How Is Stomach Cancer Diagnosed?

Stomach cancer is rare compared to other types of cancer, but it still affects more than 20,000 Americans every year. The risk of dying from stomach cancer before the age of 75 is roughly about 1.36% for men and 0.57% for women.¹ Additionally, the survival rate is about 71%. The bottom line is: stomach cancer isn't a death sentence.

Stomach cancer is easier to manage and treat when diagnosed early. Unfortunately, it is difficult to diagnose, and most people don't know that they are suffering from the condition until they have significant spread and the disease is quite advanced. Here is a brief overview of stomach cancer and a comprehensive guide on how it’s diagnosed.

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What is stomach cancer?

Stomach cancer is also called gastric cancer. It occurs when cells in the stomach start growing out of control. It can originate in any part of the stomach and spread throughout the entire gastric system and other surrounding organs.

It can cause a wide range of symptoms, including:

  • Nausea 

  • Vomiting 

  • Poor appetite 

  • Weight loss 

  • Indigestion 

  • Heartburn 

  • Abdominal pain

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Stomach cancer is categorized by several factors, such as its point of origin and the extent to which it has spread.

Four of the most common types of gastric cancer include:


Adenocarcinomas account for about 90% - 95% of all stomach cancers.² They originate in the gland cells in the stomach's inner-most lining (mucosa). These cancers are categorized into two types:

  • diffuse adenocarcinoma, which spreads quickly and is difficult to treat 

  • intestinal adenocarcinoma, which is easier to treat

GISTs (Gastrointestinal Stromal Tumors) 

GISTs originate in the stomach's interstitial wall. However, it is worth noting that they can originate anywhere in the digestive system. The tumors can also grow to other parts and organs beyond the stomach.

NETs (Neuroendocrine Tumors) 

Neuroendocrine tumors start in special stomach cells that function both as hormone production and nerve cells. NETs can spread quickly or slowly based on various factors, but they don't spread to other organs.


Lymphomas can originate in different organs around the body, including the stomach. However, stomach lymphoma is rare and accounts for only 2% of all lymphomas.

How is stomach cancer diagnosed?

There is a high likelihood of recovering from stomach cancer if diagnosed and treated early. However, one of the most challenging hurdles with this cancer is how difficult it is to diagnose. This is partly due to its slow spread; therefore, most symptoms are either very mild or don't show until it becomes quite advanced.

Fortunately, diagnosing stomach cancer is becoming easier and more accurate, thanks to advances in medicine. Common stomach cancer diagnosis tests include:

Initial Testing

A stomach cancer diagnosis begins with a quick overview of your overall health. It involves reviewing your personal and family medical history to determine the likelihood of developing stomach cancer. Risk factors such as smoking are also taken into consideration.

Your doctor will also inquire about common stomach cancer symptoms such as abdominal pain and bloating. They may also perform a quick physical exam to look for any abnormalities. Finally, they will recommend advanced tests if there is a credible reason for concern.

Upper Endoscopy

An upper endoscopy is the most common test used to identify stomach cancer. It involves inserting an endoscope through the mouth and down the throat and esophagus into the stomach. An endoscope is a thin and flexible tube fitted with a light and camera.

The endoscope enables the doctor to view and examine the stomach and other organs for abnormalities such as inflammation, ulcers, and tumors. It also allows the doctor to obtain biopsies of abnormal tissue for analysis via follow-up tests.

Sedation is necessary before undergoing an upper endoscopy test. However, it is worth noting that this test cannot detect all types of stomach cancer, making it essential to undergo follow-up tests.

Endoscopic Ultrasound (EUS)

Endoscopic ultrasound uses sound waves to examine the stomach and other organs for signs of cancer. The sound waves can penetrate through the stomach's different layers, making it possible to measure its spread and develop a more concise treatment plan. The waves can also reach organs such as the liver, bile duct, pancreas, and gallbladder.


A biopsy is a follow-up test that comes after an upper endoscopy finds inconclusive evidence of stomach cancer. It involves taking a small sample cell of the affected tissue and testing it for the presence of cancerous cells. It is the only way to be sure whether or not cancer is present.

Lab Tests

Your gastroenterologist may also recommend a series of lab tests to help diagnose stomach cancer. These tests may include the following:

Complete Blood Count 

A stomach cancer blood test involves a complete blood count. It can determine the number and different types of cells in your blood. Anemia, or a low hemoglobin count, is often the first abnormal result that may suggest some bleeding pathologies, such as a tumor or ulcer, in the digestive tract.

Advanced Genomic Testing 

Advanced genomic testing is used to examine a cancerous tumor's DNA and mutations. The results help doctors determine the cause and develop a more informed treatment plan.

Liver Function Testing

Stomach cancer often spreads to the liver, compromising its efficiency. A liver function test is used to assess your liver's overall functionality and performance.

Nutrition Panel Review

Nutrition is integral to your overall health, and some nutrients can help your body cope better with stomach cancer. A nutrition panel review can assess your nutritional intake and help you tailor a healthy diet.

Imaging Tests

People often wonder if a CT scan can be used to detect stomach cancer. Fortunately, non-invasive tests such as CT scans can not only diagnose but also stage stomach cancer. To this end, your doctor may recommend the following imaging tests:

  • Magnetic Resonance Imaging (MRI) 

  • Positron Emission Tomography (PET) Scan 

  • Upper Gastrointestinal Series 

  • Ultrasound 

Which doctors & specialists to see

Stomach cancer is a complex condition that can originate at different points and affect multiple organs. Consequently, diagnosing and treating this condition requires input from specialists in various fields, including:

  • A gastroenterologist who specializes in the gastrointestinal tract (which includes the stomach and small intestines).  

  • A medical oncologist specializing in medicines that treat cancer. 

  • A surgical oncologist specializing in surgeries that treat cancer. 

  • A radiation oncologist specializing in radiation therapy using high-energy x-rays. 

  • A radiologist specializing in administering and interpreting imaging tests. 

  • A pathologist specializing in administering and interpreting lab tests.

Other specialists whose input you may require are a dietitian, counselor, pharmacist, oncology nurse, and social worker, depending on your needs. The team should collaborate and coordinate closely to optimize care and maximize your likelihood of recovering. 

The lowdown

Stomach cancer is difficult to diagnose, but an early diagnosis can save lives. Regular testing is vital, especially if you are at an increased risk of developing stomach cancer due to pre-existing conditions or family history. It is also important to be aware of the common causes of stomach cancer to limit your chances of developing this condition later in life.

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