Stomach Cancer (Gastric Cancer)

Introduction to Stomach Cancer

Stomach cancer, also referred to as gastric cancer, occurs when cells in the stomach lining start growing abnormally and out of control. Although it frequently develops slowly over many years, it can be challenging to diagnose in its initial stages since symptoms are nonspecific or lacking. This in-depth guide is designed to offer valuable information regarding stomach cancer, from the first signs and symptoms, causes and risk factors to the different types, diagnostic tests, staging techniques, and available treatments, including surgery, chemotherapy, and newer treatments.

We will also discuss the outlook (prognosis) for those diagnosed with the disease, prevention measures, and life during and after treatment. Knowing these elements is essential to patients, families, and anyone seeking information about this significant health issue.

Types of Stomach Cancer

There are various types of stomach cancer:

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Adenocarcinomas

More than 95% of stomach cancers, known as adenocarcinomas, develop in the cells of the stomach lining. These cancers develop from the gland cells in the mucosa (the innermost lining of the stomach). Further, there are two main types of stomach adenocarcinomas: The intestinal type, in which the cancer cells are more likely to have specific gene changes that might be treated with targeted drug therapy, and the diffuse type, which tends to spread more quickly and is less common than the intestinal type.

Other less common types of stomach cancer are:

Lymphoma of the stomach: It develops in the lymphatic tissue (tissue that drains away fluid and helps fight infection) and lymphocytes (immune system cells).

Gastrointestinal stromal tumors (GISTs): These develop in the muscle or connective tissue of the stomach wall. Some GISTs are much more likely than others to grow into other areas or spread to different parts of the body.

Neuroendocrine tumors (including carcinoids): These tumors are initiated in the stomach cells or other parts of the digestive tract. In some ways, they act like nerve cells, and in different ways like hormone-making cells.

Other very rare types of stomach cancer include squamous cell carcinomas, leiomyosarcomas, and small cell carcinomas.

Symptoms & Signs of Stomach Cancer

The stomach cancer symptoms vary at early and later stages and are as follows:

Stomach Cancer Symptoms at Initial Stage: The stomach cancer early symptoms are as follows:

• persistent indigestion and heartburn
• trapped wind and frequent burping
• feeling very full or bloated after meals
• persistent stomach pain
• pain in your stomach or breastbone
• difficulty swallowing (dysphagia)

Stomach Cancer Symptoms at Advanced Stage:

• blood in your stools, or black stools
• loss of appetite
• weight loss
• tiredness
• swelling or lumpiness in your stomach
• anaemia
• jaundice

The specific part of the stomach where cancer develops can influence both the symptoms a person experiences and their overall prognosis. A significant challenge is that early-stage stomach cancer is often asymptomatic. Furthermore, when early symptoms do occur, they tend to be nonspecific (like indigestion or mild discomfort) and closely resemble common ailments. Because these initial signs are so easily mistaken for less serious issues, it’s difficult for individuals to recognise the potential danger, frequently resulting in delayed diagnosis until later stages.

Causes and Risk Factors

It is not yet clear how the cells in the stomach become cancer cells, but there are possible causes and associated risk factors for stomach cancer.

Potential Stomach Cancer Causes

Stomach cancer arises from harmful DNA mutations in stomach lining cells, causing uncontrolled growth. Helicobacter pylori (H. pylori) infection, pre-cancerous changes in the stomach lining, and genetic changes (DNA mutations) are considered the major causes of stomach cancer.

The most significant risk factor is chronic infection with Helicobacter pylori (H. pylori) bacteria, which causes persistent inflammation (gastritis). This long-term damage can lead to pre-cancerous conditions like atrophic gastritis (loss of normal stomach glands) and intestinal metaplasia (stomach lining replaced by intestinal-type cells), eventually progressing to dysplasia (highly abnormal cells).

These conditions increase cancer susceptibility. Other crucial factors contributing to the necessary DNA damage include smoking and potentially dietary components (like those high in salt or nitrates, which certain H. pylori strains might convert into carcinogens). Most cancer-causing DNA mutations are acquired, while less common (1-3% of cases), inherited genetic syndromes like Hereditary Diffuse Gastric Cancer (HDGC) also significantly elevate risk. Often, stomach cancer develops gradually due to the combined effect of these factors over many years.

