Cancer is the transformation of normal cells. These transformed cells grow and multiply abnormally. Cancers are dangerous because of their uncontrolled growth and potential for spread. Cancer overwhelms healthy cells, tissues, and organs by taking their oxygen, nutrients, and space.
In colon cancer, these abnormal cells grow and eventually spread through the colon wall to involve the adjacent lymph nodes and organs. Ultimately, they spread (metastasized) to distant organs such as the liver, lungs, brain, and bones.
Most colon cancers are adenocarcinoma tumors that develop from the glands lining the colon's inner wall. These cancers, or malignant tumors, sometimes are referred to as colorectal cancer, reflecting the fact that the rectum, the end portion of the colon, also can be affected. Anatomic differences in the rectum as compared to the rest of the colon require that doctors separately recognize these areas.
Ulcerative colitis (UC) is an acute or chronic inflammation of the membrane that lines the colon (the large intestine or large bowel). The inflammation occurs in the innermost layer of the colon and may result in the formation of sores (ulcers). Ulcerative colitis rarely affects the small intestine except for the lowermost section, called the terminal ileum. The inflammation makes the colon empty frequently causing diarrhea. Ulcers form in places where the inflammation has killed the cells lining the colon. The ulcers bleed and produce pus and mucus.
UC initially causes inflammation in the rectum and may gradually spread to involve the whole colon. If just the rectum is involved, it is referred to as ulcerative proctitis.
Ulcerative colitis is one of the inflammatory bowel diseases (IBD), the other is Crohn's disease. An estimated 1 to 1.3 million people in the United States have inflammatory bowel disease. Ulcerative colitis generally is found in younger people and the diagnosis often is made in people between the ages of 15 and 30. Less frequently, the disease also can occur in people later in life, even past the age of 60. It affects both men and women equally, and there is a familial predisposition to its development. Those of Jewish heritage have a higher incidence of ulcerative colitis.
Some individuals with colon cancer have no symptoms, and if they do have symptoms they often are minimalized and overlooked until the cancer becomes more severe. Cancer screening tests for colon cancer thus are important in individuals 50 years of age and older. Colon and rectum cancer can have many different symptoms and signs. If you have any of these symptoms, seek immediate medical help. You may notice bleeding from your rectum or blood mixed with your stool. It usually, but not always, can be detected through a fecal occult (hidden) blood test, in which samples of stool are submitted to a lab for detection of blood.
People commonly attribute all rectal bleeding to hemorrhoids, thus preventing early diagnosis owing to lack of concern over "bleeding hemorrhoids." New onset of bright red blood in the stool always deserves an evaluation. Blood in the stool may be less evident, and is sometimes invisible, or causes a black or tarry stool.
Rectal bleeding due to colon cancer may not be noticeable or chronic, and may only show up as an iron deficiency anemia, not colon cancer. Colon cancer may be associated with fatigue and pale skin due to the anemia. Changes in bowel movement frequency also is a symptom of colon cancer.
If the tumor in the colon becomes large enough, it may completely or partially block your colon. Symptoms of bowel obstruction include:
Common symptoms of ulcerative colitis include:
Because inflammatory bowel disease may be caused by a defect in the immune response system, other body organs may be involved, including for example:
Most colorectal cancers arise from adenomatous polyps. Such polyps are comprised of excess numbers of both normal and abnormal appearing cells in the glands covering the inner wall of the colon. Over time, these abnormal growths enlarge and ultimately degenerate to become adenocarcinomas.
People with certain genetic abnormalities develop what are known as familial adenomatous polyposis syndromes. Such people have a greater-than-normal risk of colorectal cancer. In these conditions, numerous adenomatous polyps develop in the colon, ultimately leading to colon cancer. There are specific genetic abnormalities found in the two main forms of familial adenomatous polyposis.
Adenomatous polyposis syndromes tend to run in families, which are referred to as familial adenomatous polyposis (FAP). Celecoxib (Celebrex) has been FDA approved for familial adenomatous polyposis. After six months, celecoxib reduced the mean number of rectal and colon polyps by 28% compared to placebo (sugar pill) 5%.
