Colorectal (Colon) Cancer

Written by Carmella Wint and Jennifer Nelson | Published on July 18, 2012
Medically Reviewed by Brenda B. Spriggs, MD, MPH, FACP

Overview

Colorectal cancer is a cancer that originates in the rectum or colon. Both of these organs are located at the lower portion of your digestive system. The colon is at the end of the large intestine and the rectum is at the end of the colon. According to the American Cancer Society, an estimated one in 20 people will develop colorectal cancer during their lifetime with over 100,000 new cases each year. (ACS)

The Stages of Colorectal Cancer

Doctors use staging as a guideline to figure out how far your cancer has progressed. It’s important for your doctor to know what stage your cancer is so that your doctor can develop the best treatment plan for you. The stages of colorectal cancer start with a Roman numeral I, which is the earliest stage, and go up to IV, the most advanced stage. The stages of colorectal cancer are:

  • cancer has penetrated the lining of the colon or rectum but has not gone beyond the organ walls
  • cancer has spread to the walls of the colon or rectum but hasn’t affected the lymph nodes yet
  • cancer has moved to the lymph nodes but not other parts of the body yet
  • cancer has spread to other organs of the body

What Causes Colorectal Cancer?

As with most cancers, a cause for colorectal cancer hasn’t been discovered yet. However, scientists do know that colorectal cancer develops when healthy cells become abnormal. The abnormal cells divide and multiply faster than they should and don’t die when they’re supposed to, leading to cell accumulation.

Precancerous Growths

In the case of colorectal cancer, abnormal cells accumulate in the lining of the colon forming polyps. Removing these growths through surgery is a common prevention method. Polyps, if left untreated, can become cancerous.

Gene Mutations

In cases where colorectal cancer occurs in family members, a gene mutation passes from parent to child through heredity. While these mutations don’t guarantee that you’ll develop colorectal cancer, they do increase your chances of getting the cancer.

Am I at Risk?

There are some factors that may increase your risk of developing colorectal cancer.

Unavoidable Factors

There are some unavoidable factors that are commonly believed to increase your risk of getting colorectal cancer. Getting older is one of them. The chances of developing the cancer rise after you reach the age of 50. In fact, nine out of 10 people with colorectal cancer are over the age of 50. Some other unavoidable risk factors are:

  • prior history of colon polyps
  • prior history of bowel diseases
  • family history of colorectal cancer
  • genetic syndromes like familial adenomatous polyposis (FAP) an inherited disorder characterized by cancers in the colon, rectum or large intestine, or hereditary non-polyposis colorectal cancer (HNPCC), a rare inherited form of the cancer.

Being of Eastern European Jewish or African American descent has also been shown to increase your risk of colorectal cancer.

Avoidable Factors

Some risk factors for colorectal cancer are:

  • obesity or overweight smoking
  • alcohol excess
  • type 2 diabetes
  • lack of exercise
  • consuming diets high in processed foods or red meats

What are the Signs of Colorectal Cancer?

Colorectal cancer may not present any symptoms, especially in the early stages. But if you do experience symptoms, they may include:

  • changes in bowel movements including constipation, diarrhea, and differences in stool color
  • blood in stool or bleeding from the rectum
  • weakness
  • fatigue
  • unintended weight loss
  • abdominal cramps or pain

If you notice any of these symptoms make an appointment with your doctor to discuss a colon cancer screening.

Diagnosis of Colorectal Cancer

Early diagnosis of colorectal cancer gives you the best chance of having your colorectal cancer cured. Your doctor will start by getting information about your medical and family history. A physical exam is usually performed. The doctor may press on your abdomen or perform a rectal exam to determine the presence of lumps or polyps.

Blood Testing

Your doctor may run some blood tests to get a better idea of what’s causing your symptoms. Though there is no blood test that specifically checks for colorectal cancer, liver function and complete blood count tests are commonly used to rule out other diseases and disorders.

Colonoscopy

A colonoscopy involves the use of a long tube attached to a camera to examine your colon. This procedure allows your doctor to see inside your colon and rectum and note anything unusual. Colonoscopy also lets your doctor remove tissue from abnormal areas so they can be sent to a laboratory for analysis.

X-ray

Your doctor may order an X-ray using a radioactive liquid called barium. This liquid is inserted into the bowels through the use of an enema. Once in place, it coats the lining of the colon and provides an outline so an X-ray can be taken.

CT Scan

Computerized tomography (CT) scans are used to provide your doctor with a detailed image of your colon. In the case of colorectal cancer, CT scans are often referred to as virtual colonoscopies.

Treatment of Colorectal Cancer

Treatment of colorectal cancer depends on a variety of factors. For example, the state of your overall health and the stage of your colorectal cancer will help your doctor create an effective treatment plan.

Surgery

In the earliest stages of colorectal cancer, it might be possible for your doctor to remove cancerous polyps through surgery. During surgery, if it’s found that the polyp hasn’t attached to the wall of the bowels, you’ll likely have an excellent prognosis.

If your cancer has spread into your bowel walls, however, a portion of the colon or rectum may need to be removed along with any neighboring lymph nodes. If at all possible, your surgeon will reattach the remaining healthy portion of the colon to the rectum. If this isn’t possible, a colostomy may be performed. This involves creating an opening in the abdominal wall that’s used for the removal of waste and is usually temporary.

Chemotherapy

Chemotherapy involves the use of drugs that kill cancerous cells. In the case of colorectal cancer, chemotherapy is most commonly used after surgery to destroy any remaining cancerous cells. Chemotherapy is also used to control the growth of your tumor and for symptom relief in late stage cancer.

Radiation

Radiation uses a powerful beam of energy, similar to that used in X-rays, to target and destroy cancerous cells before and after surgery. Radiation is commonly used in combination with chemotherapy.

Medication

In Septembert of 2012, the Food and Drug Administration (FDA) approved the drug regorafenib (Stivarga) to treat patients with colorectal cancer that did not respond to either types of treatment and has spread to other parts of the body. This drug works by blocking enzymes that promote the growth of cancer cells. 

Long-Term Outlook for Colorectal Cancer

When caught early, colorectal cancer is treatable, and, often, curable. With early detection, most people live at least another five years after diagnosis. If the cancer doesn’t return in that time you’re considered cured, especially if you are in the first three stages of the disease. The recovery rate for Stage IV cancer isn’t as optimistic, but it has been cured in rare cases.

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