread to 1-6 lymph nodes. 
• Stage IIIC: The cancer has grown into the subserosa or serosa and spread to 16 or more nearby lymph nodes or to organs such as the spleen, liver, colon, or diaphragm and affected 7 or more nearby lymph nodes. 

5. Stage IV

The cancer at this stage has spread from the stomach to other distant parts of the body, such as the liver, lungs, distant lymph nodes or the lining of the abdomen. This stage is also known as metastatic stomach cancer. The cancer that has spread to other organs is the same type as the original tumour. For example, stomach cancer that spreads to the lungs will still have stomach cancer cells and it will be called metastatic stomach cancer⁸. 

How Is Stomach Cancer Diagnosed?

If stomach cancer is suspected, doctors may use a combination of tests to confirm the diagnosis, determine the extent of the disease and choose the most appropriate treatment. The common diagnostic tests include: 

• Clinical Evaluation: The doctor will ask about symptoms such as ongoing indigestion, stomach pain, reduced appetite or unexplained weight loss. They will review your personal or family history of cancer or any disease and perform a physical examination. 
• Upper endoscopy: A thin, flexible tube with a small camera is passed through the mouth into the stomach. This allows the doctor to examine the stomach lining for unusual areas. 
• Biopsy: If a suspicious area is found during endoscopy, small pieces of tissue may be removed and examined under a microscope to check for cancer cells (the endoscopy device usually has a tool to take the sample for biopsy). A biopsy may help to identify infections such as those caused by H. pylori. 
• Imaging tests: Imaging tests such as positron emission tomography-computed tomography (PET-CT), magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS) may be used to examine the stomach and surrounding tissues. PET scan uses a small amount of radioactive glucose to highlight areas of increased activity, while CT provides detailed images to help identify cancer and possible spread. MRI uses magnets and radio waves to create detailed images, and EUS uses ultrasound waves, passed via an endoscope, to show the stomach wall and help doctors assess how the cancer has grown. 
• Laparoscopy: In some cases, doctors use a small camera inserted through a tiny cut in the abdomen to examine the stomach and nearby areas. This can help identify cancer that may not be clearly visible on imaging scans. They usually collect a sample to check for cancer. 
• Biomarker testing: Tests may be performed on the tumour tissue to look for specific markers or genetic changes. They may look for markers such as HER2, PD-L1, and NTRK, among others⁹. 
• Other Laboratory Tests: The doctor may recommend blood tests, such as a complete blood count (CBC), to check for signs of anaemia caused by stomach bleeding. Liver and kidney function tests may also be performed to assess the baseline wellbeing. A stool test may be done to detect hidden blood in the stool^9,10.

Stomach Cancer Treatment

Stomach cancer treatment depends on factors such as the cancer stage, its location, the individual’s overall health, and whether the cancer has spread to other parts of the body. Doctors may use one treatment or combine several approaches as needed. 

• Surgery: Surgery may be recommended to remove the tumour along with some surrounding healthy tissue. In some cases, part of the stomach is removed, while advanced tumours may require removal of the entire stomach, followed by reconstruction of the lumen to maintain continuity of the digestive tract. The decision of surgery depends on the severity and type of cancer. 
• Chemotherapy: This approach uses medicines that destroy cancer cells or slow their growth. It may be given as an injection or as oral medicine. , Depending on the oncologist’s decision, it may be used before or after surgery at any stage of stomach cancer to help control the disease. Examples of routinely used drugs: Capecitabine, cisplatin, and docetaxel. 
• Radiation Therapy: This treatment uses localised high-energy radiation to damage cancer cells or restrict them from growing. It may be used along with chemotherapy before or after surgery for some stage II and stage III cancers. In stage IV disease, it may also be used for palliative symptom relief such as pain, bleeding or blockage. 
• Targeted Therapy: This uses medicines or drugs to act on specific types of cancer cells to restrict their growth. For example, some patients whose tumours have certain markers, such as HER2, may benefit from HER2-targeted treatment. It is mainly used for advanced or stage IV stomach cancer. Examples: Trastuzumab and trastuzumab deruxtecan, in cases of HER2-positive tumours. 
• Immunotherapy: This treatment uses drugs that help the immune system recognise and attack cancer cells. They use more than one way to destroy cancer cells. It is mainly considered for advanced or stage IV stomach cancer and may be combined with chemotherapy. Examples: Nivolumab and pembrolizumab^11,12. 

