Colorectal Cancer

Understanding Colorectal Cancers Patient Information

Colorectal Cancer: An Overview

  • Colorectal cancer is a cancer that starts in the rectum or colon, which is the large intestine. Both of these organs are in the lower portion of your digestive system. The colon is also known as the large intestine, and the rectum is at the end of the colon.
  • The colon and rectum, which together form the large bowel, perform vital functions in the last phases of digestion.
  • Digestion first begins in the mouth where food is chewed into smaller pieces and swallowed. The food travels down the esophagus to the stomach where it is further broken down by gastric juices and sent to the small intestine.
  • The small intestine continues to break down the content  in addition to absorbing most of the nutrients, including carbohydrates, proteins and vitamins.
  • Once the contents have passed through the small intestine, the material
    has become mostly liquid and is moved into the colon, which measures about 5 ½ feet long.
  • The main function of the colon is to absorb water and dehydrate the leftover material, forming semi-solid matter, or stool. The colonmoves the stool into the approximately 6-inch long rectum, which acts as a holding chamber, until it is ready to be expelled through the anus.

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

Unavoidable Factors

Some factors that increase your risk of getting colorectal cancer are unavoidable. Getting older is one of them. Your chances of developing the cancer increase after you reach the age of 50. Some other unavoidable risk factors are:

  • a prior history of colon polyps
  • a prior history of bowel diseases
  • a family history of colorectal cancer
  • having a genetic syndrome, such as familial adenomatous polyposis (FAP)
  • being of Eastern European Jewish or African-American descent
Avoidable Factors

Some risk factors for colorectal cancer are:

  • being overweight or obese
  • smoking
  • a heavy use of alcohol
  • having type 2 diabetes
  • having a sedentary lifestyle
  • consuming a diet high in processed foods or red meats

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

  • constipation
  • diarrhea
  • changes in stool color
  • changes in stool shape, such as narrowed stool
  • blood in the stool
  • bleeding from the rectum
  • unexplained weakness
  • passing excessive gas
  • fatigue
  • unintended weight loss
  • abdominal cramps
  • abdominal pain

When to see a doctor:

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

Researchers don’t know what causes colorectal cancer yet. However, they 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 should. This leads to cell accumulation.

Precancerous Growths

Abnormal cells accumulate in the lining of the colon, forming polyps, which are small, benign growths. Removing these growths through surgery is a common prevention method. Untreated polyps can become cancerous.

Gene Mutations

Sometimes, colorectal cancer occurs in family members. This is due to a gene mutation that passes from parent to child. These mutations don’t guarantee that you’ll develop colorectal cancer, but they do increase your chances.

Early diagnosis of colorectal cancer gives you the best chance of curing your colorectal cancer. Your doctor will start by getting information about your medical and family history. They’ll also perform a physical exam. 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 can 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. A colonoscopy also allows your doctor to remove tissue from abnormal areas so they can send them to a laboratory for analysis.

X-Ray

Your doctor may order an X-ray using a radioactive liquid called barium. Your doctor will insert this liquid 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

CT scans provide your doctor with a detailed image of your colon. In the case of colorectal cancer, another name for a CT scan is a virtual colonoscopy.

There are five main stages of colorectal cancer. The higher the number, the more advanced the cancer.
Stage 0: The cancer is confined to the innermost layer of the colon or rectum. It has not yet invaded the bowel wall.

Stage I: The cancer has penetrated several layers of the colon or rectum wall.

Stage II: The cancer has penetrated the entire wall of the colon or rectum and may extend into nearby tissue(s).

Stage III: The cancer has spread to the lymph nodes.

Stage IV:  The cancer has spread to distant organs, usually the liver or lungs. Cancerous tumours found in these organs are called metastases.

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.

  • In the earliest stages of colorectal cancer, it might be possible for your surgeon to remove cancerous polyps through surgery.
  • During surgery, if the polyp hasn’t attached to the wall of the bowels, you’ll likely have an excellent outlook.
  • If your cancer has spread into your bowel walls, however, your surgeon may need to remove a portion of the colon or rectum, 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, they may perform a colostomy.
  • This involves creating an opening in the abdominal wall for the removal of waste. A colostomy is usually temporary.
  • High doses of radiation from a machine are directed to the area of the tumour from outside the body.
  • Radiation is more frequently used to treat rectal cancer.
  • It may be used before surgery to shrink the tumour, making it easier to remove, or after surgery to kill any remaining cancer cells.
  • Chemotherapy involves the distribution of cancer-killing chemicals throughout a patient’s body via a vein, or in a pill form by mouth, to destroy fast-growing cancer cells that may be lingering after surgery.
  • Chemotherapy can also be used to shrink a rectal tumour before surgery, and treat advanced (Stage IV) disease.

Targeted therapies are newer intravenous medications used in advanced disease that target specific biological processes involved in cancer growth. These drugs are different from chemotherapy drugs which kill any fastgrowing cells in the body, including healthy cells.

PartsOfColonNoTitle-SmIntestineLabel-72 low res
coloncancer