STOMACH CANCER

Types of Stomach Cancer

Stomach cancer can be classified based on the type of cells involved and the location within the stomach:

1. Adenocarcinoma:

   • The most common type, accounting for about 90-95% of all stomach cancers.
   • Originates in the glandular cells of the stomach lining that produce mucus and digestive juices.

2. Lymphoma:

   • Cancer that originates in the immune system cells found in the stomach lining. This type is relatively rare.

3. Gastrointestinal Stromal Tumor (GIST):

   • A rare type of stomach cancer that starts in the interstitial cells of Cajal in the stomach wall, which are part of the autonomic nervous system.

4. Carcinoid Tumor:

   • Develops from hormone-producing cells in the stomach. These tumors are often less aggressive than other types of stomach cancer.

5. Signet Ring Cell Carcinoma:

   • A subtype of adenocarcinoma known for its aggressive behavior and poor prognosis. The cancer cells resemble signet rings under a microscope.

Risk Factors

• Helicobacter pylori (H. pylori) Infection: A common bacterial infection that can cause chronic inflammation and ulcers, leading to an increased risk of stomach cancer.
• Diet: Diets high in salty, smoked, or pickled foods, as well as a low intake of fruits and vegetables, are linked to a higher risk.
• Smoking: Smokers have a higher risk of developing stomach cancer, particularly in the upper part of the stomach.
• Family History: A family history of stomach cancer or certain genetic conditions like hereditary diffuse gastric cancer increases risk.
• Age and Gender: Stomach cancer is more common in older adults, typically over 50, and is more prevalent in men.
• Obesity: Excess body weight is linked to an increased risk, especially for cancers in the upper part of the stomach near the esophagus.
• Previous Stomach Surgery: People who have had surgery to remove part of the stomach for benign conditions may have a higher risk of developing stomach cancer.
• Pernicious Anemia: A condition caused by a deficiency of vitamin B12, leading to a higher risk of stomach cancer.
• Epstein-Barr Virus (EBV) Infection: Linked to a small percentage of stomach cancers.

Symptoms

Early-stage stomach cancer may not cause any noticeable symptoms, but as the cancer progresses, the following symptoms may appear:

• Indigestion or Heartburn: Persistent discomfort, bloating, or pain in the upper abdomen.
• Nausea and Vomiting: Sometimes with blood (hematemesis) or material that looks like coffee grounds.
• Loss of Appetite: Unintentional weight loss and feeling full after eating small amounts of food.
• Difficulty Swallowing (Dysphagia): Particularly if the cancer is near the junction between the stomach and esophagus.
• Fatigue: Due to anemia from chronic bleeding in the stomach lining.
• Blood in Stool: Stools may appear black and tarry (melena) due to bleeding in the stomach.
• Abdominal Pain: Pain, discomfort, or a lump in the upper abdomen, often on the left side.
• Jaundice: Yellowing of the skin and eyes if the cancer spreads to the liver.

Diagnosis

• Physical Examination: The doctor may feel for any lumps in the abdomen or check for signs of jaundice or anemia.
• Endoscopy: A thin, flexible tube with a camera is inserted through the mouth to examine the stomach lining and take biopsies of suspicious areas.
• Barium Swallow (Upper GI Series): X-rays of the stomach taken after the patient swallows a barium solution, which highlights abnormalities.
• CT Scan or MRI: Imaging tests to determine the extent of the cancer and whether it has spread to other organs.
• PET Scan: Helps to detect cancer spread that may not be visible on other imaging tests.
• Endoscopic Ultrasound (EUS): Combines endoscopy with ultrasound to assess the depth of tumor invasion and involvement of nearby lymph nodes.
• Biopsy: Tissue samples taken during endoscopy are examined under a microscope to confirm the diagnosis of stomach cancer.
• Staging Laparoscopy: A minimally invasive surgery to look inside the abdomen to determine the extent of cancer spread.

Treatment

Treatment for stomach cancer depends on the stage of the cancer, the patient’s overall health, and other factors:

• Surgery:

  • Subtotal Gastrectomy: Removal of part of the stomach along with nearby lymph nodes and possibly parts of other organs.
  • Total Gastrectomy: Removal of the entire stomach, with the esophagus connected directly to the small intestine.
  • Endoscopic Resection: For very early-stage cancers, where the tumor is removed through the endoscope.

• Radiation Therapy:

  • Often used in combination with chemotherapy to shrink the tumor before surgery or to kill any remaining cancer cells after surgery.

• Chemotherapy:

  • Can be used before surgery (neoadjuvant chemotherapy) to shrink the tumor, after surgery (adjuvant chemotherapy) to reduce the risk of recurrence, or to treat advanced cancer.

• Targeted Therapy:

  • Drugs that target specific molecules involved in cancer growth, such as HER2-positive tumors, which are treated with drugs like trastuzumab.

• Immunotherapy:

  • Uses the body’s immune system to fight cancer, particularly for advanced or metastatic stomach cancer.

• Palliative Care:

  • Focused on relieving symptoms and improving quality of life for patients with advanced stomach cancer.

Prognosis

The prognosis for stomach cancer depends on the stage at diagnosis. Early-stage stomach cancer, where the cancer is confined to the stomach lining, has a better prognosis and can often be treated successfully with surgery. However, because stomach cancer is often diagnosed at a later stage when symptoms become noticeable, the overall survival rates tend to be lower compared to some other cancers. The five-year survival rate for localized stomach cancer is around 70%, but it decreases significantly if the cancer has spread to distant organs.

Prevention and Early Detection

• Healthy Diet: A diet rich in fruits, vegetables, and whole grains while limiting salty, smoked, and pickled foods.
• Quit Smoking: Reduces the risk of developing stomach cancer and many other types of cancer.
• Treat H. pylori Infections: If you have a chronic H. pylori infection, treatment with antibiotics may reduce your risk of developing stomach cancer.
• Regular Check-ups: Especially important for individuals with risk factors such as a family history of stomach cancer, pernicious anemia, or previous stomach surgery.
• Screening Programs: In countries with a high incidence of stomach cancer, such as Japan and South Korea, screening programs have helped detect stomach cancer early, improving survival rates .