General Info
Causes of bowel cancer
Cancer occurs when the cells
in a certain area of your body divide and multiply too rapidly.
This produces a lump of tissue known as a tumour. Most cases of bowel cancer first
develop inside clumps of cells on the inner lining of the bowel. These clumps
are known as polyps. However, if you develop polyps, it does not
necessarily mean you will get bowel cancer. Exactly what causes cancer to develop
inside the bowel is still unknown. However, research has shown several factors
may make you more likely to develop it.
There is evidence that bowel cancer can
run in families. Around 20% of people who develop bowel cancer have a close
relative (mother, father, brother or sister) or a second-degree relative
(grandparent, uncle or aunt) who have also had bowel cancer.
It is estimated that if you have one
close relative with a history of bowel cancer, your risk of getting bowel
cancer is doubled. If you have two close relatives with a history of bowel
cancer, your risk increases four-fold.
A large body of evidence suggests a
diet high in red and processed meat can increase your risk of developing bowel
cancer. For this reason, the Department of Health advises people who eat
more than 90 grams (cooked weight) of red and processed meat a day to cut down
to 70 grams.
There is also good evidence that a
diet high in fibre and low in saturated fat could help reduce your bowel
cancer risk. Cancer experts think this is because this type of diet encourages
regular bowel movements.
People who smoke cigarettes are 25%
more likely to develop bowel cancer, other types of cancer and heart
disease than people who do not smoke.
A major study, called the EPIC study,
showed alcohol was associated with bowel cancer risk. Even small amounts
of alcohol can put you at higher risk of getting bowel cancer. The EPIC study
found that for every two units of alcohol a person drinks each day, their risk
of bowel cancer goes up by 8%.
Obesity is linked to an increased
risk of bowel cancer. Obese men are 50% more likely to develop bowel cancer
than people with a healthy weight. Morbidly obese men, who have
a body mass index (BMI) of over 40, are twice as likely to develop bowel
cancer. Obese women have a small increased
risk of developing the condition, and morbidly obese women are 50% more likely
to develop bowel cancer than women with a healthy weight.
People who are physically inactive have
a higher risk of developing bowel cancer. You can help reduce your risk of
bowel and other cancers by being physically active every day. Your risk could
be cut by up to one-fifth if you do an hour of vigorous exercise every day or
two hours of moderate exercise (such as vacuum cleaning or brisk walking).
Some conditions may put you at a higher
risk of developing bowel cancer. People with Crohn’s disease are 2-3 times
more likely to develop bowel cancer. The risk of developing bowel cancer is
much higher in people with ulcerative colitis, and as many as 1 in 20 of these
people will go on to develop it.
There are two rare inherited conditions
that can cause bowel cancer. They are:
- familial adenomatous polyposis (FAP)
- hereditary non-polyposis colorectal cancer
(HNPCC), also known as Lynch syndrome.
FAP affects 1 in 10,000 people. The
condition triggers the growth of non-cancerous polyps inside the bowel.
Although the polyps are non-cancerous, there is a high risk that, over time, at
least one will turn cancerous. Almost all people with FAP will have bowel
cancer by the time they are 50 years of age.
People with FAP have such a high risk
of getting bowel cancer, they are often advised by their doctor to have their
large bowel removed by surgery before they reach the age of 25.
Families affected can find support and advice from the FAP registry at St
Mark’s Hospital, London.
HNPCC is a type of bowel cancer caused
by a mutated gene. An estimated 2-5% of all cases of bowel cancer are
due to HNPCC. Around 90% of men and 70% of women with the HNPCC mutation will
develop bowel cancer by the time they are 70 years of age. As with FAP, removing the bowel as a
precautionary measure is usually recommended in people with HNPCC.
Symptoms
Early bowel cancer may have no
symptoms and some symptoms of later bowel cancer can also occur in
people with less serious medical problems, such as haemorrhoids (piles). You must see your doctor if you notice any of
the symptoms below. The initial symptoms of bowel cancer
include:
As bowel cancer progresses, it can
sometimes cause bleeding inside the bowel. Eventually, this can lead to
your body not having enough red blood cells. This is known as anaemia.
Symptoms of anaemia include:
In some cases, bowel cancer can cause
an obstruction in the bowel. Symptoms of a bowel obstruction include:
You should see your doctor if you have any
of the symptoms above. While the symptoms are unlikely to be the result of
bowel cancer, these types of symptoms always need to be investigated further.
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Diagnosing bowel cancer
When you first see your doctor they
will ask about your symptoms and whether you have a family history of
bowel cancer. They will then carry out a physical
examination known as a digital rectal examination (DRE). A DRE involves
your doctor gently placing their finger into your anus, and then up into your rectum.
