Stomach Cancer (Gastric Cancer): Comprehensive Health Information

This information is provided by SSCHRC to help you understand stomach cancer and its management. It is written in a patient-friendly and medically accurate style.

1. General Information

Stomach cancer, also known as gastric cancer, is a type of cancer that is relatively uncommon but can be serious. As its early symptoms often mimic common, less serious issues such as indigestion or heartburn, the disease is sometimes not detected until it has reached an advanced stage, which can lead to poorer outcomes.

The term 'stomach' in a medical context refers specifically to the muscular, sac-like organ in the upper abdomen. This organ receives food from the oesophagus (food pipe) and mixes it with gastric juices to begin the digestive process.

Stomach cancer develops when cells within the stomach's inner lining begin to divide and grow uncontrollably, forming a tumour. As the cancer progresses, this tumour can invade and damage nearby tissues, block the passage of food, or break away and spread (metastasise) to other organs.

Globally, most stomach cancer cases develop in the main part of the stomach, known as the body. It can also occur in the distal stomach, near where the stomach meets the small intestine. In some regions, cancers affecting the gastroesophageal junction (cardia), where the stomach connects to the oesophagus, are becoming more frequent.

Stomach Cancer Types

The type of stomach cancer depends on the cell in which it originates. The main types include:

Adenocarcinomas

These are the most common type, making up about 90% of all stomach cancer cases. They begin in the mucosal (inner) layer of the stomach lining and grow outwards, invading the other layers of the stomach wall.

Gastrointestinal Stromal Tumours (GIST)

This cancer affects a specific type of cell (Interstitial cells of Cajal) in the gastrointestinal tract, most often in the stomach or small intestine. They are sometimes referred to as gastric sarcomas.

Carcinoid Tumours

Also known as neuroendocrine tumours, these affect the hormone-producing cells of the stomach.

Stomach Cancer Statistics

According to cancer registry estimates, about 60,000–65,000 new cases of stomach (gastric) cancer are diagnosed in India each year, most commonly in older adults, and the overall five-year survival rate is generally lower than in Western countries due to many cases being diagnosed at a later stage, which can negatively affect outcomes.

Stomach Cancer Risk Factors

While the exact cause remains unknown, certain factors are known to increase the risk of developing stomach cancer. These include:

Demographic Factors

  • • Gender: The majority of patients diagnosed with stomach cancer are male.
  • • Age: Most individuals who develop stomach cancer are over 55; the median age at diagnosis is 68 years old.
  • • Geography: The disease is more prevalent in countries such as Japan, China, Southern and Eastern Europe, and Central and South America.

Lifestyle & Environmental Factors

  • • Infection with Helicobacter pylori (H. pylori)
  • • Exposure to Chemicals (rubber, metal, coal, timber industries, asbestos)
  • • Obesity
  • • Tobacco and Alcohol Abuse
  • • Diet and Food Preservation (salted, pickled, dried foods, nitrates)

Medical Conditions

  • • Pernicious anaemia
  • • Chronic stomach inflammation (gastritis) and intestinal polyps
  • • Acid reflux or chronic indigestion
  • • Menetrier disease
  • • Epstein-Barr virus infection
  • • A history of stomach lymphoma
  • • Type A blood
  • • Previous stomach surgery

Family History

Stomach cancer is rarely passed down genetically. However, having close relatives with stomach cancer or a hereditary cancer syndrome, such as Hereditary Diffuse Gastric Cancer syndrome (caused by CDH1 mutation), hereditary non-polyposis colon cancer (HNPCC), or Li-Fraumeni syndrome, may increase personal risk. Genetic testing may be used to identify a genetic predisposition.

Important Note: It is important to remember that not everyone with these risk factors will develop stomach cancer. If you have concerns about your risk factors, please discuss them with your doctor.

2. Symptoms

Early-stage stomach cancer is often asymptomatic. When symptoms do appear, they are frequently mistaken for less serious digestive problems, which is why the cancer may not be diagnosed until it is advanced.

Potential Symptoms

  • • Abdominal pain or discomfort
  • • Loss of appetite
  • • Indigestion, heartburn, or ulcer-like symptoms
  • • Nausea and vomiting
  • • Bloating or swelling in the abdomen
  • • Diarrhoea or constipation
  • • Feeling full after eating only a small amount of food
  • • Bloody or black stools
  • • Fatigue
  • • Unintentional weight loss

Important Note: Experiencing these symptoms does not automatically mean you have stomach cancer. However, if any of these signs persist for more than two weeks, you should consult your doctor.

3. Diagnosis

Stomach cancer can be difficult to diagnose, especially early on, because initial symptoms are often vague or non-existent until the disease has progressed. Early and accurate diagnosis is crucial for successful treatment and better patient outcomes.

