Bowel cancer is an abnormal growth of the inner lining of the large bowel. Bowel cancer
or colorectal cancer as it's often called usually starts as a small, harmless and benign
polyp, which slowly grows over a period of years before it turns into cancer. During
this period, and even when the polyp turns into cancer early on, patients do not experience
symptoms. Perhaps the first symptom that patients may notice which often they may ignore is
rectal bleeding or bleeding from the back passage. So, if you develop bleeding, you
mustn't panic, because the commonest cause of bleeding is piles. However, it is important
that you report the bleeding to your doctor. The problem with bowel cancer is that, by
the time patients develop symptoms, the cancer has become well established. So, symptoms
of bowel cancer include an unexplained and persistent change in the way you open your
bowels towards loose stools, an unexplained or persistent abdominal pain or weight loss,
anaemia, or an abdominal swelling. Again, if you develop any of these swellings, any
of these symptoms, it doesn't mean that you've got cancer. As the risk of cancer with these
symptoms is in the order of three to ten, perhaps 15% depending on what symptom and
the combination of symptoms you have. However, the issue here with bowel cancer is about
early diagnosis. So, the earlier you present to your doctor with your symptoms, the earlier
we detect the cancer and the more likely we are able to cure it for you. So therefore,
it is important when you develop these symptoms that you go and see your doctor so that they
can advise you about whether this should be investigated or not.
Bowel cancer is the fourth commonist cancer in the UK. About 41,000 patients develop the
disease each year. It accounts for about 12 percent of all cancers diagnosed. About 1
in 14 men and 1 in 19 women will experience or will develop bowel cancer during their lifetime.
Bowel cancer can spread if not detected and treated early. So, the cancer usually spreads
to the liver or lungs or other abdominal organs usually by sending cancer cells via the bloodstream.
Also, cancer can spread locally by growing outwards outside the bowel and invading the
nearby organs. It can also grow inside the bowel causing narrowing of the bowel lumen
which leads to blockage. Blockage is a situation whereby you stop opening your bowels, you
stop passing flatus, your abdomen becomes distended and painful, and you may vomit.
Unfortunately, 1/4 of patients with bowel cancer present as an emergency, which means
that cancer is usually advanced and the outcome is not as good as when the cancer is detected early.
Again, this is why it is important that when you develop symptoms you must report
them to your doctor as early as possible.
Bowel cancer can be totally prevented, and when we talk about prevention, we talk about
primary or secondary prevention. So, what do we mean by primary prevention? Well, this
is preventing the disease or the cancer before it develops. That is at the polyp stage. In
other words, before the polyp even develops. For primary prevention, we rely on the patient's
lifestyle. For example, leading an active life or exercising regularly has been shown
to reduce the risk of bowel cancer by up to 50%. Similarly, eating food that is low in
fat and rich in fruits and vegetables can also reduce the risk of bowel cancer by up
to 50%. The role of drugs, medicines which we call in the medical world chemo prevention
is really unclear. There are reports that such as using aspirin or certain non-steroidal
anti-inflammatory drugs can reduce polyp formation and therefore reduce cancer, but there are
other studies that have not confirmed this. So therefore, it's very difficult for us to
recommend this as a treatment or as a preventative measure. With regards to secondary prevention,
this is preventing the disease at the polyp stage. That is before the polyp grows and
turns into cancer. The way this is done is by removing the polyp usually during endoscopic
examination, either by a colonoscopy which allows us to look at the whole of the bowel
or a flexible sigmoidoscopy; which is an examination of the lower third of the bowel. And the reason
why sometimes we do flexible sigmoidoscopy is because 70% of polyps and cancers arise
in this part of the bowel. So, it is seen as a reasonable way of preventing the disease.
We are fortunate in the UK that we've got excellent screening programmes which are dedicated
and focused on secondary prevention.
Well, first let's define what screening means. So, screening is the process of detecting
disease that is too early to cause symptoms in healthy unsuspecting individuals who have
no risk factors other than getting on in life. In other words, getting older. There are two
excellent screening programmes in the UK. The first is the faecal occult blood screening
programme which was introduced about 12 or so years ago. This programme relies on testing
stools for blood using the faecal occult blood test. If the test is positive patients are
invited to have a colonoscopy examination. If the test is negative, the test is repeated
every two years. The programme targets patients between the ages of 61 and 75. Those who are
above 75 can opt to take part in the programme by request. So as soon as you turn 61, you
will find a birthday present delivered to your door which is the invitation to take
part in the screening programme. Now, it is important to know that if the test is positive,
it doesn't mean that you have cancer, but you must have the colonoscopy examination
to make sure that there is nothing there. And if the test is negative and you develop
symptoms in the months afterwards, we must not ignore letting your doctor know about
these symptoms. Because sometimes the test can miss cancers. The second screening programme
is called the Bowel Scope screening programme which was introduced a few years ago. So,
the Bowel Scope involves carrying out one of flexible sigmoidoscopy examinations at
the age of 55 which allows visualisation of the lower third of the bowel. If it shows
polyps, then you are invited for a colonoscopy to have the polyp removed and the rest of
the bowel examined. Now, it is important to say that screening saves lives. And it is
absolutely important that you do not ignore the invitation for screening.