A DRE is a useful way of checking
whether there is a noticeable lump inside your rectum. This is found in an
estimated 40-80% of cases of rectal cancer. A DRE is not painful, but some people
may find it a little embarrassing. If your symptoms suggest you may have
bowel cancer, or the diagnosis is uncertain, you will be referred to your local
hospital for further examination.
Early diagnosis of bowel cancer results in more effective treatment and hence longer survival.
Two tests are commonly used to confirm
a diagnosis of bowel cancer:
- A sigmoidoscopy is an examination of your rectum
and some of your large bowel.
- A colonoscopy is an examination of all of your
large bowel.
A sigmoidoscopy uses a device called a
sigmoidoscope, which is a thin, flexible tube attached to a small camera and
light. The sigmoidoscope is inserted into your
rectum and then up into your bowel. The camera relays images to a monitor.
This allows the doctor to check for any abnormal areas within the rectum
or bowel that could be the result of cancer.
A sigmoidoscopy can also be used to
remove small samples of suspected cancerous tissue so they can be tested in the
lab. This is known as a biopsy. A sigmoidoscopy is not usually painful,
but can feel uncomfortable. Most people go home after the examination has been
completed.
A colonoscopy is similar to a
sigmoidoscopy except a longer tube, called a colonoscope, is used to
examine your entire bowel. Your bowel needs to be empty when a
colonoscopy is performed, so you will be given a special diet to eat for a few
days before the examination and a laxative (medication to help empty your
bowel) on the morning of the examination.
You will be given a sedative to help
you relax, after which the doctor will insert the colonoscope into your rectum
and move it along the length of your large bowel. As with a sigmoidoscope, the
colonoscope can be used to obtain a biopsy, as well as relaying images of any
abnormal areas.
Schematic diagram showing how a colonoscopy is performed, and some of the most common pathologies at the different parts of the large bowel.
A colonoscopy usually takes about one
hour to complete, and most people can go home once they have recovered from the
effects of the sedative. After the procedure, you will probably feel drowsy for
a while, so arrange for someone to accompany you home.
If a diagnosis of bowel cancer is
confirmed, further testing is usually carried out for two reasons:
- to check if the cancer has spread from the
bowel to other parts of the body
- to help decide on the most effective treatment
for you.
These tests can include:
- a computerised tomography (CT)
scan or magnetic resonance imaging (MRI) scan to provide a
detailed image of your bowel and other organs
- ultrasound scans, which can be used to look
inside other organs, such as your liver, to see if the cancer has spread
there
- chest X-rays, which can be used to assess the
state of your heart and lungs
- blood tests to detect a special protein, known as a tumour marker, released by the cancerous cells in some cases of bowel cancer.
Once the above examinations and tests
have been completed, it should be possible to determine the stage and grade
of your cancer. Staging refers to how far your cancer has
advanced. Grading relates to how aggressive and likely to spread your
cancer is.
- Stage 1 – the cancer is still
contained within the lining of the bowel or rectum
- Stage 2 – the cancer has spread into
the layer of muscle surrounding the bowel
- Stage 3 – the cancer has spread into
nearby lymph nodes
- Stage 4 – the cancer has spread into
another part of the body, such as the liver.
This is a simplified guide. Stage 2 is
divided into further categories called A and B and stage 3 is divided into A, B
and C.
There are three grades of bowel cancer:
- Grade 1 is a cancer that grows slowly and
has a low chance of spreading beyond the bowel
- Grade 2 is a cancer that grows moderately
and has a medium chance of spreading beyond the bowel
- Grade 3 is a cancer that grows rapidly
and has a high chance of spreading beyond the bowel.
If you are not sure what stage or grade
of cancer you have, ask your doctor.
Treating bowel cancer
People with bowel cancer should be
cared for by a multidisciplinary team (MDT). This is a team of specialists who
work together to provide the best treatment and care. The team often consists of a specialist
cancer surgeon, an oncologist (a radiotherapy and chemotherapy specialist), a
radiologist, pathologist, radiographer and a specialist nurse. Other members
may include a physiotherapist, dietitian and occupational therapist, and you
may have access to clinical psychology support.
When deciding what treatment is best
for you, your doctors will consider:
- the type and size of the cancer
- your general health
- whether the cancer has spread to other parts
of your body
- what grade it is.
There are several treatments for bowel
cancer, including:
- surgery
- chemotherapy
- radiotherapy
- biological therapy.