If your doctor suspects stomach cancer based on your symptoms, they will conduct an examination and ask about your health, lifestyle (including smoking and drinking habits), and family medical history. One or more of the following tests may be used for diagnosis, staging, or monitoring treatment effectiveness:

Blood Tests

While no single blood test can definitively diagnose stomach cancer, tests can provide important health indicators. A complete blood count (CBC) can check for anaemia, which may signal internal bleeding from the tumour. Doctors may also check for tumour markers, such as cancer antigen 125 (CA-125) and carcinoembryonic antigen (CEA), which are sometimes produced by cancerous cells.

Fecal Occult Blood Test

A stool sample is examined for tiny, invisible traces of blood, which can suggest bleeding within the stomach.

Upper Endoscopy

A thin, flexible tube called an endoscope, fitted with a camera, is inserted through the mouth, down the oesophagus, and into the stomach. This allows the doctor to visually inspect the stomach lining for signs of cancer. The endoscope may also be equipped with a tool to remove tissue samples (biopsy).

Biopsy

This involves removing a small amount of tissue for examination under a microscope to confirm the presence of cancer cells. For stomach cancer, biopsies are usually performed during an endoscopy.

Endoscopic Ultrasound

An endoscope equipped with a small ultrasound device is inserted into the stomach. The ultrasound creates images of the stomach wall using sound waves, helping the doctor assess how deeply the cancer has invaded the walls or check for pre-cancerous changes.

Imaging Tests

These scans allow doctors to see the inside of the abdomen and stomach, helping to confirm the tumour's location and check if the cancer has spread to nearby organs. Common imaging tests include:

  • • CT or CAT (computed axial tomography) scans
  • • PET (positron emission tomography) scans
  • • MRI (magnetic resonance imaging) scans
  • • X-rays (also called an upper GI (gastrointestinal) series)

Staging Laparoscopy

This is a minimally invasive procedure performed under general anaesthesia to determine the extent of the disease. A thin tube with a camera is inserted into the abdominal cavity, allowing doctors to inspect the abdominal organs for signs of cancer spread. A saline solution may also be used to 'wash' the abdominal cavity (peritoneum washing); the fluid is then analysed for cancer cells. This can detect cancer not visible on other scans.

Stomach Cancer Staging

Cancer staging describes the size of the primary tumour and how far the cancer has spread within the body. Knowing the stage is vital for the care team to develop an appropriate treatment plan and helps determine the patient's prognosis.

TNM Staging System

The internationally recognised TNM system describes cancer based on three main factors, each assigned a number to reflect the extent of the disease:

  • T (Tumour): The size of the primary tumour and whether it has invaded nearby tissues. (Scored T1–T4)
  • N (Nodes): The spread of the cancer to nearby lymph nodes. (Scored N1–N3)
  • M (Metastasis): Whether the cancer has metastasised (spread) to distant parts of the body. (Scored M0–M1)

After all staging procedures are complete, your doctor will determine the TNM stage and explain how it impacts your treatment and prognosis.

Simplified Stages (0 to IV)

The TNM classification is often simplified into four main stages (I–IV), with some cancers also having a Stage 0. Higher numbers indicate more advanced cancer that is generally more challenging to treat.

Stage 0

Reflects abnormal cells found only in the mucosa (carcinoma in situ) that have not spread to nearby normal tissue. This is considered pre-cancerous.

Stage I

Cancers are typically small and confined to the area where they began.

  • Stage IA: Cancer has formed in the mucosa and may have spread to the submucosa.
  • Stage IB: Cancer has formed in the mucosa and may have spread to the submucosa and 1 or 2 nearby lymph nodes; or cancer has formed in the mucosa and has spread to the muscle layer.

Stage II

Cancers have spread to nearby tissue and/or lymph nodes.

  • Stage IIA: Cancer may have spread to the submucosa and 3 to 6 nearby lymph nodes; or to the muscle layer and 1 or 2 nearby lymph nodes; or has spread to the subserosa.
  • Stage IIB: Cancer may have spread to the submucosa and 7 to 15 nearby lymph nodes; or to the muscle layer and 3 to 6 nearby lymph nodes; or to the subserosa and 1 or 2 nearby lymph nodes; or has spread to the serosa.

Stage III

Cancers have spread more extensively to nearby tissue and/or lymph nodes.

