In its early stages, stomach cancer often goes unnoticed because signs such as bloating, indigestion and mild abdominal discomfort are commonly dismissed as routine digestive issues or simply “just ageing”.
While several tests are available to assess the stomach, each varies in its ability to detect early changes.
In this article, we outline the common investigations used to evaluate the stomach and explain why endoscopy is generally regarded as the most reliable method for confirming or ruling out stomach cancer.
What are the screening tests available for stomach cancer?
When a patient presents with persistent upper abdominal symptoms or has risk factors such as H. pylori infection or a family history of gastric cancer, doctors may recommend several investigations to determine the underlying cause.
Common tests include:
- Blood tests: to detect anaemia or tumour markers (though these are not specific to stomach cancer).
- Imaging scans (CT or MRI): to visualise the stomach and surrounding structures for masses or spread.
- Gastroscopy (Upper Endoscopy): Allows a direct view of the stomach lining and enables tissue sampling (biopsy) for accurate diagnosis.
| What It Does | Limitations |
|---|---|
| Blood tests: May detect tumour markers or anaemia |
Blood tests: Not specific or sensitive for stomach cancer |
| CT/MRI Scans: Show masses, thickening, or spread of cancer |
CT/MRI Scans: Cannot confirm if a mass is cancerous |
| Barium X-Ray: Outlines stomach shape and contour |
Barium X-Ray: Less commonly used today due to lower accuracy |
| Endoscopy: Directly visualises the stomach and allows biopsy |
Endoscopy: Minor discomfort, but safest and most accurate |
Note: While blood tests and imaging can suggest abnormalities, only an endoscopy can confirm the diagnosis with certainty.
Why endoscopy is generally viewed as the most definitive test for stomach cancer
An endoscopy (or gastroscopy) involves inserting a thin, flexible tube with a camera through the mouth to examine the stomach:
This allows the doctor to view the stomach lining in real time, identify any suspicious areas such as growths, ulcers or inflammation, and take biopsy samples for laboratory analysis.
Unlike tests that provide only indirect clues, such as digestive tumour marker assessments, endoscopy offers direct visualisation and the opportunity for tissue sampling. A definitive diagnosis of stomach cancer requires a biopsy, which is obtained during an endoscopy
Why did my doctor order other tests then?
Patients often wonder — if endoscopy is the most accurate way to diagnose stomach cancer, why are blood tests, imaging scans or other investigations still necessary?
It’s a reasonable question.
In short, each test has its own important role. These investigations help assess your overall health, pick up potential complications and provide supplementary information that supports your doctor in planning the most appropriate care.
When should you consider an endoscopy?
You may be advised to undergo an endoscopy if you experience:
- Persistent or unexplained upper abdominal pain
- Persistent bloating, indigestion, or early fullness
- Unexplained weight loss or loss of appetite
- Vomiting or passing black stools
- Family history of stomach cancer
If you have risk factors such as H. pylori infection, long-term gastritis, or are over 50 years old, regular endoscopic screening may also be recommended for early detection.
Most importantly, if you simply want peace of mind, you can choose to undergo an endoscopy or gastroscopy at any time – especially as stomach cancer rates are rising among younger individuals.
With available subsidies and private insurance coverage, endoscopy has become much more accessible today.
Summary
While blood tests and imaging provide useful information, endoscopy remains the most reliable way to assess the stomach when there is concern about cancer.
It allows doctors to view the stomach lining directly and obtain tissue samples, which are essential for confirming a diagnosis.
If you’ve been experiencing ongoing digestive symptoms or have risk factors for stomach cancer, consider discussing your concerns with a gastroenterologist to determine whether an endoscopy may be appropriate for you.
Considering your next steps
If certain symptoms have been persisting or something simply does not feel right, speaking with a gastroenterologist can help clarify what tests may be appropriate.
You can explore these concerns further with our gastroenterology clinic in Singapore, where our doctor will guide you on the most suitable next steps.
While blood tests and imaging can suggest abnormalities, only an endoscopy can confirm the diagnosis with certainty.Tumour marker tests are not 100% accurate.
References:
- Bredenoord, A. J., & de Wit, N. J. (2021). Wel of geen gastroscopie? [Who should undergo upper endoscopy?]. Nederlands tijdschrift voor geneeskunde, 165, D6179.
- https://cancerblog.mayoclinic.org/2025/02/11/as-stomach-cancer-rates-rise-in-younger-people-knowing-symptoms-and-family-history-is-key/
