Stomach Cancer: Symptoms, Causes, Types & PET-CT as a Diagnostic Tool

Sometimes stomach cancer is referred to as gastric cancer, in which the abnormal cells begin to grow out of control in the lining of the stomach. It is typically slow to develop and may not be readily apparent until late in the season. As the disease advances the cancer can lead to stomach upset, abdominal pain, nausea, loss of appetite, a decreased appetite and weight loss.

The diagnosis of early stomach cancer makes a major part in the treatment management of stomach cancer. Doctors may perform blood tests, an endoscopy, a biopsy, a CT scan, or a PET-CT to confirm the diagnosis of the disease and to establish the overall extent of the disease.

Molecular Diagnostics and Therapy offers sophisticated diagnostic imaging capabilities, which aid physicians in assessing cancer and deciding on the appropriate care. Let's see what the symptoms, cause, type, and importance of PET CT in stomach cancer diagnosis are.

What Is Stomach Cancer?

The abnormal change of the cells that line the stomach may contribute to Stomach Cancer. The abnormal cells will start to multiply at an uncontrolled rate and start to form a lump, or tumour. This may result in deeper tissues in your stomach being damaged. Later on, this can lead to the spread of the cancer to other parts of the body or to the close tissues and cells that drain as well. The traits of cancer in the upper, middle, or lower part of the stomach are different, and so are the treatments of the cancer – symptoms and treatment depend on the site of cancer in the stomach, the type of cancer, and the stage.

Common Symptoms of Stomach Cancer

Early signs and symptoms may resemble typical tummy ailments. The most common symptoms of stomach cancer are:

• Repeated indigestion: Upper abdominal pain or burning sensation.
• Regular vomiting/nausea: Increased vomiting/nausea with no apparent reason.
• Loss of appetite: Food does not taste as nice as it used to and feeling full quicker when eating.
• Unexpected weight loss: Losing weight quickly with no changes to diet, exercise, or lifestyle.
• Blood in vomit/stools: Vomiting or dark tar-like stools.
• Fatigue: Constant tiredness sometimes due to anaemia caused by blood loss.

While these symptoms may not indicate you have cancer, you should see your health care provider if the symptoms are chronic or irritating to your GI tract.

What Causes Stomach Cancer?

In some cases, the cause of stomach cancer can't be determined. However, loads of risk factors exist that will probably improve the odds of acquiring the condition.

• Smoking: Smokers make up twice as many people as non-smokers who suffer from stomach cancer.
• Eating habits: People who eat a large amount of salt, smoke, or pickled foods are at a higher risk.
• Chronic stomach ailments: Persistent stomach irritation and a few changes in the stomach lining might raise the danger of developing stomach cancer.
• Obesity: Extra body weight increases the risk of some cancers, such as some cancers near the junction of the stomach and oesophagus.

If a person has a risk factor or risk factors, this does not mean that he or she will definitely develop stomach cancer.

Different Types of Stomach Cancer

The classification of stomach cancer is based on the type of cells and tissues in the stomach where the cancer originates. 

1. Gastric Adenocarcinoma

This is the most common type of stomach cancer. It begins in the lining of the stomach in the glandular cells. May occur in various forms including intestinal or diffuse.

2. Gastrointestinal Stromal Tumour (GIST)

It's a tumour that develops from special cells in the gastrointestinal wall. It may begin in the stomach and may behave differently than other cancers.

3. Gastric Lymphoma

Gastric lymphoma is a type of lymphoma that develops in the stomach's lymphatic tissue. H. pylori infection is associated with certain gastric lymphomas, particularly gastric MALT lymphoma.

4. Gastric Neuroendocrine Tumours

These are tumours that occur in the stomach cells that make hormones. Depending on other factors of the tumour and its grade, the behaviour of the tumour can change.

How Is Stomach Cancer Diagnosed?

There are many tests that can be carried out to help diagnose stomach cancer and determine how far it has spread. Doctors might order the following tests:

• Upper Gastrointestinal Endoscopy: A flexible thin tube (endoscope) is used to examine the inside of the stomach.
• Biopsy: A procedure to take a small piece of tissue for microscopic examination to confirm the presence of cancer.
• Computerised Tomography (CT) Scan: A special type of X-ray which can be used to look at the stomach and other organs to see if cancer has spread.
• Endoscopic Ultrasound: This can be used to find out the extent to which the tumour has penetrated through the walls of the stomach and into any surrounding organs.

Tests used will depend on the person's health and the type of cancer that is suspected.

Role of PET-CT in Stomach Cancer Diagnosis

PET-CT is a combination of computerised tomography (CT) and positron emission tomography (PET). Uses a radioactive tracer – typically Fluorodeoxyglucose or FDG – to look at how glucose moves in body tissue. Using PET imagers can help to highlight areas that have increased glucose uptake, and CT can describe the anatomical location of the areas that have increased glucose uptake. PET-CT may help doctors:

• Evaluate for spread: Evaluate suspicious lymph nodes or distant areas for cancer spread.
• Assess the extent of disease: Supplement cancer staging with additional information.
• Monitor treatment response: Assist with treatment response monitoring.

However, not all stomach cancers are created equal, meaning it's possible for the stomach to accept high levels of FDG without it being stomach cancer. For some types of cancer, such as some diffuse or mucinous types, PET is not as sensitive. Therefore, PET-CT should not be performed in all patients, and should not replace endoscopy, biopsy, or other imaging tests.

Conclusion

In the early stages, there may not be any symptoms, but if you are experiencing symptoms such as heartburn, abdominal pain, unexplained weight loss, and problems with eating, then you should not ignore them. Getting an early diagnosis will help your doctor understand the disease and treat you. Some patients will benefit from having a PET-CT scan to give more information about how active the cancer is and/or how far it has spread. Molecular Diagnostics and Therapy provides a new type of diagnostic imaging to help doctors understand and plan cancer treatments.