Colorectal Cancer

Bowel/colorectal cancer is cancer that begins in your large bowel. It can also be called colon cancer or rectal cancer depending on where the cancer starts. Most bowel cancers occur in the rectum.

Bowel and colorectal cancer usually develop from small growths on your bowel wall that are called polyps. Most polyps are harmless and are called benign. However, some polyps become cancerous over time and are known as malignant polyps.

Cancerous polyps start to grow quickly and in a strange way. They can grow not just on your bowel lining but into the deeper layers of your bowel wall and to your surrounding tissues including your lymph nodes nearby. If bowel/colorectal cancer advances further, it can spread to other parts of your body such as your liver and lungs. In most cases, bowel cancer grows slowly over many years.

Bowel cancer is categorised into stages that tell you where the cancer is and how far it has spread. Staging bowel/colorectal cancer will help your doctor to determine the best treatment.

As with all cancers, the sooner bowel cancer is detected and diagnosed the better your outcome and chance of survival. It is important to see a doctor as soon as possible if you have bowel/colorectal symptoms. Your doctor will recommend bowel/colorectal cancer tests to investigate your symptoms further.

Most people diagnosed with bowel/colorectal cancer are over the age of 60. Bowel cancer screening is offered on the NHS every two years if you are aged between 60 and 74. This age range is due to be extended to include people aged 50 to 59.

There are three main bowel/colorectal cancer symptoms.

• Bleeding from your back passage or blood in your poo - that is persistent and happens for no obvious reason.
• Ongoing change in your bowel habits – typically looser poo or having to poo more often.
• Persistent stomach pain, cramping or bloating – that is always caused by eating. You may lose your appetite or have significant unexplained weight loss.

These symptoms of bowel/colorectal cancer can be easy to miss. You should take them more seriously as you get older and if they persist.

If you have close family members who have had bowel cancer, you might be worried about your own risk of it. In most cases, bowel cancer is not passed down through the family. However, if you have a family history of bowel cancer in a first-degree relative, including your mother, father, brother or sister and they were diagnosed with the condition before the age of 50, you may have an increased lifetime risk of developing it yourself.

You should be aware that the exact cause of bowel cancer is unknown. Research shows several factors, including family history, may make you more likely to develop it. Other factors include being age 60 or over, eating a diet high in red or processed meats and low in fibre, being overweight or obese, having an inactive lifestyle and drinking alcohol and smoking.

If you’ve had another condition such as extensive ulcerative colitis or Crohn's disease in the colon for more than ten years, you have an increased risk of bowel cancer.

The different types of bowel/colorectal cancer depend on the type of cell it starts in.

• Adenocarcinoma – are by far the most common type of bowel/colorectal cancer. Adenocarcinomas start as gland cells in the lining of your bowel wall. The gland cells normally produce a slimy mucus that helps poo pass through your bowel. There are two rare types of adenocarcinoma called mucinous adenocarcinoma and signet ring adenocarcinoma.

Other types of bowel/colorectal cancer are much rarer. They include:

• Carcinoid tumours– a slow-growing tumour in your hormone-producing tissue, usually in your digestive system. They are part of a group of cancers called neuroendocrine tumours (NETs). Carcinoid is treated in a different way from most common bowel cancer types.
• Squamous cell tumours – these are skin cells that together with gland cells form your bowel lining. Squamous cell tumours are treated in the same way as anus cancer
• Lymphomas - develop in a type of white blood cell called lymphocyte cells in your lymphatic system. Lymphocytes help your body fight infections. Lymphomas are treated very differently from other bowel cancers.
• Sarcomas – also known as gastrointestinal stromal tumours (GISTs). Sarcomas are cancer that forms in supporting cells of your body, such as muscle in the lining of your bowel. Most bowel sarcomas are called leiomyosarcomas and started in smooth muscle. Sarcomas are treated differently from adenocarcinomas.
• Melanoma - develops from skin cells called melanocytes. Melanoma is a type of skin cancer. It can begin in your rectum

These symptoms of bowel/colorectal cancer can be easy to miss. You should take them more seriously as you get older and if they persist.

Bowel cancer can be diagnosed using an endoscopy procedure, including a colonoscopy or a flexible sigmoidoscopy. They involve inserting a flexible tube with a camera through your bottom and into your bowel. The camera sends images to a monitor so that your doctor can see inside your large bowel. A colonoscopy looks at your entire large intestine. A sigmoidoscopy only looks at the lower part of your colon but is less invasive.

If your doctor sees any abnormal or suspicious-looking areas, they will remove a biopsy sample of the tissue and send it to the laboratory for examination. During a colonoscopy, most polyps can be completely removed. In a flexible sigmoidoscopy, small polyps can be removed.

Cancer of the bowel may also be diagnosed by using a CT scanner to produce images of your large bowel. This tends to be used if a colonoscopy was unable to show all of your colon or when a colonoscopy is not safe.

If bowel cancer is diagnosed, you can expect further tests to check if cancer has spread from your bowel to any other parts of your body. They may help your doctors to decide on the most effective treatment for you.

Further tests include:

• CT scan - uses X-rays to create detailed, cross-sectional pictures of the inside of your abdomen and chest. It checks if the rest of your bowel is healthy and whether cancer has spread to your liver or lungs.
• MRI scan – uses a powerful magnet and radio waves to create detailed, cross-sectional pictures of your abdomen, rectum and surrounding organs.

Bowel/colorectal cancer treatment will depend on the stage of your bowel cancer, the part of your bowel that is affected, and your health and fitness for treatment.

Typically, surgery is the main treatment for bowel cancer. It can be combined with chemotherapy, radiotherapy or biological treatments.

Bowel cancer can be cured if it is detected in the early stages. However, a cure is not always possible and bowel cancer can come back. More advanced bowel/colorectal cancer is less likely to be cured.

• Surgery– keyhole or laparoscopic colonoscopy removes polyps and early-stage cancers. For more advanced bowel cancer, surgery removes the cancerous portion of your bowel and some nearby tissue. The bowel ends are then re-joined together. If this is not possible or your surgeon wants to give your bowel a chance to heal, a stoma is created to allow waste to leave your body through a colostomy bag. Surgery may be performed using keyhole (laparoscopic) surgery where your surgeon inserts tiny instruments into several small cuts in your tummy, or by open surgery where your surgeon makes one large cut in your tummy.
• Radiotherapy– destroys the cancer cells using radiation. It may be combined with bowel surgery. Radiation is typically used for rectal cancer treatment.
• Chemotherapy– kills cancer cells using special anti-cancer drugs. It is used to remove cancers that have spread to other parts of your body. This may be before surgery to shrink tumours, after surgery to takeaway cancer not removed in surgery, or if it is not possible to carry out the surgery.
• Targeted cancer drugs – medicines that hunt for cancer cells and interfere with the way they grow. They can be used alongside chemotherapy for bowel cancer especially if it has spread to other parts of your body.

Colon cancer treatment

Surgery is most commonly performed first if you have colon cancer. Keyhole surgery is more frequently used than conventional surgery as the results are the same and keyhole surgery offers much faster recovery times.

Sometimes, chemotherapy may be offered as a primary treatment for colon cancer, although this is less common.

Chemotherapy is often recommended as a follow-up treatment after bowel surgery, unless it is very early-stage cancer.

Rectal cancer treatment

You will usually have a short course of radiotherapy and chemotherapy, called chemoradiation, before surgery to treat rectal cancer. The chemoradiation helps shrink cancer and reduces its risk of return to your rectum.