Can Stomach Cancer Be Prevented?

Not every case of stomach cancer can be prevented. However, certain measures may help reduce its risk: 

• Treat H. pylori infection, follow your doctor’s treatment plan to clear the infection and protect the stomach lining. 
• Include plenty of fresh fruits, vegetables, whole grains and other nutritious foods in your daily meals. 
• Avoid smoking or using tobacco products, as tobacco use can increase the risk of stomach cancer. 
• Avoid alcohol consumption. 
• Stay physically active by performing regular exercise, such as walking or cycling, which can support overall health and help maintain a healthy weight¹³. 
• Limit foods that contain high amounts of salt or are frequently smoked, pickled or preserved⁶.
• If close family members have had stomach cancer or you have other risk factors, discuss your risk with a doctor and follow their advice regarding cancer screening. 

Note: These steps may help lower the risk of stomach cancer; however, they may not be able to prevent every case. Your risk can also be influenced by factors such as family history and other health conditions. Speak with a doctor for personalised advice if you have concerns about your risk factors. 

When to Consult a Doctor?

See a doctor if digestive problems persist, keep coming back or worsen over time. Seek medical advice for symptoms such as unexplained weight loss, ongoing indigestion, repeated vomiting, difficulty swallowing, loss of appetite, feeling full quickly, blood in vomit or black (or red) stools, unusual tiredness, swelling or persistent abdominal pain. These symptoms can occur with many common digestive problems and do not necessarily mean stomach cancer. However, it is important to consult your doctor for persistent symptoms as this may help find the cause early and ensure appropriate treatment¹.

Also Read: Is Bowel Leakage a Sign of Cancer?

Conclusion

Being aware of changes in digestion and other unusual stomach symptoms can help encourage early medical evaluation. Knowing your personal risk factors and following healthy habits may help lower the chances of developing stomach cancer. If symptoms do not settle or become more severe, seeing a doctor promptly can help identify the cause and guide you to the right treatment. 

Frequently Asked Questions (FAQs)

References

1. Stomach cancer symptoms. NCI. 2024. Available from: https://www.cancer.gov/types/stomach/symptoms 

2. Stomach cancer. Cancer Research UK. Available from: https://www.cancerresearchuk.org/about-cancer/stomach-cancer 

3. What is stomach cancer? NCI. Available from: https://www.cancer.gov/types/stomach 

4. Menon G, El-Nakeep S, Babiker HM. Gastric cancer. In: StatPearls. StatPearls Publishing; 2024. Available from: http://www.ncbi.nlm.nih.gov/books/NBK459142/ 

5. Causes of stomach cancer – NCI. 2025.Available from: https://www.cancer.gov/types/stomach/causes-risk-factors 

6. Stomach cancer risk factors. American Cancer Society. 2026. Available from: https://www.cancer.org/cancer/types/stomach-cancer/causes-risks-prevention/risk-factors.html 

7. Stomach cancer. American Cancer Society. 2026. Available from: https://www.cancer.org/cancer/types/stomach-cancer.html 

8. Stages of stomach cancer. NCI. 2023. Available from: https://www.cancer.gov/types/stomach/stages#stage-0-carcinoma-in-situ-of-the-stomach 

9. Stomach cancer diagnosis. NCI. 2023. Available from: https://www.cancer.gov/types/stomach/diagnosis 

10. Tests for stomach cancer. Cancer Research UK. 2025. Available from: https://www.cancerresearchuk.org/about-cancer/stomach-cancer/getting-diagnosed/tests-stomach-cancer 

11. Stomach cancer treatment. NCI. 2025. Available from: https://www.cancer.gov/types/stomach/treatment 

12. Stomach cancer treatment by stage. NCI. 2025. Available from: https://www.cancer.gov/types/stomach/treatment/by-stage 

13. Stomach cancer causes, risk factors, and prevention. American Cancer Society. 2026.Available from: https://www.cancer.org/cancer/types/stomach-cancer/causes-risks-prevention.html 

14. Stomach cancer survival rates and statistics. NCI. 2023. Available from: https://www.cancer.gov/types/stomach/survival

15. Murakami K, Matsubara H. Chronology of gastrointestinal cancer. Surg Today. 2017;48(4):365-370. doi:10.1007/s00595-017-1574-y https://pubmed.ncbi.nlm.nih.gov/28795270/

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