Apr 29, 2022

What is Bowel Cancer? A Deeper Look at Bowel Cancer

Bowel cancer, also known as colorectal cancer, is a type of cancer that develops from the inner lining of the bowel and is usually preceded by growths called polyps, which may become invasive cancer if undetected. Depending on where the cancer begins, bowel cancer may be called colon or rectal cancer.

About 90 percent of bowel cancers are adenocarcinomas, which start in the glandular tissues lining the bowel. Other less common types of cancer can also affect the bowel, including lymphomas and neuroendocrine tumors.



Large intestine (also known as colon/ bowel)

stages-of-colonrectal-cancerStaging criteria for colorectal cancer polyps



Symptoms and signs

Colorectal cancer polyps don’t always cause symptoms, especially at first. Anyone may start developing a polyp without even knowing it. That is why it is imperative to get regular screenings for colorectal cancer, especially if the patient has a family history of cancer or is at risk of getting it.


Symptoms of colorectal cancer may include:

  • Change in bowel movement; diarrhea, constipation or the feeling of incomplete emptying
  • Change in the appearance and consistency of bowel movements, such as thin bowel stools
  • Blood in, or on your stool
  • Constant abdominal pain, aches, bloating or cramping
  • Anal or rectal pain
  • A lump in the anus or rectum
  • Unexplained significant drop in weight
  • Feeling tired and fatigued for no reason
  • Developing anemia symptoms; pale complexion, weakness and breathlessness
  • Bloody urine, or a sudden change in the color of urine; dark, rusty or brown


Causes and risk factors

Increased age is a risk factor for developing colorectal cancer. However, other than age, there are significant causes and risk factors that increase the chances of getting colorectal cancer significantly. These include:

  • Inherited genetic risk and family history
  • Inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis
  • Constant consumption of red meat, especially processed meats
  • Having a high-fat and low-fiber diet
  • High alcohol consumption
  • A history of polyps
  • Being a heavy smoker
  • Being overweight or obese
  • Previously been diagnosed with bowel cancer
  • A genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (Lynch syndrome)



When diagnosed at its earliest stage, more than 9 in 10 (90%) people with colorectal cancer are known to survive for five, or more years, compared to the 1 in 10 (10%) people when the disease is diagnosed at its latest stage.

A number of tests are used to diagnose colorectal cancer. Initially, doctors start with a physical examination to feel for any abdominal swelling. The doctor will also perform a digital rectal examination to check for any lumps or swelling in the rectum or anus.

Other tests that the doctor might recommend are:

  • Blood tests
  • Immunochemical fecal occult blood test (iFOBT)
  • Fecal immunochemical test (FIT)
  • Colonoscopy (examines the entire length of the colon)

  • Flexible sigmoidoscopy (examines only the lower third of the colon)
  • MRI scan
  • CT scan
  • PET scan


Colonoscopy screening vs. Flexible sigmoidoscopy


Colorectal awareness video by King Hamad University Hospital, Bahrain [English subtitles included] 


Treatment options

Despite similarities, outcomes and treatment can vary depending on the stage of the disease and level of invasion and spread.

Despite similarities, outcomes and treatment can vary depending on the stage of the disease and level of invasion and spread.

  • Treatment for early colorectal cancer

- Surgery – The main treatment for early colorectal cancer is surgery. The most common surgery for cancer that begins in the colon is a colectomy. The type of colectomy performed will depend on whether all, or part of the colon needs to be removed.

- Radiation therapy (radiotherapy) – This kind of treatment is often used before surgery for locally advanced rectal cancer, and may be used in combination with chemotherapy to reduce the number and size of cancer cells.

- Adjuvant treatment – Chemotherapy may be recommended after surgery for rectal or colon cancer. This aims to reduce the risk of the cancer returning.

- Palliative care – In some cases of colorectal cancer, the medical team may recommend palliative care. Palliative care aims to improve the patient’s quality of life by alleviating symptoms of cancer, without aiming to cure it. As well as slowing the spread of colorectal cancer, palliative treatment can relieve pain and help manage other symptoms. Treatment may include radiotherapy, chemotherapy or other drug therapies.


  • Treatment for advanced colorectal cancer

- Systemic treatment – This treatment uses drugs that move through the bloodstream to reach cancer cells throughout the body. Systemic treatment can include chemotherapy and targeted therapies.

- Surgery – The patient may be offered surgery to remove small secondary cancers if the cancer has spread to other areas of the body.


What can I do to reduce the risk factors?

Generally, the most effective way to reduce the risk of colorectal cancer is to get screened for colorectal cancer routinely, beginning at the age of 45.

Almost all colorectal cancers begin as precancerous polyps, abnormal growths, in the colon or rectum. These polyps can be found in the colon for years before an invasive cancer develops. They may not cause any symptoms, especially in its first stage. Therefore, regular colon cancer screenings are encouraged as they can find precancerous polyps so they can be removed before they turn into cancer. By doing this, colorectal cancer is prevented, and it can find colorectal cancer early, when treatment works best.

It also goes without saying that a healthy and balanced diet and life style will significantly reduce the risk of getting colorectal cancer. Medical experts often recommend a diet low in animal fats and high in fruits, vegetables, and whole grains to reduce the risk of other chronic diseases, such as coronary artery disease and diabetes. This diet may also reduce the risk of colorectal cancer.

Some studies also suggest that an increase in physical activity, keeping a healthy weight, limiting alcohol consumption, and avoiding tobacco, also helps in preventing colorectal cancer.


Screening for colorectal cancer

Early detection saves lives. It is recommended to make the decision of getting a colorectal cancer screening between the ages of 45 and 75. The decision to get screened between the ages of 76 and 85 should be made on an individual basis.

People whom are at an increased risk of developing colorectal cancer should talk to their doctors about when to begin screening, which test is right for them, and how often to get tested. As stated above, there are several screening tests that can be done to determine whether if a patient has colorectal cancer or not, and the severity of it if so.

To know what tests are right for you, it is preferable to ask your doctors the following questions:

  • Do I need to get a screening test for colorectal cancer?
  • What screening test(s) do you recommend for me? Why?
  • How do I prepare? Do I need to change my diet or my usual medication before taking the test?
  • What’s involved in the test? Will it be uncomfortable or painful?
  • Is there any risk involved?
  • When and from whom will I get the results?
  • If I’m having a colonoscopy, or a sigmoidoscopy, will I need someone with me?


When to see a doctor

If you notice any of the above symptoms constantly presenting for no specific reason, make an appointment with your physician.

Talk to your doctor and ask them about colorectal cancer screenings and the questions mentioned above. Depending on the patient’s medical history and risk factors, the doctor might recommend more frequent, or earlier screening.


 This articles’ sources


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