Bowel cancer is the third most common cancer worldwide: in the developed world 1 million cases are diagnosed annually and it causes 600,000 deaths. In the UK, 1 in every 20 people develop it and about half will die from it. Bowel cancer is uncommon in those younger than 50 unless there is a family history of the disease, or another associated cause. It is a common disease but most people do not have it, even with bowel symptoms! It has been said that it is difficult to determine the symptoms of bowel cancer but an experienced doctor can readily recognise symptom patterns that are high-risk and arrange appropriate investigations 
  High-risk symptom patterns are those that are “new,” and “persistent,” as well as satisfying other criteria to do with the frequency and consistency of bowel motions and of rectal bleeding. When considering rectal bleeding, the most important question is whether or not there are associated anal symptoms, i.e. symptoms of piles, (soreness, pain or lumps at the bottom). It is much more important if rectal bleeding is NOT associated with a sore bottom although your doctor should always examine your bottom to be safe.
  The other most important bowel symptom is to do with a change in the bowel motions from a normal habit (even if that is a little irregular) to a pattern of bowel actions that are either looser than normal, or more frequent, or both. If this symptom is associated with bleeding from the bottom, especially in an older person, it is particularly important.

Points to remember:
1.     Important bowel symptoms are those that are NEW and PERSISTENT for more than six weeks.
2.     Rectal bleeding that is NEW, PERSISTENT and NOT associated with symptoms from the bottom is very important, especially when associated with looser or more frequent stools.
3.     A NEW & PERSISTENT change in bowel function to looser or more frequent stools is important in those aged more than 60.

If your doctor thinks you have high-risk symptoms you will be offered an appointment within two weeks. This is a way of getting to see the specialist quickly but if you go with symptoms that are low-risk you may be offered unnecessary tests that may cause discomfort and risk harm. It is best to wait for a period of a few weeks to see if your symptoms will settle. If your bowels return to normal it is most unlikely that you will have a serious problem.

Screening for bowel cancer

Bowel cancer often starts many years before it causes symptoms. When cancer is diagnosed, it is often much later than it could have been discovered. We know that discovering bowel cancer before it causes symptoms improves survival chances and that screening methods will discover cancers at a much earlier stage.

Since 1997, England has introduced a Bowel Cancer Screening programme that invites 60-75 year-olds to complete a test of three consecutive bowel motions for the presence invisible blood; if the test is abnormal, i.e. blood is detected, patients are recommended to have a complete bowel examination, usually a colonoscopy. Colonoscopy is a test used to look at the bowel lining directly, having cleansed the bowel with laxatives.

Summary

Bowel cancer is a beatable disease if it is detected early. If you have symptoms that concern you, see your GP in the first instance, particularly if you have a family history of it. Most people who have bowel cancer have had it for a while before it causes symptoms. It is reasonable for you to wait for a few weeks to see if your symptoms settle; if they don’t, that is the time to visit your doctor. She or he will then send you to a specialist if they think it right to do so.