Hereditary nonpolyposis colorectal cancer (HNPCC) is another group of colon cancer syndromes, which also run in families. In these syndromes, colon cancer develops without the precursor polyps. HNPCC syndromes are associated with a genetic abnormality. A test is available to identify this genetic abnormality. People at risk for this type of colon cancer can be identified through genetic screening. Once identified as carriers of the abnormal gene, these people require counseling and regular screening to detect precancerous and cancerous tumors. HNPCC syndromes sometimes are linked to tumors in other parts of the body.
Other risk factors for developing colon cancer include:
The cause of ulcerative colitis is uncertain. Researchers believe that the body's immune system reacts to a virus or bacteria, causing ongoing inflammation in the intestinal wall. Although UC is considered to be a problem with the immune system, some researchers believe that the immune reaction may be the result, not the cause, of ulcerative colitis.
Emotional stress or food sensitivities do not cause ulcerative colitis; however, these factors may trigger symptoms in some people.
Risk factors for inflammatory bowel disease include:
Polyps, if suggestive of being either cancer-related or cancer-specific in appearance and if few in number, maybe removed during colonoscopy (polypectomy). Sometimes only a polyp is found to be cancerous, and removal (polypectomy) of the polyp may be all that is necessary.
Although the primary treatment of colon cancer is to surgically remove part of the colon or all of it (colectomy) in some patients, chemotherapy after surgery can improve the likelihood of being cured if the colon cancer has spread to nearby lymph nodes.
Radiation treatment (radiation therapy) after surgery does not improve cure rates in people with colon cancer, but it is important for people with rectal cancer. Radiation may reduce tumor size if given before surgery. This can improve the chances that the tumor will be removed successfully. Radiation before surgery also appears to reduce the risk of cancer coming back after treatment. Radiation plus chemotherapy before or after surgery for rectal cancer can improve the likelihood that cancer will be cured.
Usually, only a portion of the colon is removed to treat colon cancer. In rare circumstances, such as in longstanding ulcerative colitis or in cases where large numbers of polyps are found, then the entire colon may need to be removed. Most colon cancer surgery will not result in a colostomy (a piece of colon is diverted and opens through a portion of the abdominal wall) being necessary as the bowel having been cleaned out prior to surgery can then safely be reconnected (resection) after a portion is removed. In rectal cancer sometimes, a colostomy is necessary if it is not safe or feasible to reconnect the portions of the rectum and anus that remain after cancer involved area is removed.
Surgery may also be done to relieve symptoms in advanced cancer such as when cancer has caused a bowel obstruction. The usual procedure is a bypass for obstructions that cannot be cured. Rarely, colon cancer, such as with such severe blockage (obstruction), a resection cannot be done.
Treatment for ulcerative colitis depends on the severity of the disease. Most people with ulcerative colitis are treated with medication. If you have significant bleeding, infection, or complications, surgery may be required to remove the diseased colon. Surgery is the only cure for ulcerative colitis.
Ulcerative colitis may affect individuals in different ways, and treatment is adjusted to meet the needs of the specific individual. Emotional and psychological support is also important.
The symptoms of ulcerative colitis come and go. Periods of remission, in which symptoms resolve, may last for months or years before relapsing. You and your healthcare team, together, need to decide whether medications will be continued during remission times. Medications help manage ulcerative colitis, and stopping them will cause a relapse.
Ulcerative colitis is a lifelong illness and cannot be cured. Routine medical check-ups are necessary and scheduled colonoscopies are important to monitor your health and to make sure that you are managing your ulcerative colitis, and that it is not spreading.
Some people with colon cancer have little or no symptoms until the cancer has become more severe. When symptoms of cancer of the colon do occur, they include bleeding from the rectum, anemia, bloody diarrhea, abdominal distension, nausea, vomiting, and constipation.
