Stomach Cancer

What is Stomach Cancer?

Stomach cancer, also known as gastric cancer, is a type of cancer that develops in the lining of the stomach. It is a serious and potentially fatal disease that requires early detection and treatment. Stomach cancer typically starts in the mucus-producing cells that line the stomach, and over time, it can spread to the deeper layers of the stomach. 

In Australia, stomach cancer is the fifth most commonly diagnosed cancer and the fourth leading cause of cancer death in the world.

How Does Stomach Cancer Impact Your Anatomy and Health?

Some of the most common ways that stomach cancer can impact your anatomy and health include:

• Digestive Problems: Stomach cancer can cause digestive issues such as indigestion, heartburn, nausea, vomiting, and abdominal pain. As the tumour grows, it may also prevent food from passing through the stomach, resulting in a sense of fullness after consuming small amounts of food.
• Weight Loss: Unexplained weight loss is a common symptom of stomach cancer. This can occur for several reasons, including a loss of appetite, difficulty swallowing, or malnutrition due to the cancer's impact on the digestive process.
• Anaemia: Stomach cancer can cause bleeding in the stomach, leading to a condition called anaemia. Anaemia occurs when the body does not have enough red blood cells to carry oxygen to the body's tissues. Symptoms of anaemia can include fatigue, weakness, dizziness, and shortness of breath.
• Perforation: In advanced cases of stomach cancer, the tumour can penetrate the stomach wall, leading to a hole or perforation. This can cause abdominal pain, nausea, vomiting, and fever. Perforation is a medical emergency that requires immediate treatment.
• Spread to other Organs: If stomach cancer is not treated, it can spread to other parts of the body, such as the liver, lungs, or bones. This can lead to serious health complications and a reduced chance of survival.

In addition to the physical impact, stomach cancer can significantly impact a person's emotional well-being. The uncertainty and fear associated with a cancer diagnosis can cause anxiety, depression, and other mental health issues.

Types of Stomach Cancer

The type of stomach cancer you have is based on the type of cell where your cancer began. These include:

• Adenocarcinoma: The most common type of stomach cancer, accounting for around 95% of cases. It starts in the glandular cells that line the stomach.
• Lymphoma: This type of stomach cancer starts in the immune system cells in the stomach lining.
• Gastrointestinal stromal tumour (GIST): This is a rare type of stomach cancer that develops in the cells that control the stomach muscles.
• Carcinoid tumour: This is a rare type of stomach cancer that develops in the hormone-producing cells in the stomach lining.

Who is Most at Risk for Stomach Cancer?

Stomach cancer is more common in people over the age of 50. Other risk factors for stomach cancer include:

• Family history of stomach cancer
• Previous stomach surgery
• Helicobacter pylori infection (a type of bacteria that can cause stomach ulcers)
• Smoking
• Obesity
• A diet high in smoked, salted, or pickled foods
• Exposure to certain chemicals, such as asbestos or coal dust
• Certain ethnicities, including Asians, Hispanics, Blacks

Causes of Stomach Cancer

The exact cause of stomach cancer is unknown, but certain factors can increase the risk of developing the disease. One of the main risk factors for stomach cancer is an infection with Helicobacter pylori (H. pylori), a type of bacteria that can cause inflammation in the stomach lining. Other factors that can increase the risk of stomach cancer include smoking, a diet high in salt and preservatives, and a family history of the disease.

Symptoms of Stomach Cancer

The symptoms of stomach cancer can be vague and nonspecific, making it difficult to diagnose the disease in its early stages. Some common symptoms of stomach cancer include:

• Indigestion or heartburn
• Loss of appetite
• Abdominal pain or discomfort
• Nausea and vomiting
• Difficulty swallowing
• Fatigue
• Unexplained weight loss
• Feeling full after eating small amounts of food
• Blood in the stool or vomit

Note that other medical conditions can also cause these symptoms. It is important to consult your doctor if you experience any of these symptoms.

Stomach Cancer Prevention

While some risk factors for stomach cancer, such as age and family history, cannot be changed, there are several steps you can take to reduce your risk of developing the disease.

• Eat a Healthy Diet
• Avoid Tobacco and Alcohol
• Get Screened for H. pylori
• Maintain a Healthy Weight
• Practise Good Food Safety
• Consider a screening endoscopy if risk factors present

What are the Stages of Stomach Cancer?

Stomach cancer is staged based on how far the cancer has spread. The stages of stomach cancer are:

• Stage 0: The cancer is only present in the stomach's inner lining.
• Stage I: Cancer has spread beyond the stomach's inner lining and into the muscle layer.
• Stage II: Cancer has spread into the stomach's outer layer and nearby lymph nodes.
• Stage III: Cancer has spread to nearby organs or lymph nodes but not to distant sites.
• Stage IV: Cancer has spread to distant organs like the liver or lungs.

What is Stomach Cancer Staging?

