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Colon Cancer

Colon cancer is a common form of cancer that tends to affect adults aged over 50, though it can occur at any age.

What is colon cancer?

Colon cancer begins in your large intestine (your colon).

It tends to start as polyps (small, benign cells) that develop in your colon. Some of these polyps can become cancerous, causing colon cancer.

Colon cancer is referred to as colorectal cancer sometimes – a term that encompasses cancer of the rectum and colon.

What are the symptoms of colon cancer?

Polyps often don’t produce any symptoms and you sometimes might be diagnosed with polyps, or colon cancer, during a test for a different condition.

However, if you do have symptoms of colon cancer, the most common include:

  • Persistent diarrhea or constipation
  • Rectal bleeding / blood in your stool
  • Abdominal cramps, bloating or gas
  • Unexplained weight loss
  • Fatigue
  • Feeling you haven’t fully emptied your bowel

If you have any of these symptoms, you should see your doctor.

What causes colon cancer?

Colon cancer is caused by a combination of genetic and environmental factors.  Cancer in the bowel is thought to progress from polyps over time. Some patients have a strong genetic predisposition to polyps. However, Genetic conditions account for about 5% of all colon cancers, and Lynch syndrome is strongly associated with colon cancer risk. Your doctor will ask you about your family history of bowel cancer as this can also be a risk factor.

Important environmental risk factors include

  • Poor diet – Diet is a major risk factor. “Western diets” that are high in red meat, processed meats, fat and low in fibre
  • Obesity – this is a major risk factor for many types of cancer
  • The gut microbiome – bacteria and microbes in the gut regulate risk
  • Smoking
  • High alcohol intake
  • Medical conditions – inflammatory bowel conditions or acromegaly (a rare growth hormone disorder)
  • Following radiation therapy for other cancers (e.g. prostate cancer)

How is colon cancer diagnosed?

If you have an average risk of developing colon cancer, you’ll be invited to regular screenings to look for polyps and signs of colon cancer from the age of 50. If you have a higher than average risk due to one or more of the above factors, you’ll be invited earlier.

However, don’t wait for a screening if you’re worried: if you’re experiencing symptoms you think might be caused by colon cancer, see your doctor. To help make a diagnosis, your doctor will ask you about your medical history and symptoms, and may refer you for blood tests or a colonoscopy.

How is colon cancer treated?

Treatment options vary individual by individual. Your treatment depends on a range of factors, such as the stage the cancer is at, your own wishes and your health profile.

In most cases, you’ll be recommended surgery. The type of surgery you have will depend on how far the cancer has spread. If you cancer is caught in the early stages, you may be recommended:

  • Endoscopic Polypectomy – polyps are removed during a colonoscopy. This is known as endoscopic mucosal resection or endoscopic submucosal dissection. It is only suitable for some very early cancers.
  • Trans anal minimally inasive surgery (TAMIS) – early cancers or large polyps in the rectum can be treated with this technique.
  • Laparoscopic surgery – a form of minimally invasive surgery that removes a section of bowel containing the tumour and its associated lymph nodes.
  • Robotic surgery – this is an advanced form of treatment where a surgeon uses a robot to improve the precision of dissection
  • Open surgery – an operation through a cut in the tummy to remove the bowel with the tumour and its associated lymph nodes

Your surgeon will discuss the best treatment for you.

Depending on where the tumour is, you may require a colostomy or ileostomy. This is not always necessary and your surgeon will discuss this with you.

Treatment of colon or rectal cancer may also require the use of chemotherapy, radiation therapy or immunotherapy. Your doctor will discuss your options with you in detail and recommend a treatment option after your case has been discussed in a multi-disciplinary team meeting. Sometimes treatment is required before surgery and sometimes it is given after surgery.

If you’re unsure what treatment you should go for, or the above treatments don’t work for you, our team of expert specialists are here to help.

This content has been checked and approved by

Mr James Kinross  ›

Mr James Kinross is a consultant colorectal surgeon at King Edward VII’s Hospital.

Find your specialist in colon cancer at King Edward VII's Hospital

If you suspect you have colon cancer and you’re seeking an expert opinion, you can find the UK’s leading colorectal specialists here at King Edward VII’s Hospital. Our consultants are hand-picked for you, making it easy to access the best possible care.

Mr Eric Alexandre Chung  ›
Special interests include:
Colorectal cancer (+ 12) more
Mr James Crosbie  ›
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Colorectal surgery (+ 3) more
Mr Amyn Haji  ›
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Colorectal surgery (+ 8) more
Mr Ian Jenkins  ›
Special interests include:
Colorectal surgery (+ 7) more
Mr James Kinross  ›
Special interests include:
Colorectal cancer (+ 8) more
Mr Jonathan McCullough  ›
Special interests include:
Colorectal surgery (+ 7) more
Mr Danilo Miskovic  ›
Special interests include:
General surgery (+ 6) more
Mr Alexander Von Roon  ›
Special interests include:
Colorectal cancer (+ 30) more

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