Associated Risk Factors

People who are more likely to be at risk:

• are men
• are 55 years of age or older
• smoke
• have a low fibre diet and high in processed food or red meat
• have a diet that contains a lot of salted and pickled foods
• have a medical condition, such as pernicious anemia, peptic stomach ulcer or hypertropic gastropathy
• who consume alcohol (more than three drinks per day)
• have a medical history of any stomach surgery
• have inherited cancer syndromes, such as hereditary diffuse gastric cancer, lynch syndrome, Li-Fraumeni syndrome or Peutz-Jeghers syndrome
• who are involved in certain occupations, such as workers in the coal, metal and rubber industries

It’s important to remember that having one or even several risk factors does not mean someone will definitely develop stomach cancer. However, awareness of these factors can help in understanding personal risk and potentially making lifestyle changes where possible.

Stomach cancer can be spread directly or through the lymphatic system or the blood.

Diagnosis of stomach cancer

Diagnosing stomach cancer involves a combination of tests to confirm the presence of cancer, determine its exact location, and understand how far it may have spread (its stage). The following are stomach cancer diagnostic tests:

• Blood tests: These are done to check for issues associated with stomach cancer (low red blood cells, possibly from tumor bleeding), assess overall organ function, and, occasionally, for specific tumor markers.
• X-ray/barium meal X-ray: In this method, a patient swallows a chalky liquid (barium) that coats the stomach lining, allowing abnormalities like tumors or ulcers to show up more clearly on X-ray images. This is used less often now than endoscopy.
• Endoscopy (Upper Endoscopy or Gastroscopy): This is the primary test for detecting stomach abnormalities. A thin, flexible tube with a light and camera (endoscope) is passed down your throat to visualise the internal lining.
• Endoscopic ultrasound (EUS): This uses an ultrasound probe attached to the endoscope tip to create detailed images showing how deeply a tumor has penetrated the stomach wall. It also helps assess nearby lymph nodes for cancer spread.
• Biopsy: During an endoscopy, small tissue samples are taken from suspicious-looking areas in the stomach lining. This is essential for a definitive diagnosis and includes testing for other gene or protein changes.
• Magnetic resonance imaging (MRI) scan: MRI uses strong magnets and radio waves to create detailed images, particularly useful for evaluating soft tissues.
• Positron emission tomography (PET) scan: Often combined with a CT scan (PET-CT), this test uses a radioactive sugar tracer to highlight areas of high metabolic activity, like cancer cells.
• Computerised tomography (CT) scan: This is crucial for staging, as it shows the tumor size and assesses its spread to lymph nodes, liver, lungs, or other distant sites.
• Liver ultrasound scan: This imaging test uses sound waves specifically to check for signs of cancer spread (metastases) within the liver. It can be performed externally or sometimes during a laparoscopy.
• Laparoscopy: A minimally invasive surgical procedure done before planning treatment to directly view the outside of the stomach and nearby organs and determine if the cancer has spread (staging).
• Sentinel lymph node biopsy (SLNB): Sometimes performed during surgery, this involves identifying and removing the first few lymph nodes (“sentinels”) where cancer is most likely to spread. Examining these nodes helps accurately determine the extent of lymph node involvement.

Grading and Staging of Stomach Cancer

The layers of the stomach play a crucial role in determining the stomach cancer. The stage becomes more advanced as the tumor grows from the mucosa into deeper layers.

Staging

Stomach cancer staging determines the extent of cancer spread, guiding treatment and prognosis. The primary method is the AJCC TNM system, which assesses T (tumor: how deep it penetrates the stomach wall), N (Nodes: involvement of nearby lymph nodes), and M (Metastasis: spread to distant sites).

