Introduction

Stomach cancer, also called gastric cancer, is a tumour that develops in the innermost lining of your stomach.¹ It remains a global health challenge despite a decline in incidence and mortality rates over the last 10 years. It is most commonly diagnosed in people living in Asian, Central and Eastern European, and South American countries. GI cancer cases have been few in the UK and the US in the past decade.²

A person can prevent stomach cancer by taking precautions and maintaining a healthy lifestyle.

In this article, we will discuss stomach cancer, its signs and symptoms, causes, and ways to prevent it, and live a healthy life.

What is stomach cancer?

Stomach cancer occurs when stomach cells undergo abnormal division. The oesophagus connects our mouth to our stomach. The junction at which these two combine is called the Gastroesophageal junction or GE.³ The food we eat passes through the oesophagus and reaches our stomach.

The stomach has the following 5 layers:³

• Mucosa: the innermost layer that produces HCl and Pepsin(gastric juices). Most stomach cancers develop here and move towards the outer layers
• Submucosa: the supporting layer
• Muscularis propria: a muscular layer that mixes the food contents
• Subserosa: part of the outer layer
• Serosa: the outermost layer

These layers are important as they help in determining the extent of stomach cancer, how much it has spread, and according to that, your treatment is planned.

Signs and symptoms of stomach cancer

Signs and symptoms to look out for: 

• Difficulty swallowing food
• Abdominal pain
• Indigestion
• Feeling full after eating very little food
• Not feeling hungry at meal times
• Bloating after eating
• Weight loss without any apparent reason
• Heartburn
• Nausea
• Vomiting
• Lethargic (feeling tired)
• Black colored stools

Many patients do not develop any of the above symptoms in the early stages of their cancer. However, some may report pain in their abdominal area without any cause.When stomach cancer spreads to other body organs, it is known as metastatic gastric cancer. When it metastasises to the lymph nodes, it causes them to swell, resulting in lumps in the abdomen. When it spreads to the liver, it causes symptoms like jaundice (pale skin and yellowish eyes).

What are the causes of stomach cancer?

Stomach cancer occurs when cells undergo abnormal changes in their DNA repair process.⁵ 

Factors that contribute to these changes are:⁴

• H. pylori infection
• Processed foods and foods high in salt
• Red meat 
• Tobacco smoking 
• Workers in the coal and rubber industry
• Radiation exposure
• Gastroesophageal reflux disease (GERD)
• Chronic atrophic gastritis
• Chronic atrophic gastritis with intestinal metaplasia
• Epstein-Barr virus infection
• Pernicious anemia 
• Older age
• Family history of stomach cancer
• Obesity 
• Men are more at risk than women, especially black men

Gastritis caused by H. pylori can increase your chances of developing cancer in the middle and lower parts of your stomach. In contrast, obesity and GERD increase the chances in the upper part.⁴ 

Certain genetic conditions also increase the risk of this malignancy:⁴

• Familial adenomatous polyposis
• Familial intestinal gastric cancer
• Gastric adenocarcinoma
• Juvenile polyposis syndrome
• Hereditary diffuse gastric cancer
• Li-fraumeni syndrome
• Peutz-Jeghers syndrome
• Lynch syndrome 

If the tumour is present within the walls of your stomach, its prognosis is good. But if it has spread to other regions, it becomes difficult to cure. Many stomach cancers are not diagnosed early because of the lack of early signs. If you have the above signs and symptoms, consult a doctor. 

How to prevent stomach cancer?

You can prevent GI cancer by changing your eating habits and lifestyle. The following measures can be taken:

Incorporate a healthy diet

Eating a healthy diet daily makes a key difference in your gut health.⁵

• Eat fibre-rich fruits and green vegetables
• Consume a diet rich in Vitamin C, such as citrus fruits
• Avoid eating processed foods and foods high in iodine
• Reduce the intake of pickles and smoked foods in your diet
• Whole grains, plant-based meals, carotenoid foods, e.g, carrots, sweet potatoes, butternut squash, kale, spinach, pumpkin, bell peppers, and tomatoes

Avoid tobacco and alcohol

There is a strong link between tobacco smoking and gastric cancer. People who smoke tobacco daily are at a much higher risk than people who have quit smoking.⁵

If you take 3 or more alcoholic drinks daily, you are at a much higher risk of developing stomach cancer!

