What is bowel cancer? symptoms, causes & prevention

Bowel cancer is the fourth most common type of cancer in the UK. It affects around 42,300 people each year, and 110 people are diagnosed every day. Bowel cancer can spread via the body’s lymphatic system if it isn’t caught in time. Luckily, statistics from Cancer Research UK show that 54% of cases are preventable, and if it’s caught at its earliest stage, almost 9 in 10 people can survive the disease for 5 years or more. Learning to spot the signs and take quick action can make all the difference. This guide will familiarise you with different types of bowel cancer and how to spot the early warning signs. You’ll also find information on prevention, treatment and how to get tested.

What is bowel cancer?

Cancer that affects the large bowel is referred to as ‘bowel cancer’ or ‘colorectal cancer’. It occurs when abnormal cells begin to grow and spread in the healthy tissue. In most cases, it starts as a small clump of benign cells called ‘polyps’. These gradually become cancerous over time as the bowel cancer stages advance.

There are two main types of cancer in the large bowel area:

  1. Colon cancer: abnormal cell growth in any of the four sections of the large bowel (ascending, transverse, descending and sigmoid).
  2. Rectal cancer: this starts in the back passage of your large bowel.

Polyps don’t always have symptoms, and if they do, they’re very subtle. The best way to catch them before they turn cancerous is to book yourself in for regular bowel screenings, especially if you’re over the age of 60.

What are the symptoms of bowel cancer?

Bowel cancer symptoms might not make you feel ill at first, so they can be harder to spot in the early stages. According to the NHS, 90% of people with bowel cancer experience one of the following symptom combinations:

  • Bloody stools without any of the common symptoms of haemorrhoids
  • More frequent bowel movements which are loose and runny
  • Abdominal pain and bloating directly after eating

A common misconception is that constipation is a sign of bowel cancer, however this is unusual. Any change in usual bowel habit is considered a symptom of bowel cancer and will be taken seriously by your GP.

If left untreated, your bowel cancer symptoms can worsen and may cause a partial or complete obstruction of the bowel. If this has happened, you’re likely to notice some of the following symptoms:

  • Vomiting and sickness
  • Swelling in the stomach
  • Unintentional weight loss
  • Abdominal pain after eating

Symptoms can vary depending on which section of the large bowel is affected and the size of the cancer.  If you’ve had symptoms for 3 weeks or more, you should seek medical advice.

What are the causes of bowel cancer?

Experts still don’t know exactly what causes bowel cancer, but they have identified things that can increase your risk of getting it.

  • Age: bowel cancer is most common in people aged 60 and over.
  • Genetics: your risk increases if you have a close relative who’s had bowel cancer.
  • Type 2 diabetes
  • Excessive alcohol consumption
  • Smoking
  • Inactive lifestyle
  • Poor diet: high fat, high calorie and a high amount of red meat

People with Crohn’s disease or ulcerative colitis are also at high risk of developing bowel cancer, especially if they’ve had the condition for 10 years or more.

How to prevent and treat bowel cancer

Although you can’t change some bowel cancer causes (like age), scientists believe that 54% of cases are preventable with simple healthy lifestyle changes.


The first step to bowel cancer prevention is changing your diet. Eating plenty of fibre and staying hydrated can improve your chances of staying well.

When researching how to stop bowel cancer from developing, scientists found strong evidence to suggest that eating large amounts of red meat and processed meat increases risk.

Alcohol consumption has been linked to bowel cancer, so limiting intake to 1 drink a day could help with bowel cancer prevention.

The best foods for bowel cancer prevention include:

  • Whole grains and fibre
  • Drinking plenty of water
  • Taking a daily multivitamin (especially one with folic acid or folate)
  • Non-starchy vegetables (like cucumbers, carrots, spinach and cauliflower)
  • Calcium-rich dairy products
  • Beans and legumes (lentils, peas, black beans)


There’s a link between bowel cancer and obesity, especially in men. Try to limit the time you spend sitting or lying down and swap it for regular exercise or an active hobby. If you’re worried, you can use an NHS BMI calculator to check whether your current weight is healthy. You can also try a diet and nutrition plan to bring your BMI down.