  • Stage IIIA: Cancer has spread to the muscle layer and 7 to 15 nearby lymph nodes; or to the subserosa and 3 to 6 nearby lymph nodes; or to the serosa and 1 to 6 nearby lymph nodes; or has spread to nearby organs (e.g., spleen, colon, liver, pancreas).
  • Stage IIIB: Cancer may have spread to the submucosa or muscle layer and 16 or more nearby lymph nodes; or to the subserosa or serosa and 7 to 15 nearby lymph nodes; or to nearby organs and 1 to 6 nearby lymph nodes.
  • Stage IIIC: Cancer has spread to the subserosa or serosa and 16 or more nearby lymph nodes; or to nearby organs and 7 or more nearby lymph nodes.

Stage IV

Cancer has spread to distant areas of the body (metastatic cancer), such as the lungs, liver, distant lymph nodes, and the abdominal lining. Stage IV cancer often cannot be cured but can frequently be managed like a chronic disease.

4. Treatment

At SSCHRC, we believe in a customised approach to stomach cancer treatment, aiming for the highest chances of success while prioritising your quality of life. Our comprehensive treatments include state-of-the-art surgery, advanced radiation therapy, chemotherapy, targeted therapy, and immunotherapy.

Treatment plans for stomach cancer often involve a combination of therapies. A dedicated team of specialists, including oncologists, radiation oncologists, and surgeons, works collaboratively to determine the most effective plan for each patient. This integrated approach, supported by advanced skill and technology, ensures you receive the best possible care with minimal impact on your body.

Your recommended treatment will depend on several factors, including the type and stage of the cancer, the location of the tumour, and your overall health. One or more of the following therapies may be suggested to treat the cancer or help relieve symptoms.

Surgery

Surgery is the most common treatment for stomach cancer. It is sometimes performed with the intent to cure the cancer. However, in some advanced cases, surgery may be palliative—performed primarily to relieve symptoms rather than to cure the disease.

Surgical techniques for stomach cancer include:

  • Endoscopic Mucosal Resection: A thin tube (endoscope) with surgical instruments is inserted down the throat and into the stomach, allowing surgeons to remove certain early-stage, non-invasive stomach cancers.
  • Gastrectomy: The goal of a gastrectomy is to completely remove the cancer and any affected nearby lymph nodes while preserving as much stomach function as possible. Types include:
    • - Partial (Wedge) Gastrectomy
    • - Subtotal (Distal) Gastrectomy
    • - Total Gastrectomy
    • - Robotic Gastrectomy
  • Endoluminal Stent Placement: If a tumour is blocking the stomach but cannot be completely removed, a thin, expandable tube (stent) may be placed between the oesophagus and the small intestine or stomach to keep the passageway open.

Surgery is often combined with chemotherapy and radiation. Where all three are necessary, SSCHRC's standard approach often involves giving chemotherapy and radiation before surgery (neoadjuvant chemoradiation therapy). This helps shrink the tumour and kill cancer cells before the operation, which is often better tolerated and more successful.

Chemotherapy

Chemotherapy uses drugs to kill rapidly dividing cells, including cancer cells. At SSCHRC, chemotherapy for stomach cancer is often administered before surgery to shrink the tumour. It may also be given after surgery to destroy any remaining cancer cells that were not visible during the operation. For more advanced stomach cancer, especially if it has spread, chemotherapy may be used, often in combination with other therapies.

Chemotherapy methods include:

  • • Intravenous (IV) Chemotherapy
  • • Intraperitoneal (IP) Chemotherapy
  • • Hyperthermic Intraperitoneal Chemotherapy (HIPEC) - Also known as 'hot chemotherapy'

Radiation Therapy

Radiation therapy uses precisely focused, high-energy beams to destroy cancer cells. We utilise the most precise methods of radiation therapy to target the stomach cancer while protecting surrounding healthy organs. These methods include:

  • • Intensity-Modulated Radiation Therapy (IMRT): Treatment is tailored to the specific shape of the stomach tumour, ensuring surrounding organs are avoided.
  • • Stereotactic Body Radiation Therapy (SBRT): Very high doses of radiation are targeted at the tumour using multiple beams. SBRT is typically used in cases where the stomach cancer has spread to other areas.

Immunotherapy and Targeted Therapies

Immunotherapy

Immunotherapy harnesses the patient's own immune system to fight the cancer. For stomach cancer, patients may receive a checkpoint inhibitor, a type of immunotherapy that prevents the immune system from prematurely shutting down before the cancer is completely eliminated.

Targeted Therapy

Targeted therapy works by stopping or slowing the growth and spread of cancer at a cellular level. Cancer cells rely on specific molecules (often proteins) to survive, multiply, and spread. Targeted therapies are specifically designed to interfere with these molecules or the cancer-causing genes that produce them.

Genetic/Molecular Profiling

This type of testing classifies cancerous tumours based on their unique genetic makeup. The results help your doctor identify the most suitable immunotherapies, targeted therapies, or clinical trials for that specific cancer.