Cancer is a dangerous disease that is caused by an uncontrolled group of abnormal cells in the body. Cancerous cells, also known as malignant tumors or neoplasm, begin to divide without stopping and invade surrounding tissues. The body is made up of trillions of cells, which means cancer can start from almost anywhere in the body. Human cells grow and divide to form new cells continuously. When cells grow old or become damaged they die and new cells are formed to take their place. This process is not the same when cancer starts to develop.
As cells become more and more abnormal, old, or damaged instead of dying, they survive and these mutated cells no longer exhibit their original behavior. These new cells have the ability to divide without stopping and can form growths called tumors. There are different types of cancers and their names are typically based on where they originate, for example; thyroid cancer, which originates in the thyroid and skin cancer, which originates in the skin. This particular paper, however, will be a more focused review of stomach cancer, also referred to as gastric cancer.
The stomach is an organ that lies in the left and central section of the abdomen. The stomach produces many digestive juices and acids that mix with food and help in the process of digestion. Cancer in the stomach just like any other type of cancer is not something pleasant. Stomach cancer is a disease in which the stomach cells become cancerous and grow out of control, creating a tumor. Almost all stomach cancers start in a tissue that lines the stomach called the glandular. The tumors these cells create have the ability to spread along or grow directly through the stomach wall, and shed cells into the blood stream or lymphatic system.
Once these cancerous cells break through the stomach they then can move on and spread the cancer to other parts of the body and to different organs, this spread is referred to as metastasis. There are five regions of the stomach cardia, fundus, antrum, pyloric and the pylorus. Doctors refer to these regions when determining where a stomach cancer begins. Cancer can develop in any of these five sections of the stomach, depending on the location of the cancer, the symptoms and outcomes of the disease will vary.
There are also four stages of cancer for doctors and patients to know how far along and how severe their cancer actually is. Stage 0, abnormal cancerous cells are found in the inside lining of the mucosa of the stomach wall. These cells have the chance to become cancer and spread into nearby normal tissue. Stage 1, cancer has formed in the inside lining of the mucosa of the stomach wall. Stage 1 is divided into stages 1A and stage 1B, depending on where the cancer has spread. Stage 1A, cancer may have spread into the submucosa of the stomach wall.
Stage 1B cancer may have spread into the submucosa of the stomach wall and is found in one or two lymph nodes near the tumor; or has spread to the muscle layer of the stomach wall. Stage II is also divided into two stages IIA and IIB, and IIC depending on where the cancer has spread. Stage IIA cancer has spread to the subserosa of the stomach wall; has spread to the muscle layer of the stomach wall and is found in one or two lymph nodes near the tumor; or may have spread to the submucosa of the stomach wall and is found in three to six lymph nodes near the tumor.
Stage IIB cancer has spread to the serosa of the stomach wall; has spread to the subserosa of the stomach wall and is found in one to two lymph nodes near the tumor; or has spread to the muscle layer of the stomach wall and is found in three to six lymph nodes near the tumor. Stage IIC cancer has spread to nearby organs such as the spleen, transverse colon, liver, diaphragm, pancreas, kidney, adrenal gland, or small intestine, and may be found in three or more lymph nodes near the tumor; or the serosa of the stomach wall and is found in seven or more lymph nodes near the tumor. Stage IV, cancer has spread to distant parts of the body.
There are different types of stomach cancer such as adenocarcinomas, lymphoma, squamous cell, gastrointestinal stromal tumors (GIST), and neuroendocrine tumors. Adenocarcinomas is the most common type of stomach cancer, 95% of stomach cancers are diagnosed as adenocarcinoma. It develops within the cells of the innermost lining of the stomach. Adenocarcinoma is a type of cancer that forms inside the stomach glands throughout the body. It can occur in many different places in the body, and is most common in lung cancer, prostate cancer, pancreatic cancer, colorectal cancer, and Esophageal cancer.
Esophageal cancer is a cancer in the stomach that forms in the glandular cells of the esophagus. All stages of adenocarcinoma use the TNM tumor staging system although the stages vary depending on the location. T means tumor is rated on its size and extent, N means nodes denotes the involvement of the lymph nodes, and M means the tumor that was formed by cells have spread or metastasized. Symptoms of adenocarcinoma include anorexia and weight loss, abdominal pain, nausea and vomiting, feeling full after not eating very much, and vomiting of blood or blood in the feces.
The rate of gastric adenocarcinoma has been steadily decreasing over the last three decades. Gastric adenocarcinoma is rare before the age of forty, but the rate increases with age. Lymphoma is a cancer of the immune system that may start anywhere there are lymphatic tissues/lymphatic cells, including the stomach. Normally these cells and tissues help protect our bodies against infection. Lymphoma cells and tissues affected maybe located in the lymph nodes or in lymphoid tissues located in other sites of the body such as the central nervous system, gastrointestinal tract and the skin.