Alcohol irritates your gut lining. It causes changes in the cell DNA repair mechanism by producing acetaldehyde. Alcohol also produces oxygen molecules that are free radicals, and they cause damage to the organelles of your cells. As such, alcohol is a major cause of developing gastric cancer.^6,7

Stomach cancer depends more on the amount of alcohol than its type.⁷

Men should limit their alcohol intake to 2 drinks per day, and women should limit it to 1 because their bodies are smaller and take longer to break down alcohol. To prevent gastric cancer, avoid both smoking and alcohol.⁶

Treat H. pylori infection

H. pylori is a gram-negative, flagellated bacterium that commonly causes gut infections in humans.⁸ Chronic infection of H. pylori is the cause of adenocarcinoma in the distal part of the stomach.⁸ Treating H. pylori infection early reduces the risk of developing GI cancer.

H. pylori usually affects children and causes peptic ulcers. It can be transmitted to you when you come into contact with a person infected with it through saliva, stool, or vomit. It can also cause infection by drinking contaminated water and eating unhygienic food. Your doctor will prescribe you antibiotics and indigestion-relieving medications to treat the infection.

To prevent H. pylori infection:

• Prepare your food with clean water
• Drink water from clean sources
• Wash your hands before eating
• Don’t eat at unhygienic places
• Get yourself treated for peptic ulcers as soon as possible

Go for regular screening and medical checkups

Regular screening can help prevent stomach cancer. People with the following conditions should get themselves checked regularly:⁹

• Persistent H. pylori infections
• Positive family history of stomach cancer
• Older men and women above 60 
• Obese men and women
• Living in high-risk regions 
• People suffering from the aforementioned genetic diseases

 It is better to go for screening if you suffer from the above conditions. Your doctor will first take your complete medical history and then proceed with a physical exam to check for a lump in your abdomen.

These are the diagnostic tools used to screen and diagnose stomach cancer:

• Upper Endoscopy: most commonly used for diagnosing stomach cancer. A thin tube is placed in the mouth that reaches your stomach. It has a thin camera, and small surgical instruments are passed if a biopsy is needed
• Endoscopic Ultrasound: a procedure that combines both endoscopy and ultrasound to stage cancer and take pictures of your stomach
• Radiologic tests: MRI, barium swallow, and CT scan are all helpful in diagnosing stomach cancer
• PET scan: This scan will tell your doctor whether the cancer has spread to other organs or not
• Laparoscopy: It is a surgical procedure performed when other less invasive procedures don't provide sufficient information on the cancer

Cancer tumours are classified through staging. Stage 0 means the cancer has not spread, and the prognosis is good. In stage 4 cancer, the cancer has spread to other organs and becomes difficult to treat.

Regular medical check-ups and screening are not done for stomach cancer in the UK, because it is comparatively rare. However, if you suffer from any of the above conditions, you should consult a doctor.

Maintain a healthy lifestyle

Gastric cancer can be prevented by maintaining a healthy lifestyle. This includes the following practices:¹⁰

• Regular walks
• Moderate exercise
• Weight management

Since obesity is a risk factor, you can prevent stomach cancer by eating healthy.

Stress alone cannot cause stomach cancer, but it may increase your chances of getting it.¹¹ Chronic stress causes suppression of your immunity, increases your cortisol, and leads to unhealthy habits of drinking alcohol, smoking, and eating on impulse.¹¹ Hence, it is very important to regulate your stress levels.

Some tips that reduce stress:¹¹

• Follow a routine that suits you
• Practice gratitude 
• Journaling and mindful meditation
• Exercise regularly
• Maintain a healthy diet
• Seek professional help

Role of education and awareness in preventing stomach cancer

We can prevent GI cancer in a high-risk population by the following methods:¹²

• Regular screening
• Medical checkups 
• Raising awareness by educating the public

Screening programs and public education are ways to prevent stomach cancer in countries at high risk.

Summary

Stomach cancer, or GI cancer, is a tumour that develops in the inner lining of the stomach. If someone suffers from persistent H. pylori infections, they should seek immediate treatment. We can diagnose GI cancer easily by using various diagnostic tests, and its prognosis is usually good in patients who undergo treatment. However, early diagnosis is key in appropriately managing this malignancy and preventing the spread of the cancer. 

High-salt diet, processed foods, drinking alcohol, and tobacco smoking increase your chances of getting GI cancer in your life. By making small changes and slowly eliminating these risk factors, you can reduce the risk of developing gastric cancer.