How Do You Know if You Have Cancer in Your Intestines?

bowel cancer
Signs of cancer in the intestines include unexplained weight loss

Bowel cancer, also known as colorectal cancer, usually affects the large intestine. Signs and symptoms of cancer in the intestines include:

Intestinal tumors can block the flow of food and affect digestion. As these tumors get bigger, the blockages may cause intense pain in the abdomen, nausea and vomiting and typically requires immediate surgery. A bleeding tumor can also lead to anemia, and digested blood may make stools appear black or tarry.

What is bowel cancer?

Bowel cancer develops from the uncontrolled multiplication of the cells that cover the inner lining of the bowel. Often, bowel cancers develop from polyps, which are small and noncancerous tissue growths.This type of cancer can affect people of all ages. 

  • The large intestine is made up of the colon and rectum. When the cells in the body begin to divide and multiply uncontrollably, this develops into cancer.
  • While bowel cancer is more likely to develop in the large bowel, it can occur in the small bowel as well.
  • The small bowel contains the duodenum (the part of the intestine that connects to the stomach) and ileum (the part of the intestine that connects to the large intestine). The middle part of the small bowel, between the duodenum and ileum, is called the jejunum.
  • When cells have become cancerous in the large bowel, the cells may spread to other areas of the body, such as the liver or lungs. This is what occurs in advanced bowel cancer.

What are causes and risk factors of bowel cancer?

Causes and risk factors of bowel cancer may include:

  • Older age: Most people with bowel cancer are over 50 years of age, and the risk increases with age.
  • Polyps: The presence of many multiple polyps in the bowel can lead to bowel cancer.
  • Bowel diseases: People who have an inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis, are at significantly increased risk for bowel cancer, particularly if they have had the condition for more than eight years.
  • Lifestyle factors: Being overweight, having a diet high in red meat or processed meats (such as salami or ham), drinking alcohol and smoking can increase a person’s risk for developing bowel cancer.
  • Family history: Bowel cancers run in families.
  • Other diseases: People who have had bowel cancer once are more likely to develop it again. Some people who have had ovarian or endometrial (uterine) cancer may be at increased risk of getting bowel cancer.
  • Rare genetic disorders: A small number of bowel cancers are associated with an inherited gene.

What are treatment options for bowel cancer?

Treatment options for bowel cancer may include:

  • Radiotherapy: Attacks cancer cells through radiation.
  • Chemotherapy and biological therapy: Attacks cancer cells through medication.
  • Targeted therapies: A newer group of medicines that increases the effectiveness of chemotherapy and prevents cancer from spreading.
  • Surgery: Removes the affected part of the large bowel.
    • This is the most effective way to treat bowel cancer, particularly if the cancer is limited to the bowel.
    • A method that can be used is keyhole surgery (accessing the body through a small incision), which leads to faster recovery, smaller scars and less pain after the procedure.
    • In some cases, depending on the location of the growth, surgery may lead to the need for a stoma, where the bowel opens onto the skin on the front of the abdomen. This may be done through an ileostomy or a colostomy, and it can be permanent or temporary. Doctors should discuss these procedures with the patient before surgery to make sure they are fully aware of the implications.

Bowel cancer is treatable and can be cured, particularly if it is diagnosed early enough. Nine out of ten people with stage I bowel cancer (the least serious form) survive five years or longer after they are diagnosed. However, this survival rate drops significantly the longer a person has the disease before diagnosis. Guidelines generally recommend that cancer screenings begin at 50 years of age.


Colorectal Cancer: Symptoms, Signs, Screening, Stages See Slideshow
National Health Service. Bowel Cancer.