The lymphomas affecting the gastrointestinal tract, the stomach is the most commonly affected site, then the small and large intestines. Symptoms of lymphoma cancer include upper abdominal pain, upset stomach or indigestion, change of bowel habits, nausea and vomiting, loss of appetite, and weight loss. Most cases of gastric lymphoma occur in those who are fifty or above. Males are at a two to three times greater risk for developing gastric lymphoma. Gastrointestinal stromal tumor (GIST) can be cancerous or non cancerous. It is part of the body’s digestive system.
The GI tract is made up of the stomach small intestine and large intestine. Gastrointestinal stromal tumors are not common but they are most common in the stomach (60%) and small intestine (30%). GIST can be found anywhere in or near the GI tract. Signs that one may have gastrointestinal stromal tumors include blood in the stool (material in a bowel movement) or vomit, pain in the abdomen, feeling very tired, trouble or pain when swallowing and feeling full after only a little food is eaten. Current statistics reveal that the total number of GIST cases range from about 4,000 to 5,000 each year in the United States.
Most people who are diagnosed with GIST are older than fifty, but these tumors can occur in people at any age, and they are proven to be slightly more common in men. Neuroendocrine tumors (NETs) like gastrointestinal stromal tumor can either be cancerous or non cancerous. Neuroendocrine tumors grow in hormone producing tissues, usually in the digestive system. The NETs form from a certain type of neuroendocrine cell, a type of cell that is like a nerve cell and a hormone-producing cell. These cells are scattered throughout the chest and the abdomen but are mostly found in the GI tract.
Neuroendocrine tumors are growths that look benign (non cancerous) but can possibly spread to other parts of the body. Neuroendocrine cancers are abnormal growths of neuroendocrine cells that can spread to other parts of the body. NETs are found in other areas such as the liver, gallbladder, bile ducts, kidneys, ovaries or testicles. NETs usually grow slowly and it could take years for symptoms to appear and for the tumor to be diagnosed. NETs that grow fast are more likely to spread to surrounding tissues, and to other parts of the body. Symptoms of NETs depend on where it is in the body.
In the stomach it will cause pain or discomfort in the abdomen area that will come and go, one will feel nauseated and may vomit, and there can also be changes in ones bowel habits. The most common type of neuroendocrine tumor is the carcinoid tumor. An estimated 11,000 to 12,000 people are diagnosed with carcinoid tumor each year in the United States. Carcinoid tumors usually do not cause symptoms in the early stages. Some patients may experience symptoms such as facial flushing, diarrhea, abdominal pain, asthma, rash and dark-colored stools which mean there is intestinal bleeding.
An estimated 8,000 people in the U. S are diagnosed with neuroendocrine tumors that start in the gastrointestinal tract that includes the stomach. When getting diagnosed there are many tests that take place. First the patient’s physical and medical history exam, this exam is their overall healthy and family background. Blood tests are done to look for any signs of cancer in their body. An upper endoscopy test is done. During this test the doctor will put a thin flexible tube with a small camera down the patients throat to look into their stomach.
The upper GI test is another test that will take place; this test the doctor will have their patient drink a chalky liquid with a substance called barium. The substance helps coat the stomach to make the cancerous cells appear more clearly in x-rays. A CAT scan will be given to the patient to reveal more detailed x-rays of inside the stomach. There will also be a biopsy done, during this particular test the doctor takes a small piece of tissue from the patient’s stomach to look under a microscope for signs of cancerous cells.
Once ones cancer has been diagnosed and staged, there is a lot to think about regarding treatment for their cancer. There are five standard treatments that are used, surgery, chemotherapy, radiation therapy, chemoradiation, and targeted therapy. Surgery is a common treatment for all stages of gastric cancer. There are five types of surgeries that could be used, subtotal gastrectomy, and total gastrectomy are two types that are basically the removal of part of the stomach or the whole stomach, nearby lymph nodes, parts of other tissues and organs near the tumor and parts of the esophagus depending.
There is also the endoluminal stent placement, endoluminal laser therapy and gastrojejunostomy surgery that could be used. Chemotherapy is another treatment to treat stomach cancer. This treatment uses drugs to stop the growth of cancer cells by either killing the cells or by stopping them from dividing. Another type of treatment is radiation therapy. Radiation therapy is a cancer treatment that uses high energy x-rays or other types of radiation to kill cancer cells or keep them from growing.
Chemoradiation is a type of therapy that is combined by chemotherapy and radiation therapy to increase the effects of both. Lastly there is targeted therapy. Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells. If doctors find the stomach cancer in early stages when the cancer is still only in the stomach, the five-year survival rate is about 63%. If the doctors find the stomach cancer when it has spread to areas near the stomach or to nearby lymph nodes the five-year survival rate is 28%.