Staging is the process of determining how advanced a cancer is and how far it has spread. In the case of stomach cancer, staging involves determining the size and location of the tumour and whether it has spread to nearby lymph nodes or other organs.

The most commonly used system for staging stomach cancer is the TNM system, which stands for Tumour, Node, and Metastasis. The TNM system uses three key factors to determine the stage of the cancer:

• Tumour (T): This factor describes the size and location of the primary tumour. The T stage ranges from 0 to 4, with higher numbers indicating a larger or more invasive tumour.
• Node (N): This factor describes whether the cancer has spread to nearby lymph nodes. The N stage ranges from 0 to 3, with higher numbers indicating more lymph node involvement.
• Metastasis (M): This factor describes whether the cancer has spread to other body parts, such as the liver or lungs. The M stage is either 0 (no metastasis) or 1 (metastasis present).

How is Stomach Cancer Diagnosed?

There are several methods used to diagnose stomach cancer. These include:

• Endoscopy: A procedure in which a thin, flexible tube with a camera is inserted into the stomach through the mouth to examine the stomach's lining.
• Biopsy: During an endoscopy, a small tissue sample can be examined under a microscope to confirm the presence of cancer cells.
• Imaging tests: These tests, such as CT scans, PET scans, and MRIs, can determine the extent of the cancer and whether it has spread to other parts of the body.

How can Stomach Cancer be Treated?

The treatment options for stomach cancer depend on the stage and extent of the cancer and the person's overall health. The main treatments for stomach cancer are:

• Endoscopy: Early gastric cancer can be potentially cured with endoscopic resection (EMR or ESD)
• Surgery: Removing part or all of the stomach. If the cancer has spread to other organs, such as the liver or lymph nodes, those may also need to be removed.
• Chemotherapy: Use of drugs to kill cancer cells. Chemotherapy may be given before or after surgery to shrink the tumour or destroy any remaining cancer cells.
• Radiation therapy: Using high-energy X-rays or other types of radiation to kill cancer cells.

For small cancers that have not spread, endoscopic resection or stomach surgery (Gastrectomy) to remove the affected part of the stomach is the most effective treatment. For larger cancers that have not spread, outcomes of stomach surgery are improved if chemotherapy can be given before and after a stomach operation. When stomach cancer has spread, these treatments aim to prolong life and control symptoms:

• Chemotherapy
• Radiotherapy
• Stomach surgery (Gastrectomy)
• Endoscopic stenting

Stomach Cancer Surgery

Surgery is often the primary treatment option for stomach cancer, and it involves removing part or all of the stomach.

Stomach Cancer Surgery Preparation

Your doctor will perform a series of tests and evaluations to determine the best course of treatment. These may include:

• Physical exam and medical history review
• Blood tests
• Imaging tests, such as X-rays, CT scans, or MRIs
• Endoscopy, which involves using a long, thin tube with a camera to examine the inside of the stomach
• Biopsy, which involves taking a tissue sample for examination under a microscope to confirm the presence of cancer cells

During Stomach Cancer Surgery

Stomach cancer surgery is typically performed under general anaesthesia, which means you will be unconscious. The surgery can take several hours, depending on the extent of the cancer and the type of surgery being performed.

After making an incision in the abdomen, your surgeon will remove part or all of the stomach and any nearby lymph nodes or other tissues that may be affected by cancer. Your surgeon will then reconstruct the digestive tract to allow food to pass through the body.

After Stomach Cancer Surgery

After surgery, you will be taken to a recovery room to be monitored for any complications or side effects. Depending on the extent of the surgery, you may need to stay in the hospital for several days to several weeks to allow time for healing and recovery.

During this time, you may experience pain or discomfort, fatigue, and other symptoms. Your doctor will provide detailed instructions on managing these symptoms, including medication, diet modifications, and physical therapy.

Stomach Cancer Prognosis

The treatment of stomach cancer is personalised to each patient, and the outcomes are different for each patient. The prognosis depends on the stage of your cancer, your general fitness and the treatments you undergo. The best outcomes are seen for small tumours and those which have not spread. Survival can only be predicted after stomach surgery.

The survival rate for patients with very small tumours that have not spread is between 70-80% at five years. Larger tumours, or those that have spread to the surrounding lymph glands, have a survival rate of between 25-60% at five years.

What if Stomach Cancer is Untreated?

If left untreated, stomach cancer can spread to other parts of the body, such as the liver, lungs, and bones. This can lead to serious health complications, such as:

• Malnutrition: As cancer grows, it can make it difficult for the stomach to digest food, leading to malnutrition and weight loss.
• Perforation: If cancer penetrates the wall of the stomach, it can cause a hole to form, leading to an infection in the abdominal cavity
• Obstruction: Cancer can block the stomach or intestines, preventing food and fluids from passing through.
• Bleeding: Cancer can cause bleeding in the stomach or intestines, leading to anaemia or haemorrhage.