Colon cancer, also known as colorectal cancer, is a disease characterized by malignant growths in a person's colon, appendix and rectum. Colon cancer is one of the most common forms of cancer and is the second leading cause of cancer-related deaths in the United States. More than 100,000 cases of colon cancer are reported each year, mostly affecting men and women 50 years old or older. The overall risk of developing colon caner is 7 percent and the survival rate depends on the stage of the disease.
Characteristics and Symptoms
The main characteristic of colon cancer is cancerous polyps in a person's large intestine. These polyps usually begin as benign cells that clump together to form adenomatous polyps. Over time these noncancerous cells can become malignant leading to a diagnosis of colon cancer. The polyps begin along the top layer of the colon wall, but over time can penetrate through the colon and into neighboring organs.
Initial symptoms of colon cancer include internal bleeding, weight loss and fatigue. As the cancer progresses and develops, symptoms can include changes in bowel movements, such as constipation or diarrhea, bloody stools, tar-like stools or pain while making a bowel movement.
Diagnosis
Colon cancer is typically diagnosed through a colonoscopy, an endoscopic procedure during which a probe is inserted into a person's rectum. The probe is connected to a monitor allowing the doctor to see the entire length of a person's colon. If polyps are found during the colonoscopy, they can be biopsied and tested to see if they are malignant.
In addition, blood tests can also be used to screen for elevated protein levels, which could indicate the presence of cancerous polyps. X-rays and CAT scans can also be used to detect tumors; however a colonoscopy is typically the preferred method because the polyps can easily be biopsied.
Treatment
The initial treatment is surgically removing the malignant polyps and tumors. In early stages of colon cancer, this is possible by cutting the polyps during the colonoscopy. In more advanced stages of the disease, surgery could include removing the length of a person's colon containing the cancer. In such a case the remaining portions of a person's colon are connected. During surgery the lymph nodes near the colon are also usually removed.
After surgery, chemotherapy or radiation is used in some cases to kill any remaining cancer cells. This often happens when the cancer has penetrated the wall of colon, because chemotherapy or radiation can help prevent the tumors from reoccurring and kill any that spread to other organs.
Chances of Survival
The survival rate for people with colon cancer depends on whether the disease has spread to other organs and how much the cancer has penetrated the wall of the colon. If the disease is confined to the top layer of the colon and there is no sign of metastasis (the spreading of the disease to other organs), the long-term survival rate is usually 80 percent or higher. However in people where the disease has metastasized to other organs, less than 10 percent will survive more than 5 years.
Risk factors
Genetics and diet can lead to increased risks for people to develop colon cancer. If one or both of a person's parents had colon cancer, that person will be about 3 times more likely to develop colon cancer than a person who has no immediate family history of the disease. Also studies have shown that a diet high in fat increases the risk of colon cancer because the breakdown of fat by the body can lead to the production of cancer-causing chemicals. A diet rich in vegetables and high-fiber foods can help the body rid itself of these harmful chemicals.
Prevention
Colon cancer can be prevented by early detection. Doctors recommend that individuals undergo a yearly rectal examination beginning at age 40, and a colonoscopy every 3 to 5 years beginning at age 50. A rectal examination can detect abnormal growths in the colon, while a colonscopy can detect polyps that can be removed before they become cancerous. People with high risk factors will often be encouraged to begin preventative screenings earlier.
Tags: colon cancer, other organs, person colon, colon cancer, survival rate, also used