Gastric Cancer: causes, genetics, diagnoses, and treatments

GASTRIC CANCER

  • Gastric cancer as a disease in which cells lining the stomach transform into malignant or cancerous cells. Salted, smoke food, and infections are risk factor for breast cancer. Most (about 90% to 95%) cancers of the stomach are adenocarcinomas. The 5-year survival rate is about 29%.
  • It is well established that infection by bacteria called Helicobacter pylori (H.  Pylori) is one of the main causes of gastric cancer.
  • About 26,240 cases of stomach cancer will be diagnosed (16,520 in men and 9,720 in women)
  • About 10,800 people will die from this type of cancer (6,510 men and 4,290 women)

Gastric cancer as a disease in which cells lining the stomach transform into malignant or cancerous cells.  Most cancers arise from the secreting glands of the stomach (mucous, acids, and fluids) and are referred to as adenocarcinomas.  According, to the cells and layers of the stomach, other types of gastric cancer include gastrointestinal carcinoid tumors, gastrointestinal stromal tumor, and lymphomas.

The stomach is the upper part of the digestive system and it functions in the digestion of processing nutrients like carbohydrates, fats, proteins, vitamins, minerals, and water.

The wall of the stomach is made of 3 layers: The inner lining called the mucosa the medial layer which is the muscularis and the outer most layer which is the serosal layer.  Most gastric cancers originate in the covering layer of the stomach which is called the mucosal layer (adenocarcinoma) and from here spreads and penetrate the outer layers.as it grows, as well as spreading into distant sites.  When the tumors arise from the connective structures to support the stomach they are referred to as stromal tumors.  Likewise, when a tumor arises from the white cells (lymphocytes) that are normal residents of the gastric tissue is called lymphomas.
It is well established that infection by bacteria called Helicobacter pylori (H.  Pylori) is one of the main causes of gastric cancer.  This bacterium has the ability to introduce a protein into the normal gastric cells and transform into cancer cells.  It is for the reason that H pylori eradication therapy has been approving for countries with a high incidence of gastric cancer.  Unfortunately, gastric cancer is often diagnosed at an advanced stage because early signs and symptoms are minimal and almost nonexistent.

 

What are the types of gastric cancer?

Adenocarcinoma

Most (about 90% to 95%) cancers of the stomach are adenocarcinomas. A stomach cancer or gastric cancer usually is an adenocarcinoma. These cancers develop from the cells that form the innermost lining of the stomach (the mucosa).

Pathology

Lymphoma

These cancers of the immune system tissue are sometimes found in the wall of the stomach. The treatment and outlook depend on the type of lymphoma. For more detailed information, see LYmphomas

Gastrointestinal stromal tumor (GIST)

These rare tumors start in very early forms of cells in the wall of the stomach called interstitial cells of Cajal. Some of these tumors are non-cancerous (benign); others are cancerous. Although GISTs can be found anywhere in the digestive tract, most are found in the stomach. For more information

Carcinoid tumor

These tumors start in hormone-making cells of the stomach and secrete hormones into the bloodstream.  Making them highly symptomatic, most of these tumors have mild biological behavior and do not spread to other organs.

Other Cancers

Other types of cancer, such as squamous cell carcinoma, mixed cystic carcinomas (a combination of adenocarcinoma and squamous carcinoma) small cell carcinoma, and leiomyosarcoma, can also start in the stomach, but these cancers are very rare.

 

How frequent is stomach cancer?

The American Cancer Society’s estimates for stomach cancer in the United States for 2018 are:

  • About 26,240 cases of stomach cancer will be diagnosed (16,520 in men and 9,720 in women)
  • About 10,800 people will die from this type of cancer (6,510 men and 4,290 women)

Stomach cancer mostly affects older people.  68 is the average age of diagnosis. About 6 of every 10 people diagnosed with stomach cancer each year are 65 or older. The risk that a man develops stomach cancer in their lifetime is about 1 in 95.  For women, the chance is about 1 in 154.


