There are many types of cancer but one of the most horrible kinds is stomach cancer also known as gastric cancer. It is the fourth most common cancer in the world with 21,000 new cases in 2010 and 10,570 deaths according to the National Cancer Institute. It is most common in people in their sixties and seventies and is much more commonly found in men than women with approximately 13,000 men diagnosed in 2010 and 8000 women. Once diagnosed, 26% of people will survive the next five years if the cancer has already spread in the process of metastasis as most often the case is and 63% will survive if it is caught before metastasis has occurred. Thankfully, mortality rates are slowly decreasing across the world with developments in medicines and treatments everywhere.
There are five main types of gastric cancer. The most common of the five is gastric adenocarcinoma, which is the kind in 90% to 95% of stomach cancer cases. It occurs in glandular tissues around the stomach. Intestinal Adenocarcinoma is in tissues near the intestines and most common in those over 80 while diffuse adenocarcinoma is more likely to found in younger patients with blood type A. The remaining four types of stomach cancer are all much more rare. Gastrointestinal lymphoma is found in the immune system tissue of the stomach wall. Gastrointestinal leomysarcoma happens in the muscle layer of the stomach and often doesn’t spread to the lymph nodes. On the other hand, Gastrointestinal Stomal Tumors form in tissues that support the digestive organs when intestinal cells of Cajal are present. The last type, gastrointestinal carcinoid tumors, forms in the stomach tissues that produce hormones and this kind rarely metastizes and spread.
Stomach cancer is often unavoidable but there are some things that can encourage cancerous cell growth and some preventative measures that can be taken although not extremely effective. Smoking has been shown to be linked to gastric cancer and because of this, avoiding smoking is one of the preventative measures that can be taken. Lots of salt and not enough fruits and vegetables also increases the risk so it is good to stay away from salty foods and eat lots of fruits and vegetables because vitamin C is known to decrease the risk. A major cause of gastric cancer is the bacteria Helicobacter pylori (H. pylori), which can grow in the stomach and lead to the growth of cancerous cells. These bacteria are able to remain in the stomach often unnoticed. Although it doesn’t always lead to a case of stomach cancer, this is a very important and common risk factor.
The biggest cause of stomach cancer is genetic. Stomach cancer is largely hereditary meaning that it comes from genes passed down from parent to child. The mutations of these gene’s can lead to the uncontrollable growth of cancer cells in the stomach. Specifically, there are three main genes that can cause gastric cancer. CDH1, a gene that produces proteins that allow cells to adhere to each other and form tissues, acts as a tumor suppressor (a gene that checks to make sure that no problems occurred in the cell cycle and cell division). When this gene mutates, it doesn’t do its job of checking for problems, which can lead to continuous production of cancerous cells without being stopped. Another tumor suppressor gene, TP53, can cause gastric cancer for the same reason when it has mutated, is inactive, or is absent from the area. This happens in 80% of stomach cancer patients. The mutation of APC, a third tumor suppressor gene that also acts as a cell signaler, leads to gastric cancer as well. It mutates in only 25% of gastric adenocarcinoma cases but can mutate in as often as 60% of intestinal stomach cancers.
Another thing that can end up leading to cancer is cyclins. A cyclin is a protein that activates enzymes known as kinases. Kinases then tell a cell to continue on in the cell cycle and divide. Cyclin E in particular is sometimes overexpressed by 20% to 30% and this can lead to the constant production of cancerous cells. When this cyclin activates many kinases and they tell the cells to keep on dividing without stopping, then cancerous stomach tumors grow.
Once someone has a stomach cancer tumor growing inside them, there are several different symptoms that can identify it. They include pains and discomfort in the stomach, nausea and vomiting, swallowing difficulties, weight loss, feeling full even after eating a small meal, vomiting blood, and having bloody stool. These symptoms are not definitive however because they can be found as signs of other diseases as well. This means that if such symptoms are identified, the patient should see a doctor before drawing any conclusions.
In order to diagnose someone with stomach cancer, a gastroenterologist may use several methods. First of all he might feel the abdomen for any abnormalities including swollenness of the lymph nodes. He also might perform an endoscopy where a camera is sent through the mouth and numb esophagus to look inside the stomach for any tumors. A biopsy might also be preformed in which the doctor would use an attachment of the endoscope to remove some tissue. This tissue sample could then be examined for cancer cells.
If the gastroenterologist determines that a patient truly does have stomach cancer, the tumor and cancerous cells must be staged. The purpose of this staging is to determine the best treatment for the patient. The stage of a cancerous tumor is based off of several factors, mainly the tumor itself, the lymph nodes around it, and the amount of metastasis that has taken place. A combination of all these factors determines which stage the cancer is in. Diagnosis tests show the state of each of these factors and help doctors stage the cancer.
The most common method of treatment for stomach cancer at an early stage is surgery. This always involves removal of the tumor. A gastrectomy not only removes the tumor but also the entire stomach. Partial or subtotal gastrectomys are also preformed and this is where only part of the stomach is removed. A third type of surgery that can be used to treat stomach cancer is a resection where the specific tumor is removed along with the surrounding tissues. Each of these methods also normally removes the lymph nodes around the tumor. When such surgery is preformed, the doctors always check back to make sure that the entire tumor was removed and no cancerous cells were left in the body.
Another way that gastric cancer can be treated is using radiation. This is when radiation waves are sent into the body to damage and kill cancer cells. This form of treatment involves repeated radiation sessions and doses for months. The kind of radiation used for stomach cancer is known as external radiation in which a machine directs radiation to the cancerous cells and tumor in the body using a ray. This ray is very direct and specifically pointed so as not to effect places uninhabited by cancerous cells. Radiation doesn’t usually kill noncancerous cells although sometimes it can but all efforts are made to direct it only at cancerous tumors. There unfortunately can be side effects to radiation.
A final method of treatment for gastric cancer is chemotherapy. Medicine and drugs are given to the patient to kill the cancer cells as they divide. They do this by interfering with DNA replication, messing up the spindle fibers that pull apart chromosomes, and damaging DNA. This, as with radiation can have an effect on noncancerous cells but, in the same way, rarely does.
As shown, gastric cancer is a horrible form of constantly dividing cells that form tumors and strongly affects tens of thousands of human beings each year. Although there is not yet a cure for this form of cancer, scientists are working hard to protect and save the lives of those with stomach cancer.
• http://www.cancer.gov/cancertopics/wyntk/stomach
• http://www.cancer.net/patient/Cancer+Types/Stomach+Cancer?sectionTitle=Overview
• http://www.cancer.gov/cancertopics/pdq/prevention/gastric/HealthProfessional/page2
• http://www.omnimedicalsearch.com/conditions-diseases/stomach-cancer-types.html
• http://www.cancerquest.org/gastric-cancer-introduction
• http://www.cancerquest.org/cancer-treatment-surgery
• http://www.cancerquest.org/demo/ACS/RT/RadiationTherapy_V2.swf
• http://www.cancerquest.org/chemotherapy-introduction
• http://www.cancer.gov/cancertopics/factsheet/Risk/h-pylori-cancer
• http://www.biology-online.org/articles/cellular_molecular_aspects_gastric/molecular_mechanisms_gastric_carcinogenesis.html
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