Medical Devices

What Is Colorectal Cancer? What Causes Colorectal Cancer?

Any cancer - a growth, lump, tumor - of the colon and the rectum is a type of colorectal cancer. Colorectal cancer is also known as bowel cancer. The UK National Health Service says colorectal cancer is the most common cancer globally today. However, the World Health Organization says it is the second most common cancer, after lung cancer. A US study found that incidence rates among adults younger than age 50 years are increasing. According to Medilexicon"s medical dictionary, colorectal cancer is "an autosomal dominant predisposition to early-onset colorectal cancer in the absence of adenomatosis. The disease phenotype may be limited to the colorectum (Lynch syndrome I) or coexist with extracolonic tumors such as endometrial or gastric cancer among others (Lynch syndrome II). The genetic basis is in one of several genes responsible for DNA mismatch repair; in over 90% of cases, the mutation is one of two genes: MSH2 and MLH1." Colorectal cancer rates are increasing worldwide, according to this article. A colorectal cancer may be benign or malignant. Benign means the tumor will not spread, while a malignant tumor consists of cells that can spread to other parts of the body and damage them. What is the colon? What is the rectum? The colon and rectum belong to our body"s digestive system - together they are also known as the large bowel. News on Colorectal Cancer For the latest news and research on Colorectal Cancer, and to sign up to newsletters or news alerts, please visit our Colorectal Cancer News Section. The colon reabsorbs large quantities of water and nutrients from undigested food products as they pass along it. The rectum is at the end of the colon and stores feces (stools, waste material) before being expelled from the body. What are the signs and symptoms of colorectal cancer? *Going to the toilet more often. *Diarrhea. *Constipation. *A feeling that the bowel does not empty properly after a bowel movement. *Blood in feces (stools). *Pains in the abdomen. *Bloating in the abdomen. *A feeling of fullness in the abdomen (maybe even after not eating for a while). *Vomiting. *Fatigue (tiredness). Interesting articles What is cancer? What causes cancer? What is anal cancer? What causes anal cancer? What is colon cancer? What causes colon cancer? All about opioids and opioid induced constipation What is constipation? What causes constipation? What is endoscopy? What is an endoscope? What is a CT scan? What is a CAT scan? What is MRI? How does MRI work? What is pain? What causes pain? *Inexplicable weight loss. *A lump in the tummy or a lump in the back passage felt by your doctor. *Unexplained iron deficiency in men, or in women after the menopause. As most of these symptoms may also indicate other possible conditions, it is important that the patient sees a doctor for a proper diagnosis. Anybody who experiences some of these symptoms for four weeks should see their doctor. How do people get Colorectal Cancer? Experts say we are not completely sure why colorectal cancer develops in some people and not in others. However, several risk factors have been identified over the years - a risk factor is something which may increase a person"s chances of developing a disease or condition. The possible risk factors for colorectal factors are: *Being elderly - the older you are the higher the risk is. *A diet that is very high in animal protein. *A diet that is very high in saturated fats. *A diet that is very low in dietary fiber. *A diet that is very high in calories. *A diet that is very high in alcohol consumption. *Women who have had breast, ovary and uterus cancers. *A family history of colorectal cancer. *Patients with ulcerative colitis. *Being overweight/obese. *Smoking. This study found that smoking is significantly associated with an increased risk for colorectal cancer and death. *Being physically inactive. *Presence of polyps in the colon/rectum. Untreated polyps may eventually become cancerous. *Having Crohn"s disease or Irritable Bowel Disease have a higher risk of developing colorectal cancer. This interesting article by Chinese researchers looks at the risk factor of colorectal cancer. A risk factor is just a risk factor - it increases the risk but in no way guarantees that it will happen. Scientists have identified a common genetic variation associated with the risk of colorectal cancer and its functional implications. Most colon cancers develop within polyps (adenoma). These are often found inside the bowel wall. How common is colorectal cancer? According to WHO (World Health Organization) colorectal cancer is the second most common tumor among both men and women (after lung tumors). Approximately 2% of over 50-year-olds will eventually develop colorectal cancer in Western Europe. 