What are the risk factors for developing gastric cancer?

 

  • Age, being older or male.
  • Diet: Salted and smoke food; and a diet low in fruits and vegetables. Eating and properly stored food.
  • Gastric infections such as chronic gastritis and Helicobacter pylori (H. pylori)
  • Pernicious anemia.
  • Certain geographical locations like Japan, Korea and or Colombia South America have a high incidence of gastric cancer.
  • Familial polyposis syndrome or gastric polyps
  • Smoking cigarettes
  • Hereditary: Having a mother, father, sister or brother who is had stomach cancer

 

What are the symptoms of gastric cancer?

Unfortunately, the symptoms of gastric cancer or minimal and almost nonexistent.  If they appear, the most common are:

Indigestion
Stomach discomfort
Heavy and bloated feeling after eating
Nausea
Vomiting
Loss of appetite
Heartburn and gastric reflux
Bloating the stool
Weight loss for no apparent reason
yellowing of the eyes and skin (Jaundice}
Buildup of fluid in the abdomen (ascites)
Difficulties swallowing

How his gastric cancer diagnosis?

When your doctor suspects that you possible have gastric cancer, in addition to a proper physical examination, he could order the following test:

  1. Blood chemistry studies
  2. Complete blood count
  3. Upper endoscopy

4. Endoscopy ultrasound
5. Barium swallow
6. Computed tomography (CT or CAT) scan

7. Magnetic resonance imaging (MRI) scan

8. Positron emission tomography (PET) scan
9. Biopsy

10. Laparoscopy
11. Molecular markers: Measures the amount of HER2 genes, and how much HER2 protein is being made.  If positive, it is referred to as HER-2–positive gastric cancer and potentially may be treated by immunotherapy that targets the HER-2 protein

How is Gastric Cancer Stage?

Staging is the most fundamental step in treating gastric cancer. It serves to assess the extent of the cancer and the prognosis. The lower the stage the better the prognosis and higher survival rates. The higher the stage the worse the prognosis, the lower the survival rates. The earliest stage stomach cancers are called stage 0 (carcinoma in situ), and then range from stages I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more.

 

How is gastric cancer treated?

 For gastric cancer treatment, not a single approach is used, and treatment often depends on the type of cancer, in most cases, it is a multi-modality treatment strategy. Surgical resection is fundamental for curative treatment for gastric cancer (GC), accompanied by adjuvant modalities.  A number of centers and multiple bodies of evidence suggest neoadjuvant and/or peri-operative strategies in locally advanced tumors. Neoadjuvant approaches are particularly attractive given the morbidity associated with surgical management of GC and the substantial risk of omission of adjuvant therapy.  These neoadjuvant therapies include chemotherapy and radiotherapy.

Chemotherapy

 

In those cancers that are HER-2 positive, a targeted immunotherapy ((trastuzumab- Herceptin) can be given to the patient

 

 

How is gastric cancer prevented?

In a very realistic approach, the onset of gastric cancer cannot be prevented but some steps can be taken to reduce the risk:

–Increase consumption of vegetables and fruits
–Food storage should be with a refrigerator as opposed to      salt with smoking
–Exercises should be part of your physical discipline

-decrease tobacco or alcohol consumption
–Infections with H. Pylori are to be treated with antibiotics
–Proper levels of vitamins
–Learn everything about the cancer.  The more knowledgeable you are, the more involve you can be in your care and treatment.

 

The information in this document does not replace a medical consultation. It is for personal guidance use only. We recommend that patients ask their doctors about what tests or types of treatments are needed for their type and stage of the disease.

Sources:

American Cancer Society

The National Cancer Institute

National Comprehensive Cancer Network

American Academy of Gastroenterology

National Institute of Health

MD Anderson Cancer Center

Memorial Sloan Kettering Cancer Center

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