The stomach cancer stages are as follows:

• Stage 0: The earliest stage (carcinoma in situ), where cancer cells are confined to the innermost stomach lining (mucosa) only.
• Stage I: Cancer has invaded deeper layers (like submucosa or muscle) but involves few or no lymph nodes and has not spread distantly.
• Stage II: The tumor grows deeper into the stomach wall (potentially reaching outer layers) and/or involves more lymph nodes, but still no distant spread.
• Stage III: Cancer significantly invades the stomach wall (possibly reaching nearby structures) and/or involves many lymph nodes but remains confined regionally.
• Stage IV: The most advanced stage, where cancer has metastasised to distant organs like the liver, lungs, or distant lymph nodes.

Doctors determine a clinical stage before treatment using tests and imaging, while a more precise pathological stage is determined after surgery by examining the removed tissues.

Grading

Grading describes how quickly it is likely to spread in the future.

There are 3 grades of stomach cancer:

• Low-grade – the cancer tends to grow slowly
• Medium-grade – the cancer grows a bit faster
• High-grade – the cancer is aggressive and likely to grow quickly

Treatment Options of Stomach Cancer

Stomach cancer treatment is highly personalised, depending significantly on the cancer’s stage, location, specific characteristics, and the patient’s overall health. A multidisciplinary team of specialists collaborates to determine the optimal treatment plan, often involving a combination of approaches. The stomach cancer medical procedures aims to cure the cancer when possible (typically in earlier stages) or to control its growth, relieve symptoms, and maintain quality of life in more advanced cases.

The stomach cancer treatment options are as follows:

Surgery

It is a cornerstone of stomach cancer treatment done for complete removal of the tumor along with a margin of healthy tissue and nearby lymph nodes, as cancer often spreads there first. The extent of surgery procedure, such as Surgical procedures performed, can be partial gastrectomy (a portion of the stomach is removed), total gastrectomy (entire stomach is removed) and oesophagogastrectomy (entire stomach plus the lower part of the esophagus is removed).

Chemotherapy

It utilises cytotoxic drugs, typically intravenously or orally, that circulate throughout the body to kill rapidly dividing cancer cells. The therapy can be given to shrink the tumor, eliminate any remaining microscopic cancer cells, and reduce the risk of recurrence. In case of advanced or metastatic cancer (Stage IV), the therapy is done to control tumor growth, alleviate symptoms, and potentially extend survival.

Radiotherapy

It employs high-energy radiation beams to destroy cancer cells. Its use in stomach cancer is more limited than surgery or chemotherapy due to the potential for damage to nearby sensitive organs. However, it can be given post-surgery to reduce the recurrence risk.

Targeted Therapy

These therapy drugs work by explicitly identifying and attacking molecules involved in cancer growth, often causing less harm to normal cells. The most common target for stomach cancer is the HER2 protein.

Immunotherapy

This therapy leverages the patient’s immune system to fight cancer. Checkpoint inhibitors (e.g., pembrolizumab, nivolumab) release the brakes on immune cells, enabling them to recognise and attack cancer cells more effectively. This is primarily an option for advanced or metastatic stomach cancer.

Prognosis and Stomach Cancer Survival Rate

Prognosis

For stomach cancer, the prognosis depends heavily on several factors, the most significant being the stage of the cancer at diagnosis, meaning how far it has spread. Other important factors include:

• The specific location of the cancer within the stomach.
• The type of stomach cancer and its grade (how abnormal the cells look).
• Whether the cancer cells have specific genetic markers (like being HER2-positive).
• Whether the cancer can be completely removed with surgery (resectability).
• The person’s overall health and age.
• How well the cancer responds to treatment.

In general, the earlier stomach cancer is diagnosed and treated (lower stage), the better the prognosis. Cancers confined to the stomach lining have a much more favorable outlook than those that have spread through the stomach wall, to nearby lymph nodes, or distant organs.

Survival Rates

Survival rates provide an estimate of the percentage of people with the same type and stage of cancer who are still alive a certain amount of time (usually 5 years) after their diagnosis. For example, suppose the 5-year relative survival rate for a specific stage is 70%; it means people diagnosed with that stage of stomach cancer are, on average, about 70% as likely as people who don’t have that cancer to live for at least 5 years after diagnosis.