40% of people who are diagnosed with colorectal cancer are already at an advanced stage of the cancer. For these patients surgery is probably the most likely option. Colorectal cancer tends to affect men and women equally. However, men tend to develop it at a younger age. Tests and Diagnosis for colorectal cancer Screening can detect polyps before they become cancerous, as well as detecting colon cancer during its early stages when the chances of a cure are much higher. The following are the most common screening and diagnostic procedures for colorectal cancer: *Fecal occult blood test (blood stool test) - this checks a sample of the patient"s stool (feces) for the presence of blood. This can be done at the GP"s (general practitioner"s, primary care physician"s) office. However, most patients are given a kit that explains how to take the sample at home. The patient then returns the sample to the doctor"s office, and it is sent to a laboratory. A blood stool test is not 100% accurate - it might not detect all cancers because not all of them bleed. Even cancers that do bleed often do not do so all the time. Therefore, it is possible that a patient has a negative result, even though he/she has cancer. Even if blood is detected, this may be caused by other illnesses or conditions, such as hemorrhoids. Some foods may suggest blood in the colon, when in fact, none was present. *Stool DNA test - this test analyzes several DNA markers that colon cancers or precancerous polyps cells shed into the stool. Patients may be given a kit with instructions on how to collect a stool sample at home. This has to be brought back to the doctor"s office, and is then sent to a laboratory. This test is much more accurate for detecting colon cancer than polyps. However, it cannot detect all DNA mutations which may indicate that a tumor is present. *Flexible sigmoidoscopy - the doctor uses a sigmoidoscope, a flexible, slender and lighted tube, to examine the patient"s rectum and sigmoid (the sigmoid colon is the last of the colon, before the rectum). The test does not generally take more than a few minutes and is not painful; but might be uncomfortable. There is a small risk of perforation of the colon wall. If the doctor detects a polyps or colon cancer he/she will then carry on a colonoscopy to examine the entire colon and take out any polyps that are present - they will then be examined under a microscope. A sigmoidoscopy will only detect polyps or cancer present at the end third of the colon and the rectum. If there are any in any other parts of the digestive tract it will not detect them. *Barium enema X-ray - Barium is a contrast dye that is placed into the patient"s bowel in an enema form - it shows up on an X-ray. In a double-contrast barium enema air is added as well. The barium fills and coats the lining of the bowel, creating a clear image of the rectum, colon, and occasionally of a small part of the patient"s small intestine. This procedure is often carried out along with a flexible sigmoidoscopy to detect any small polyps the barium enema X-ray may have missed. If the barium enema X-ray detects anything abnormal, the doctor may recommend a colonoscopy. *Colonoscopy - the doctor uses a colonoscope, which is much longer than a sigmoidoscope. A colonoscope is a long, flexible and slender tube which is attached to a video camera and monitor. The doctor can see the whole of the colon and rectum. Any polyps discovered during this exam can be removed there and then - sometimes tissue samples (biopsies) may be taken instead. Taking biopsies does not hurt. Although colonoscopies are painless, some patients are given a mild sedative to calm them down. Prior to the exam the patient may be given a large amount of laxative fluid to clean out the colon (enemas are rarely used). Bleeding and perforation of the colon wall are possible complications, but extremely rare. *CT colonography (virtual colonoscopy) - a CT (computerized tomography) machine is used to take images of the colon. The patient needs to have a cleared colon for this exam to be effective. Even if anything abnormal is detected, the patient will then need conventional colonoscopy. A study found that CT colonography may offer patients at increased risk of colorectal cancer an alternative to colonoscopy that is less-invasive, is better-tolerated and has good diagnostic accuracy. *Ultrasound scan - sound waves are used to help show if the cancer has spread to another part of the body. *Magnetic resonance imaging (MRI) - this gives a three-dimensional image of the bowel and may help the doctor in his/her diagnosis. Staging the cancer The stage of a cancer means the extent of the cancer. As soon as a colon cancer diagnosis has been made the doctor will determine its stage - this helps chose the most appropriate treatment. The stages of colon cancer are: *Stage 0 (Also known as Duke A stage). - the earliest stage. It is still within the mucosa (inner layer) of the colon or rectum - also called carcinoma in situ. *Stage I (Also known as Duke B stage). - it has grown through the inner layer of the colon or rectum,

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