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Colon cancer is fairly common, with a rate of about one in 15 people being affected. It is a life threatening condition that affects the large intestine. However, if diagnosed early, it is highly curable.
The colon, which is essentially a long tube with different components—cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum and anus—makes up the last five feet of the intestines. After nutrients are digested and absorbed in the small intestine, fibers and undigested food ultimately reach the colon where water and electrolytes are removed. What is left is turned into waste, known as stools. Stools are then stationed in the last part of the colon, the sigmoid and the rectum, until they are excreted.
The body is made up of billions of small cells. Normal cells in the body grow and die in a controlled fashion. Sometimes cells divide and grow uncontrollably, resulting in an abnormal growth called a tumor. If the tumor does not invade nearby tissues, it is called a benign tumor or a non-cancerous growth. Benign tumors are almost never life threatening. Cancers, such as colon cancer, usually start as an overgrowth of normal cells, called a polyp. Cells in the polyp may continue to grow unhindered and, if left unchecked, can become cancerous. Therefore, the earlier the polyps are discovered and removed, the better the chances of preventing or curing the cancer.
If a tumor does invade and destroy nearby tissues or organs, it is called a malignant tumor or cancer, which can be life threatening. Cancerous cells may spread to different parts of the body through blood vessels and lymph channels. This distant spread advances the cancer and makes the cure very difficult.
COMMON SYMPTOMS OF COLON CANCER
- A change in bowel habit such as new onset constipation or diarrhea
- Feeling of incomplete bowel evacuation
- Blood in the stool
- Change in stool caliber, or diameter
OTHER COMMON SYMPTOMS OF COLON CANCER
- Frequent gas pains, cramping or bloating
- Weight loss with no reason
- Feeling tired all the time
- Nausea or vomiting
Most often these symptoms are not due to cancer, but anyone with these complaints should see a doctor and be treated if necessary.
- Lifetime risk of colorectal cancer is roughly equal in men and women.
- Age is a risk factor in that colorectal cancer is most common after age 50, but it can strike at younger ages and the risk of developing colorectal cancer increases with age. African Americans are diagnosed with colorectal cancer at a younger age than other ethnic groups and African Americans with colorectal cancer have decreased survival rates compared with other ethnic groups.
- Family history of colorectal cancer or colorectal polyps and personal history of colorectal polyps increase the risk in close relatives. The vast majority of new colorectal cancers, however, are diagnosed in persons with no family history.
- Certain genetic alterations can increase the risk of colorectal cancer.
- Hereditary non-polyposis colon cancer (HNPCC) is the most common of inherited (genetic) colorectal cancers and accounts for two percent of all colorectal cancers. Most people with the HNPCC gene develop colon cancer and the average age at diagnosis in this high risk group is 44.
- Familial adenomatous polyposis (FAP) is a rare, inherited disorder in which hundreds of polyps form in the colon and the rectum. It is caused by a change in a specific gene called APC. Unless FAP is treated, it usually leads to colorectal cancer by age 39. Luckily, FAP accounts for less than one percent of all colorectal cancers.
- A person who has already had colorectal cancer is at risk for development of colorectal cancer a second time. Also, women with a history of cancer of the ovary, uterus or breast are at a somewhat higher risk of developing colorectal cancer.
- A person who has had an inflammatory bowel disease of the colon (such as ulcerative colitis or Crohn’s disease) is at increased risk of developing colorectal cancer.
- Studies suggest that diets high in fat (especially animal fat) and low in calcium, folate and fiber may increase the risk of colorectal cancer.
- A person who smokes cigarettes may be at increased risk of developing polyps and colorectal cancer.
- Obesity and lack of exercise have been linked to higher rates colorectal cancer.
The best way to treat or cure colon cancer is by finding it before it causes any symptoms.
Colorectal cancer is a common cancer in both men and women in the United States. In 2013, about 143,000 people in the United States were estimated to have been diagnosed with colorectal cancer and 50,830 would have died from it. Colorectal cancer is the number two cancer killer in the United States, yet it is one of the most preventable types of cancer. Colorectal cancers are often curable when detected early and, most important, are eminently preventable by removing the precancerous polyps.
WHAT ARE THE SCREENING OPTIONS?
Talk to your doctor about which screening tests are right for you. The 2009 ACG guideline for colorectal cancer screening divides screening options into cancer prevention tests and cancer detection tests. Cancer prevention tests are preferred over detection tests.
- Preferred Colorectal Cancer Prevention Test: Colonoscopy every 10 years is the preferred colorectal cancer prevention test because it allows physicians to look directly at the entire colon and to identify suspicious growths. In addition, it is the only test that allows a biopsy or removal of a polyp at the very same time it is first identified. For normal risk individuals, the American College of Gastroenterology recommends colonoscopy beginning at age 50, and age 45 for African Americans. However, recommendations for how often colonoscopy should be performed vary for different subsets of high risk individuals, and they should consult with their physician.
- Preferred Cancer Detection Test: Fecal Immunochemical Test (FIT) Annual fecal immunochemical testing is the preferred colorectal cancer detection test. FIT is a relatively new test that detects hidden blood in the stool. If results are positive, a colonoscopy is performed.
DIAGNOSIS OF COLON CANCER
Patients with colon cancer symptoms are evaluated often through history and physical examination followed by tests. The investigations are often comprised of blood tests (to rule out anemia, iron deficiency, etc.), colonoscopy and imaging studies such as CT scans of the abdomen. The intent is to diagnose and stage colon cancer in order to offer the best treatment approach.
TREATMENT OF COLON CANCER
Treatment of colon cancer usually involves surgical resection of the cancer with removal of the surrounding lymph nodes. Depth of penetration of the cancer in the colon wall and the spread to lymph nodes and distant organs dictates the treatment choices. If the cancer is confined to the inner layers of the colon, no further treatment is necessary beyond surgery. On the other hand, if there is invasion of the cancer outside the walls of the colon, the addition of chemotherapy becomes necessary.
Long-term results from a large multicenter study of colonoscopy, funded by the National Cancer Institute, for patients at higher-than-average risk of colorectal cancerconfirm that removing precancerous adenomas (polyps) can not only reduce the risk of colorectal cancer but also reduce the number of deaths from the disease by more than half, which is why it is strongly urged that those at risk for colorectal cancer see a gastroenterologist.
Don’t let embarrassment stop you from scheduling a colonoscopy. This test could indeed be life-saving, and once it’s all said and done, you’ll be glad you did it. Find a center near you to schedule an appointment.
by S Murthy Badiga, MD, FACG