Gastric Cancer

Identify the stomach

The stomach is a J-shaped organ in the upper left abdomen. It is a major part of the digestive system, which get food through a hollow, muscular tube called the oesophagus. Once food reached the stomach, it stores them there and releases small amounts at a time in to the first part of the small intestine called duodenum.

What is stomach cancer?

Stomach cancer is a malignant growth that starts in the wall of your stomach.

Majority gastric cancers are adenocarcinomas (90%). There are other types of gastric cancers including carcinoid tumors, gastrointestinal stromal tumors (GIST), and lymphomas; all which are rare. In this article, only the gastric adenocarcinoma is discussed and referred to as gastric cancer.

Most commonly, a cell within the inner lining of the stomach becomes abnormal. It stops listening to the instruction given to them about control of cell division, cell growth and cell death. These abnormal cells keeps dividing making more and more abnormal cells. These eventually form a tumour / lump that will expand in to the lumen, then breakdown to create a ulcer/wound in the inner wall of the stomach and grow along the wall around the lumen, and towards out side from the stomach wall.

These tumours will have very abnormal and fragile blood vessels which will cause bleeding in to the lumen. These tumours are solid and rigid thus limiting stomach wall expansion when necessary therefore will cause quick fullness when eating and obstruction to food causing vomiting. Also, they have the potential to detach from the primary tumour and enter the blood stream or lymphatic stream to travel to a far-away places such as liver, lungs, pelvis, ovaries, umbilicus and veins to give rise to another secondary tumour making the eradication of the cancer much harder.

Types of gastric adenocarcinoma

Gastric cancer consists of two types, intestinal and diffuse.

Intestinal Gastric Cancer

The intestinal-type is caused by chronic gastritis associated changes in the inner lining of the stomach. This type is more common among elderly men. This type can be further classified in to early gastric cancer( - confined to the inner lining of stomach) and advanced gastric cancer (extending beyond the inner lining of stomach).

Diffused Gastric Cancer

Diffused type grows in-between layers of the stomach wall leaving the inner lining appear normal (linitis plastica). This type is more seen among women and under the age of 50. This type is associated with an unfavorable prognosis because the diagnosis is often delayed.

Familial gastric cancer

Some families have several members under the age of 40 with diffuse type of gastric cancer. If two or more cases of diffuse gastric cancer in first- or second-degree relatives, with at least one diagnosed before the age of 50 years; OR three or more pathologically documented cases of diffuse gastric cancer in first- or second-degree relatives of any age is present, this can be diagnosed (IGCLC Criteria). One third of these families have been found to have a mutation of the CDH1 gene. Affected family members are also at increased risk for breast and colon cancer

What are the symptoms?

Most patients are asymptomatic in early stages. When they have signs and symptoms, the disease is advanced.

Commonest symptoms are: weight, abdominal pain, epigastric fullness, nausea, loss of appetite, dyspepsia, and mild gastric discomfort. Some present only with anaemia. Tumours near the oesophagus may cause swallowing difficulty or giving the feeling of food sticking (dysphagia). Tumours in the end of the stomach may cause vomiting or feel full after eating only small amounts of food.

Unusual presentations may include acute appendicitis, musculoskeletal pain, and the sudden appearance of skin lesions and freckles, accompanied by pruritis, dermatomyositis and gastrointestinal bleeding causing tarry blackish stools.

How gastric cancer diagnosed?

During the examination, the doctor will look for the signs of anaemia or blood loss. Also will check for recent unintended weight loss. The doctor will check your tummy for palpable tumours, liver anomaly, fluid collections or deposits. He will also check for lymph nodes. The doctor will also check inside the rectum to feel for deposits. The doctor may check for many other specific signs if necessary.

Upper gastro intestinal endoscopy (UGIE) / Gastroscopy provides the most specific and sensitive means of diagnosis of gastric cancers. It allows the surgeon to visualise and biopsy (to take small piece from) the mucosa - inner lining of the oesophagus, stomach and duodenum. The piece taken from the tumour or the suspicious are will be examined under a microscope by a histopathologist and determine whether its intact cancer and if so, the type and the severity of the cancer (grading). This will provide the definitive diagnosis.

Staging

Staging simply means to find out how advanced the disease really is. After gastric cancer has been diagnosed, tests are done to find out if cancer cells have spread within the stomach or to other parts of the body. This process is called staging. This helps to determine the appropriate treatment plan. The staging systems considers the depth of tumor invasion (T), lymph node involvement (N), and distant metastatases/deposits.

Several different methods are used in the staging of gastric cancer, including endoscopic ultrasound (EUS), computed tomography (CT), ultrasound scan, endoscopy, staging laparoscopy, PET scan and tumor markers(CEA).

TNM System for Staging Gastric Cancer

Primary tumor (T):

Regional lymph nodes (N):

Distant metastasis (M):

Worse prognoses are associated with advanced TNM stages, tumors of the cardia, shorter duration of symptoms prior to diagnosis, tumor unresectability, and poorly differentiated histology.

How can stomach cancer be treated?

Treatment aimed at removal of the cancer (“cure”):

Surgery: Removal of the cancer and part of or all your stomach (the subtotal gastrectomy and the total gastrectomy) with bowel joined together allowing you to eat and drink normally (reconstruction).

Types of gastrectomy and reconstruction

Chemotherapy: to shrink the cancer and kill off cancer cells.

A combination of chemotherapy and surgery: This may give the best chance of you being free of stomach cancer.

Radiotherapy after surgery: to reduce the risk of the cancer coming back in the same area.

Treatments to improve swallowing without treating the underlying cancer:

How do I know what is the best treatment for me?

It all depends on the stage of the disease assessed during the staging process and the fitness of the patient for the proposed treatment. If the cancer has not spread to distant areas or organ, removing the cancer by surgery gives the best chance of you being free of stomach cancer.

If the cancer has spread outside your stomach and it is no longer possible for you to be cured, surgery and/or other treatments may control the cancer for a long time and improve your quality of life.

Some people who have other medical problems may not be strong enough to have major surgery and so non-surgical treatments would be better.

Once all the information is available, your doctor will discuss the results at a team meeting with the other specialists involved in your care (Multi Disciplinary team).

The team will recommend the best treatment for you. Your doctor will discuss the recommendation with you and give you further written information to help you to decide what to do.