Stomach cancer Survival Rates by Stage:
It’s crucial to discuss specific rates with your doctor, as they depend on many individual factors. However, general trends show:

• Localized: If the cancer is confined to the stomach, the 5-year relative survival rate is significantly higher (often cited around 70% or more).
• Regional: If the cancer has spread to nearby lymph nodes or structures, the rate is lower (often cited as around 30-35%).
• Distant (Metastatic): If the cancer has spread to distant parts of the body (like the liver or lungs), the 5-year relative survival rate is much lower (often cited as around 5-7%).

Prevention

Although not all stomach cancers can be prevented, various steps can significantly reduce the risk:

• Treat H. pylori Infection
• Take a Healthy Diet
• Avoid Tobacco
• Maintain a Healthy Weight
• Avoid Alcohol
• Use NSAIDs Carefully
• Know Your Family History
• Screening Considerations

Consult the Cancer Round team to assess your risk factors and determine the most appropriate prevention strategies for you.

Living With and After Stomach Cancer

Living with and beyond stomach cancer is a process that calls for resilience and flexibility. Coping with treatment side effects such as nausea and fatigue requires good communication with your treatment team. Nutrition is of primary importance, particularly following surgery (gastrectomy), which requires smaller, more frequent, high-nutrient meals and careful eating to prevent complications such as dumping syndrome – using an oncology dietitian is strongly recommended.

Life after treatment includes ongoing follow-up care to monitor for recurrence and deal with long-term side effects as you adapt to a ‘new normal.’ Mental health is essential; accepting feelings of anxiety or fear and seeking help through therapy, groups, or support groups helps survivorship. Real concerns, such as money or work, require major attention. Maximising resources and prioritising quality of life promote hope and resilience.

Research and Clinical Trials

Continued research is key to enhancing stomach cancer prevention, diagnosis, and treatment. Researchers are studying genetic mutations that stimulate cancer growth in order to design more potent targeted treatments and immunotherapies which engage the body’s immune system to combat cancer cells. Clinical trials are vital studies that assess the safety and efficacy of these new drugs, surgical methods, radiation methods, and diagnostic tests. Clinical trial participation provides patients with access to potentially innovative treatments before they become widely available. Research into new screening techniques for earlier diagnosis and the reasons behind treatment failure are also research priorities designed to enhance outcomes for those living with stomach cancer.

Making Informed Decisions

The path through stomach cancer treatment is complex and highly individual. Open communication with medical experts is essential. Cancer Rounds assist with the recommended options, potential benefits, risks, and side effects. Considering your specific situation and preferences, get to know the stomach cancer treatment cost.

FAQs

Q1. Is stomach cancer common?

In India, stomach cancer is relatively common and a significant health concern, ranking among the leading causes of cancer-related deaths, with higher incidence in Southern and Northeastern regions. Globally, it remains an important issue and is one of the most common cancers worldwide, particularly prevalent in East Asia, though rates are lower in North America and Western Europe.

Q2. Is stomach cancer hereditary?

Most stomach cancers are not hereditary. However, a small percentage (around 1-3%) are linked to inherited genetic syndromes, like Hereditary Diffuse Gastric Cancer (HDGC), significantly increasing risk in affected families.

Q3. Can stomach ulcers turn into cancer?

Benign stomach ulcers themselves rarely become cancerous. However, chronic infection with H. pylori bacteria, a common cause of ulcers, leads to long-term stomach inflammation (gastritis), which significantly increases the risk of developing stomach cancer over time.

Q4. What’s the difference between stomach cancer and gastric cancer?

There is no difference; “stomach cancer” and “gastric cancer” are the same condition. “Gastric” is the medical term referring to the stomach, so the terms are used interchangeably by doctors and researchers.

Q5. Can you live without a stomach?

Yes, survival is possible after surgical removal of the stomach (total gastrectomy). The esophagus is connected directly to the small intestine, requiring significant lifelong dietary changes and nutritional monitoring.

Q6. How to test for stomach cancer at home?

There are currently no reliable home tests available to diagnose stomach cancer directly. Diagnosis requires medical procedures like endoscopy and biopsy performed by healthcare professionals; some home kits test for H. pylori infection (a risk factor), but not cancer itself.