Can a Gastric Emptying Scan Show Cancer?

When it comes to diagnosing various gastrointestinal disorders, a gastric emptying scan is a common imaging test doctors use to evaluate how quickly food leaves the stomach. But can this scan also detect cancer? Understanding the purpose, capabilities, and limitations of a gastric emptying scan is important to determine its role in cancer diagnosis. In this article, we’ll explore how a gastric emptying scan works, whether it can show cancer, and what other imaging techniques may be more suitable for detecting cancerous growths.

What is a Gastric Emptying Scan?

A gastric emptying scan, also known as a gastric emptying study or test, is a specialized imaging test used to measure the speed at which food leaves the stomach and enters the small intestine. This test is often recommended for patients experiencing symptoms like nausea, vomiting, bloating, or unexplained weight loss. These symptoms could be related to various conditions such as gastroparesis, a disorder where the stomach takes too long to empty its contents.

During the scan, the patient consumes a small meal containing a radioactive material (tracer), usually mixed with food like scrambled eggs or oatmeal. The tracer emits gamma rays, which are detected by a gamma camera. The camera takes images at regular intervals to monitor the movement of the tracer through the stomach, helping doctors evaluate the stomach’s emptying rate.

Can a Gastric Emptying Scan Detect Cancer?

A gastric emptying scan is primarily designed to assess the stomach’s function, specifically how quickly it empties its contents. It is not specifically designed to detect cancer. The test can show abnormalities in the movement of food through the stomach, but it does not provide detailed images of the stomach’s structure or its surrounding tissues. Therefore, a gastric emptying scan is not typically used to diagnose cancer.

However, there are instances where a gastric emptying scan may indirectly suggest the presence of a tumor or cancerous growth. For example, if the scan shows a severe delay in gastric emptying, this could be due to a mass or obstruction in the stomach, such as a tumor. In such cases, further imaging tests, like a CT scan or endoscopy, would be required to confirm the presence of cancer.

Limitations of Gastric Emptying Scans in Cancer Detection

While gastric emptying scans are valuable for diagnosing motility disorders, they have limitations in detecting cancer. The main reasons why a gastric emptying scan may not effectively show cancer include:

1. Lack of Structural Detail: Gastric emptying scans focus on function, not structure. They do not provide high-resolution images of the stomach or surrounding tissues, making it challenging to detect abnormalities like tumors.
2. No Direct Visualization of Cancer: The scan only measures how quickly food leaves the stomach. It does not directly visualize or identify cancer cells or tumors.
3. False Positives and Negatives: In some cases, slow gastric emptying might not be caused by cancer but by other conditions like diabetes or nerve damage. Conversely, normal results do not rule out the presence of cancer elsewhere in the stomach or digestive tract.

Other Imaging Techniques for Detecting Cancer

To diagnose or rule out cancer, doctors may use endoscopy and a range of imaging techniques that provide a more detailed view of the stomach and surrounding tissues. These include:

1. CT Scan (Computed Tomography Scan)

A CT scan is a more advanced imaging technique that combines X-rays taken from different angles to create detailed cross-sectional images of the body’s internal structures. It can detect tumors, including those in the stomach. CT scans can show the size, shape, and location of a tumor and whether it has spread to other parts of the body.

2. MRI (Magnetic Resonance Imaging)

MRI uses powerful magnets and radio waves to create detailed images of soft tissues, such as the stomach lining. This imaging method can provide clearer images of soft tissue structures compared to a CT scan. It is particularly useful for identifying smaller tumors or for patients who cannot undergo a CT scan due to allergies to contrast material.

3. Endoscopic Ultrasound (EUS)

Endoscopic ultrasound is a combination of endoscopy and ultrasound technology. A thin, flexible tube with an ultrasound probe at its tip is inserted through the mouth and into the stomach. The ultrasound probe uses sound waves to create detailed images of the stomach walls and nearby organs. EUS is effective in detecting tumors within the stomach wall or in nearby lymph nodes, making it a tool in diagnosing stomach cancer.

4. PET Scan (Positron Emission Tomography Scan)

A PET scan involves injecting a radioactive sugar substance into the bloodstream. Cancer cells absorb this substance more quickly than normal cells, making them easier to detect. The PET scan camera detects areas where the radioactive substance has accumulated, helping to identify cancerous growths and determine whether cancer has spread.

When Should You Consider Other Imaging Tests?

If a patient exhibits symptoms that may indicate stomach cancer—such as unexplained weight loss, persistent abdominal pain, or vomiting with blood—doctors may consider imaging techniques beyond a gastric emptying scan. Endoscopy is often used for diagnosis.  For a more comprehensive evaluation, they may recommend a CT scan, MRI, EUS, or PET scan. These tests can provide more detailed information about the stomach’s structure, detect small tumors, and assess whether cancer has spread to other areas.

Conclusion

While a gastric emptying scan is a valuable tool for assessing how quickly the stomach empties its contents, it is not designed to diagnose cancer. The primary purpose of this scan is to evaluate stomach motility disorders, and it lacks the ability to provide detailed images needed to identify cancerous growths.

For detecting stomach cancer, endoscopy and other imaging techniques like CT scans, MRIs, endoscopic ultrasounds, and PET scans are more suitable. If you are concerned about the possibility of stomach cancer, it is essential to speak with your healthcare provider, who can recommend the appropriate specialist referrals and tests based on your symptoms and medical history.