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Bowel Cancer: Everything You Need to Know

Dr Prudence Knight photo

Created: 23 April, 2019

Updated: 29 April, 2019


Bowel cancer is the fourth most common cancer in the UK, affecting nearly 42,000 people in the UK each year according to Bowel Cancer UK. They add that 1 in 15 men, and 1 in 18 women will be diagnosed with bowel cancer during their lifetime.

Though the majority of bowel cancer diagnoses are in people over the age of 50, it can affect anyone of any age. It is a wholly treatable and curable form of cancer if diagnosed early, however, Bowel Cancer UK note that "nearly everyone survives bowel cancer if [it is] diagnosed at the earliest stage", so to mark Bowel Cancer Awareness Month it pays to understand what the earliest signs and symptoms of bowel cancer are, what causes bowel cancer in the first place, and answer many of the most common questions asked about bowel cancer today.

What are the symptoms of bowel cancer?

According to the NHS, 90% of people with bowel cancer experience one of the following combinations of symptoms:

  • Changes in bowel habits. Going more often, with looser stools and, in some cases, stomach pain.
  • Blood in the stool without haemorrhoid symptoms. And so, removing haemorrhoids or piles from the list of plausible explanations for your symptoms.
  • Abdominal pain, discomfort or bloating resulting from eating. A symptom which, in some cases, results in weight loss or eating less food overall.

Constipation is not a symptom of bowel cancer. In fact, constipation is rarely the result of serious bowel conditions, let alone bowel cancer.

What are the early signs of bowel cancer?

Early signs of bowel cancer include the following, according to Macmillan Cancer Support:

  • Blood in or on the stool
  • Bleeding from the anus – no matter whether the blood is bright or dark red
  • Unexplained weight loss, tiredness, breathlessness or dizziness
  • Feeling bloated after eating
  • Abdominal pain or cramps
  • Anaemia

What causes bowel cancer?

Unfortunately there is no clear cause, or series of causes, that results in the development of bowel cancer that we know of at this time – but research in this area is ongoing.

What can I do to reduce my risk of bowel cancer?

According to Public Health England, there are seven main ways of reducing your risk of developing bowel cancer:

  1. Reducing your intake of red and processed meat. Public Health England recommend eating no more than 70g of beef, lamb, pork, goat, sausages, bacon, cured meats and reformed meat products daily.
  2. Increasing your intake of fibre. Aiding digestion and preventing constipation, fibre should form a key part of your diet. Aim for at least 30g of fibre daily, finding it in wholegrain cereals, wholewheat pasta, oats, beats, chickpeas and lentils.
  3. Staying hydrated. NHS recommendations state that we should aim to drink 6-8 glasses of water a day. Low fat milk, sugar-free drinks, tea and coffee. Fruit juice and smoothies provide fluid but also a lot of water and so are best kept as treats.
  4. Maintaining a healthy body weight. 11% of bowel cancer cases are believed to be linked to the patients in question not having healthy body weights. As such, by maintaining a healthy body weight, you reduce your risk of bowel cancer and several other conditions.
  5. Keeping active. Adults between 19 and 64 years of age are advised to do at least 150 minutes of moderate aerobic exercise each week. Staying active helps maintain a healthy body weight, while also improving your mood.
  6. Reducing your intake of alcohol. 6% of bowel cancer cases are linked to alcohol and alcohol alone. Chief Medical Officers recommend not exceeding more than 14 units of alcohol a week, and making sure those units are spread over the week.
  7. Stopping smoking. 7% of bowel cancer cases are linked to tobacco smoking, with the risk of bowel cancer increasing with the number of cigarettes smoked daily. Further, smokers are more likely to develop polyps in the bowel, which can become cancerous.

How long can bowel cancer go undetected?

Symptoms like unexplained weight loss, fatigue, weakness, abdominal cramps or changes in bowel habits could easily be dismissed by individuals.As such, there is no telling how long bowel cancer could go undetected if symptoms such as these are never investigated. It is worth seeing a GP as soon as symptoms are evident to rule out bowel cancer as a possibility.

How long before bowel cancer spreads?

This varies depending on the type of bowel cancer but can take several years, starting in the lining of the colon or rectum In can then spreadinto the walls of the bowel to the lymph nodes, or even to the liver and lungs. When cancer spreads patients may experience other symptoms like fatigue, weight loss and bone pain.. Like many other cancers, therefore, the sooner you respond to the possible risk of bowel cancer, the better.

How do we test for bowel cancer?

The first port of call in the potential diagnosis of bowel cancer is a digital rectal examination, followed by an abdominal examination – both of which are intended to check for lumps. Though these examinations can be uncomfortable, they generally take less than a minute. Your GP will also test your blood for iron deficiency anaemia at this point and is likely to recommend a stool test to look for microscopic amounts of blood.

From here, you will be referred to a hospital for a flexible sigmoidoscopy, or a more extensive examination of the colon with a colonoscopy or a computerised tomography (CT) colonography. The former examines your rectum and some of the large bowel with a sigmoidoscope, a small camera and light on a long, flexible tube that relays images to a monitor in real time. A colonoscopy involves a similar piece of equipment – a colonoscope – which is essentially a longer sigmoidoscope. The CT colonography procedure is slightly different however, inflating the bowel and scanning the lining to check for irregularities.

Topics: Health and Wellbeing, Women's health, Men's health

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