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Bowel health

Bowel Cancer Explained: Symptoms, Diagnosis and Treatment

Bowel cancer, or colorectal cancer as it is also known, is the 4 th most common cancer diagnosed in the UK. 

Of the approximately 42,000 cases diagnosed annually the majority are aged over 50, but rates in younger adults have increased in the last few years.

Understanding the role of the bowel is important, as is an awareness of risks factors for developing colorectal cancer. Knowing when to seek help is vital too; symptoms of bowel cancer can be subtle and early diagnosis is key to survival rates.

Function of the bowel

map of the bowel

The bowel is made up of the small and large intestines and plays a pivotal role in the digestive system. Its primary function involves the absorption of nutrients and water from ingested food, as well as the elimination of waste products from the body. 

The large intestine, specifically, is responsible for further absorption of water and electrolytes, while also facilitating the formation and expulsion of faeces. 

Contributors to poor bowel health

Several factors can contribute to poor bowel health, increasing the risk of developing bowel cancer:

Dietary Habits: 

Rates of bowel cancer are higher in those with a diet high in processed foods and red meat, and low in fibre.

Lifestyle Choices: 

Sedentary lifestyles, obesity, smoking, and excessive alcohol intake have been linked to higher incidences of bowel cancer.

Genetic Predisposition: 

Individuals with a family history of colorectal cancer or certain genetic syndromes, such as familial adenomatous polyposis (FAP) or Lynch syndrome, are at increased risk.


The risk of bowel cancer rises with age, with the majority of cases diagnosed in individuals over 50 years old.

Inflammatory Bowel Diseases (IBD):

Severe cases of Ulcerative Colitis (UC) and Crohn’s Disease can increase the risk of developing colorectal cancer.

Symptoms of bowel cancer

Symptoms of bowel cancer can be subtle and wide ranging, so it’s important to be vigilant. The most common symptoms experienced are:

Change in bowel habit

You may pass faeces more or less often than previously. This may cause bouts of diarrhoea or constipation.


You may notice blood mixed in with your faeces, or your stool being tarry or very dark in colour.

Mucus mixed in with faeces

A feeling of not having completely emptied your bowels

Abdominal Pain

weight loss


It’s worth noting that all of the symptoms above can be caused by a number of different conditions. Experiencing any of these symptoms does not mean you necessarily have bowel cancer, but it might signify the need for a review with your doctor, or further tests.

How is bowel cancer diagnosed?

lady with bowel discomfort

Initial assessment with a doctor will usually involve a number of questions, and then an examination.

The doctor will likely feel your abdomen, and might need to perform a rectal examination with a gloved finger to feel for any palpable tumours.

It can be useful to perform a blood test, particularly for Full Blood Count (FBC), but these will often be normal. A particular stool sample test called Faecal Immunochemical Test (FIT) is often requested.

This identifies microscopic blood in the stool, and whilst a positive result does not confirm bowel cancer, a negative result is very reassuring and usually means no further tests are required.

If a FIT is positive, or there are other specific concerns, your doctor may refer you for further investigations. These might include any of the following:


A colonoscopy is a test in which a thin, flexible telescope (a colonoscope) is inserted into your rectum and colon. This enables the whole of your colon and rectum to be looked at in detail.

Flexible Sigmoidoscopy

Similar to a colonoscopy, but a shorter telescope is inserted only into the rectum and sigmoid colon.

CT colonography

X-rays are used to build up a series of images of your colon and rectum. This test is useful for people who are unable to have a colonoscopy, or don't want to have one. 

However, if anything is seen on the CT scan, it's likely that a colonoscopy will be required as the next step.


A biopsy involves a small sample of tissue being taken from your body. The sample is then examined under the microscope to look for cancerous cells. If you have a colonoscopy or sigmoidoscopy, the clinician can take a biopsy of any abnormal tissue. 

This is done by passing a thin grabbing instrument down a side channel of the colonoscope or sigmoidoscope.

Bowel cancer treatment

Treatment options that may be considered include:

  • Surgery

  • Radiotherapy

  • Chemotherapy

The most appropriate treatment depends on various factors such as the stage of the cancer, and your general health.

Your specialist will be able to advise, based on your own individual situation. They will be able to give the benefits and risks, chances of success, possible side-effects, and other details about the possible treatment options for your type of cancer.


There has been a significant improvement in bowel cancer prognosis in recent years. Without treatment, a cancerous tumour in the bowel is likely to increase in size and spread to other parts of the body.

However, in many cases it grows slowly and can remain confined to the lining of the colon or rectum for a number of months. Chances of a cure are high if you are diagnosed and treated when the cancer is in this early stage.


Bowel cancer is one of more frequently seen cancers worldwide, and can cause significant problems if not diagnosed and treated early. Understanding the function, and knowing how best to maintain bowel health, is vital in reducing your own individual. 

It’s important, too, to have an awareness of the common symptoms of bowel cancer. There is no single symptom diagnostic of the condition, but knowing when to seek medical attention will lessen the risk of symptoms being ignored, and a delay in diagnosis and treatment.

Other conditions related to the bowel

Irritable Bowel Syndrome

lady with Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common condition that affects the digestive system.

Symptoms caused by IBS are stomach cramps, bloating, diarrhoea and constipation. 

These symptoms can come and go over time, and can last for days, weeks or months at a time. It's usually a lifelong problem and it can be frustrating to live with impacting on your everyday life.

Read our dedicated IBS blog here.

Tests to monitor bowel health

At One Day Tests we offer a range of blood tests that include the monitoring of bowel health.

Any blood test that tests for C-reactive protein (CRP) is a good test to monitor bowel health.

CRP is a marker of inflammation that will rise from any cause of inflammation in the body.

When assessing abdominal symptoms, we use CRP to exclude infection and also to exclude a group of diseases known as Inflammatory Bowel Disease which can cause abdominal pain, blood in your motions, and diarrhoea.

These conditions are ‘autoimmune’ diseases that occur when the immune system mistakenly attacks part of the body.

Here are a selection of blood tests we offer that include C-Reactive protein (CRP) as well as checking for a wide range of other body functions, an ideal full body MOT to ensure you are in peak health.

Bowel Cancer and IBS Awareness Month

April is Bowel Cancer Awareness and IBS Awareness Month

Bowel Cancer Awareness Month is an annual opportunity to raise awareness of bowel cancer and raise important funds to support research into the disease and help those suffering with the Cancer.

Irritable Bowel Syndrome (IBS) Awareness Month also falls in April each year and aims to raise vital awareness of IBS and fund life-changing research, and empower sufferers to seek help sooner.

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