Gastric cancer, also known as stomach cancer, is one of the most common and fatal malignancies globally. It occurs when cancerous cells start to develop in the stomach lining. Find out more about it below!
Epidemiology
The incidence of stomach cancer varies in different regions of the world, with the greatest occurrences in Central and East Asia. Mongolia, Japan, and South Korea are the countries known to have some of the highest prevalence within these regions.
Males are also about two times more likely to get stomach cancer compared to females.
Development of Stomach Cancer
The exact cause of the cancer is unknown, but it is known to begin when stomach cells start to grow uncontrollably and typically progresses very gradually.
Pre-cancerous changes often first occur within the innermost stomach lining before the true malignancy develops. As these initial changes rarely cause any symptoms, they usually go undetected.
Genetic mutations in stomach cells and within individuals may also contribute to the development of gastric cancer.
Risk Factors and Prevention
The following are some factors that could increase the likelihood of getting gastric cancer.
- Age: Chances tend to increase as a person gets older.
- Certain medical conditions: Helicobacter pylori infection, intestinal metaplasia, chronic atrophic gastritis, pernicious anaemia, stomach polyps (growths), Epstein-Barr virus, previous stomach surgery.
- Dietary habits: High intake of salted or smoked foods, and low consumption of fruits and vegetables.
- Environmental causes: Related to radiation exposure and certain occupations (e.g., coal, metal, and rubber industries).
- Gender: More common in men than women.
- Lifestyle: Smoking and alcohol consumption.
- Some genetic conditions: family history, type A blood, inherited cancer syndromes.
- Weight: Obese and overweight individuals are at increased risk.
Some risk factors are modifiable, while others cannot be controlled.
Altering diet, lifestyle patterns and weight, smoking cessation, limiting alcohol intake, avoiding cancer-causing elements, and having infections treated (e.g., Helicobacter pylori) can help to prevent cancer from developing.
Clinical features of stomach cancer
In the early stages, gastric cancer rarely causes any symptoms. However, when symptoms manifest, they can include:
- Lack of appetite
- Early satiety
- Unintentional loss of weight
- Abdominal pain or discomfort
- Heartburn or indigestion
- Nausea
- Vomiting (may be bloody)
- Ascites (fluid accumulation in the abdomen)
- Bloody stools
- Anaemia and fatigue
- Jaundice (yellowing of eyes and skin) from metastasis to liver
- Difficulty swallowing
Many of the symptoms could also be a result of other conditions. Hence, anyone with persisting or worsening symptoms should consult a doctor for further evaluation.
Diagnosis of stomach cancer
Below are some of the investigations that clinicians may carry out to determine if a patient has gastric cancer:
- Detailed medical history
- Physical examination
- Blood tests (e.g., blood chemistry studies, complete blood count [CBC])
- Faecal occult blood test (FOBT)
- Biopsy
- Laparoscopy
- Upper endoscopy
- Imaging tests (e.g., Endoscopic ultrasound, Barium swallow [Upper GI series], CT-scan, X-rays, MRI, PET-scan)
Some of these tests can also be used to evaluate how much the cancer has spread, and the effectiveness of treatment.
Staging
After a confirmed diagnosis, doctors will conduct examinations to find out the extent of the spread of cancer in the body. This is known as staging. It can also be used in prognostication and guide therapeutic interventions.
The most used staging system groups gastric cancer ranging from stage 0 (carcinoma in situ) to stage 4. The lower the number, the less the cancer has disseminated.
Staging can also be carried out at various points throughout a person’s therapy. Usually, the cancer is assigned an initial clinical stage based on the diagnosis and further investigations to aid in treatment planning. Then, it may be done again upon completion of an intervention (e.g., surgery, chemotherapy, radiation) to determine its effectiveness and the need for any further therapy.
Types of Stomach Cancer
Stomach cancers are classified according to the type of stomach tissue from which they grow.
Adenocarcinomas are the predominant form of stomach malignancy diagnosed that develops from the stomach’s innermost lining. It accounts for almost 90% of the cases. There are 2 main kinds:
- Intestinal: Generally have a slightly better outlook compared to the diffuse type.
- Diffuse: Less common but tends to spread more quickly and is harder to treat.
Other rarer forms of stomach cancer include some of the following:
- Gastric lymphomas: Cancer of the immune system tissue within the stomach.
- Gastrointestinal stromal tumours (GISTs): Develop from cells in the stomach wall. Tumours may be benign or malignant.
- Carcinoid tumours: Rare, slow-growing cancerous tumours originating from cells in the nervous system and endocrine system.
Treatment
Therapeutic options are affected by the location of gastric cancer. Some of the main approaches to treatment are:
- Surgery
- Endoscopic mucosal resection
- Chemotherapy
- Targeted drug therapy
- Immunotherapy
- Radiation therapy
The choice of therapy depends on the severity and patient demographics. A combination of treatment methods may also be employed [13].
Prognosis
A patient’s chance of recovery depends on the gravity of cancer as well as the patient’s overall health status.
Typically, the earlier the cancer is discovered, the better the outcome. However, gastric malignancies tend to be in the later stages when discovered as they are often asymptomatic in the early phases. At advanced stages, cancer can be treated but not cured, and survival rates are lower as well.