Testing and screening

Bowel cancer detection usually starts with a conversation with your GP about any symptoms you are having and your risk factors. You are likely to be offered an abdominal examination and also a digital rectal examination (DRE) if you have reported blood in the stools. This is a quick, one-minute test to find lumps in your abdomen or rectum.

You can also opt for a faecal immunochemical test (FIT) home testing kit. You’ll be sent a self-collection kit which you can use to collect a stool sample, which will be sent off for analysis. It analyses tiny particles of blood in your stools which could indicate cancer.

If your test results suggest cancer might be the cause of your symptoms, you’ll be referred to the hospital for a quick procedure called a ‘flexible sigmoidoscopy’. A small camera will be inserted up your back passage so your medical professional can analyse the condition of your lower bowel and even take a biopsy if needed.

You may even be referred for a colonoscopy, which is similar to a sigmoidoscope but examines the entire large bowel rather than just your lower bowel. You could also be offered a CT colonography, which involves inflating the bowel with air and using a CT scanner to take images.


Bowel cancer treatment could depend on where the cancer starts in your large bowel and what stage your cancer is.

These are the stages used to measure how severe bowel cancer cases are:

Stage 1: cancer hasn’t spread beyond your bowel lining

Stage 2: cancer may have penetrated the muscle around the bowel

Stage 3: cancer has spread to the lymph nodes

Stage 4: cancer has spread beyond the bowel and into other organs

Bowel cancer has several different treatment options, and you might even be offered more than one. You can also get treatment if the cancer has spread beyond the bowel.

Here are some of the more common bowel cancer treatment types:

  • Surgery: removing the polyps from an otherwise healthy bowel
  • Radiotherapy: delivers a high dose of radiation to the cancerous cells (commonly used to treat rectal cancer).
  • Chemotherapy: a course of drugs that kill cancers at stage 3 and above.
  • Radiochemotherapy: a combination of radiotherapy and chemotherapy designed to shrink the tumour and reduce the risk of the cancer returning.

In most cases, colon cancer is treatable by surgery (mild cases) or chemotherapy (advanced cases). Rectal cancer is treatable using a blend of all 4 methods listed above.

Do you feel ill with bowel cancer?

The early stages of bowel cancer don’t always make you feel ill, which is why the disease is so difficult to detect without a faecal immunochemical test (FIT) or a medical examination. If the cancer has caused a bowel obstruction, you may fall ill with unpleasant symptoms like vomiting, severe abdominal pain and swelling in the abdomen.

What are the symptoms of bowel cancer in a woman?

The majority of bowel cancer symptoms in women are similar to those in men (you can find these listed above). It’s common to mistake bowel cancer symptoms for gynaecological or menstruation issues, like anaemia, abdominal cramping, and fatigue. If you experience symptoms similar to the ones listed in this guide, it’s recommended you seek medical advice as soon as possible to eliminate bowel cancer as a cause.

What foods cause bowel cancer?

Research has shown that red meat and processed meat increase your risk of bowel cancer. High-risk foods include:

  • Beef
  • Pork
  • Lamb
  • Venison
  • Goat
  • Deli meats
  • Pâté
  • Corned beef
  • Sausages
  • Bacon
  • Luncheon meats
  • Hot dogs

Experts recommend cutting your daily intake down to 70g or enjoying these foods as part of a balanced, healthy diet. You can also choose to introduce a meat-free day into your household each week.

Does bowel cancer spread quickly?

Colon and rectal cancers can take years to develop. A polyp can turn cancerous over 5 – 10 years without showing any obvious symptoms. Once diagnosed, treatments like chemotherapy can help slow the spread of advanced cancers. The bowel cancer survival rate has doubled in the last 40 years, and 53% of people survive for 10 or more years after receiving a diagnosis.

In 2016, Bluecrest Wellness successfully identified 67 cases of bowel cancer using the latest “Immunochemical” tests for a more accurate result and a more comfortable testing experience for patients.

You can book your Bowel Cancer Risk (FIT test) quickly and easily online here. To find out more about reducing your risk by making healthy changes to your diet, read the expert insights on our blog.