Colon Cancer

What is Colon Cancer?

Cancer is a disease characterized by cells that divide and grow without regulation. Cancer cells form a tumor that can interfere with organ function, invade and damage nearby tissues, and spread to other parts of the body. When cancer begins in the large intestine, it is called colon cancer or bowel cancer. Cancer that begins in the rectum is known as rectal cancer. Together, these cancers are called colorectal cancer. Colorectal cancer is the fourth most common type of cancer in adults today.

The causes of colon cancer are not known, but it is clearly not a contagious disease. Some people are at higher risk for developing colorectal cancer. It is found primarily in people over the age of 50. Cigarette smokers are more like to develop colorectal cancer, as are people whose diets are high in fat and low in fiber. Certain diseases such as Crohn’s disease and ulcerative colitis increase a person’s risk for developing colorectal cancer. Polyps on the inner wall of the colon or rectum can also indicate colon cancer risk.

Symptoms of Colon Cancer

The primary symptom of colon cancer and rectal cancer are changes in the bowel’s function. These can include symptoms such as:

• Diarrhea
  
• Constipation
  
• Feeling like the bowel won’t empty completely
  
• Blood in the stool
  
• Narrow stool
  
• Frequent gas pains or cramps
  
• Bloated feeling
  
• Weight loss
  
• Fatigue
  
• Nausea or vomiting

Treatment Options

The type of treatment for colorectal cancer depends largely on where the tumor is located in the colon or rectum and how far the disease has progressed (the cancer stage.) Colon cancer and rectal cancer are usually treated using surgery, radiation therapy, chemotherapy, or biological therapy. Sometimes people receive a combination of these treatments.

Surgery

Colon cancer is usually treated with surgery to remove the affected area, sometimes in combination with chemotherapy. Radiation therapy is sometimes used to relieve pain and other symptoms associated with colon cancer. People with colon cancer rarely need a complete colostomy.

Rectal cancer is also usually treated with surgery. Some patients also receive chemotherapy and/or radiation therapy. In some cases of advanced disease, patients receive biological therapy. About one out of eight patients with rectal cancer will need a permanent colostomy.

Types of surgery include

• Colonoscopy: a “colonoscope” is inserted through the anus to remove small malignant growthsLaparoscopy: a thin, lighted tube called a laparoscope is inserted through small cuts in the abdomen, allowing the surgeon to see inside the body. The tumor and a portion of healthy colon are removed.

• Open surgery: the surgeon makes a large abdominal cut through which to remove the tumor and visually examine the intestine for signs that the cancer has spread.

After removing the cancerous portion of colon or rectum, the surgeon is usually able to reconnect the healthy parts. In cases where reconnection is not possible—for example, when the anal region has to be removed—the surgeon performs a colostomy. A new outlet for body waste, called a stoma, is created in the abdomen wall. The free end of intestine is connected to the stoma. Waste is collected in a bag worn on the outside of the body. Most colostomies are temporary, to allow the colon or rectum to heal from surgery. After healing occurs, the intestines will be reconnected and the stoma closed.

Radiation Therapy

Radiation therapy, like surgery, only affects the body in the targeted area of the colon or rectum. It uses high-energy rays to kill cancer cells. Radiation can be applied externally, using an external machine, or internally, using radioactive material placed directly in or near the tumor. Occasionally, radiation therapy is performed during surgery, called intraoperative radiation therapy.

Chemotherapy

Chemotherapy is a treatment for cancer using anticancer drugs. This is a systemic treatment for cancer, meaning that it affects cells and tissues throughout the body and not just in the cancerous area. Because chemotherapy harms normal cells that divide rapidly as well as cancer cells, it can cause a number of side effects, include hair loss, increased susceptibility to infection, nausea, vomiting, diarrhea, and mouth and lip sores.

Biological Therapy

Biological therapy is sometimes used to treat advanced cases of colorectal cancer. In this therapy, the patient receives a monoclonal antibody, a type of protein that can bind specifically to cancer cells. Biological therapy can cause an allergic reaction, so patients are given medication to prevent side effects such as rash, fever, diarrhea, vomiting, and breathing problems.

Alternative Treatments and Complementary Medicine

Some people with colon or rectal cancer use alternative and complementary treatments to help treat symptoms and speed their recovery. Approaches such as meditation, massage therapy, acupuncture, herbal supplements, vitamins, and special diets can help relieve symptoms. However, some of them can be harmful or interfere with other treatments being used. It is important to discuss any alternative treatments with a doctor before trying anything new. The National Cancer Institute booklet “Thinking About Complementary and Alternative Medicine: A guide for people with cancer” (www.cancer.gov/cancertopics/thinking-about-CAM) provides additional information about the risks and benefits of different non-traditional options for treatment.