Surgery is usually the main treatment
for bowel cancer, but in about one in five cases, the cancer is too advanced to
be removed by surgery. If you have surgery, you may also need chemotherapy,
radiotherapy or biological therapy, depending on your particular case.
Your recommended treatment plan will
depend on the stage and location of your bowel cancer. If the cancer is confined to your
rectum, radiotherapy will usually be used to shrink the tumour, then surgery
may be used to remove the tumour. Sometimes, radiotherapy is combined with
chemotherapy, which is known as chemoradiation.
If you have stage 1 bowel cancer, it
should be possible to surgically remove the cancer and no further treatment
will be required. If you have stage 2 or 3 bowel cancer,
surgery may be used to remove the cancer and, in some cases, nearby lymph
nodes. Surgery is usually followed by a course of chemotherapy to stop the
cancer returning.
It is not usually possible to cure
stage 4 (advanced) cancer. However, symptoms can be controlled and the spread
of the cancer can be slowed using a combination of surgery, chemotherapy,
radiotherapy and biological therapy where appropriate.
Surgery - colon cancer
If the cancer is at a very early stage,
it may be possible to remove just a small piece of the lining of the colon
wall. This is known as local excision. If the cancer spread into muscles
surrounding the colon, it will usually be necessary to remove an entire section
of your colon. Removing some of the colon is known as a colectomy. Depending on the location of the
cancer, possible surgical procedures include:
- left-hemi colectomy – where the left
half of your colon is removed
- transverse colectomy – where the
middle section of your colon is removed
- right-hemi colectomy – where the
right half of your colon is removed
- sigmoid colectomy – where the lower
section of your colon is removed.
There are two ways a colectomy can be
performed:
- In an open colectomy, the surgeon makes a
large incision in your abdomen and removes a section of your colon.
- A laparoscopic colectomy is a type of
‘keyhole surgery’, where the surgeon makes a number of small incisions in
your abdomen and uses special instruments guided by a camera to remove a
section of colon.
Both techniques are thought equally
effective in removing cancer and have similar risks of complications.
Laparoscopic colectomies have the advantage of a faster recovery time and less
post-operative pain. Laparoscopic colectomies should now be
available in all hospitals carrying out bowel cancer surgery, although not all
surgeons perform this type of surgery. If you are considering having your bowel
cancer surgery done using keyhole surgery, discuss this with your surgeon.
During surgery, nearby lymph nodes may
also be removed. It is usual to join the ends of the bowel together after bowel
cancer surgery, but very occasionally this is not possible and a stoma is
needed.
Enhanced recovery surgical
programmes should be used for most bowel cancer patients. These
programmes differ from traditional surgery by:
- ensuring patients are in the best possible
physical condition before surgery
- minimising the trauma patients go through
during surgery - for example, minimally invasive surgery when
possible and better pain control
- ensuring patients experience the best possible
rehabilitation after surgery.
Stoma surgery
In some cases, the surgeon may decide
the colon needs to heal before it can be reattached, or that too much of the
colon has been removed to make reattachment possible. In this case, it will be necessary to
find a way of removing waste materials from your body without stools passing
through your anus. This is done using stoma surgery.
Stoma surgery involves the surgeon
making a small hole in your abdomen, which is known as a stoma. There are
two ways that stoma surgery can be carried out.
- An ileostomy is where a stoma is made in
the right-hand side of your abdomen. Your small intestine is separated
from your colon and connected to the stoma, and the rest of the colon is
sealed. You will need to wear a pouch connected to the stoma to collect
waste material.
- A colostomy is where a stoma is made in
your lower abdomen and a section of the colon is removed and connected to
the stoma. As with an ileostomy, you will need to wear a pouch to collect
waste material.
In most cases, the stoma will be
temporary and can be removed once your colon has recovered from the effects of
the surgery. This will usually take at least nine weeks. Specialist stoma
nurses are available to advise on the best site for a stoma, and about the best
sort of pouch to cover the stoma and collect the waste material. Before you have a colectomy, your care
team will tell you whether they think stoma surgery will be necessary and the
likelihood that you will need to have a temporary or permanent ileostomy or
colostomy.
Two common surgical procedures can be
used to treat rectal cancers:
- low anterior resection
- abdominoperineal resection.
Low anterior resection is a procedure used
to treat cases where the cancer is in the upper section of your rectum. The
surgeon will make an incision in your abdomen and remove the upper section of
your rectum, as well as some surrounding tissue to make sure any lymph glands
containing cancer cells are also removed.
They will then attach your colon to
the lowest part of your rectum or upper part of the anal canal. Sometimes, they
turn the end of the colon into an internal pouch to replace the rectum. You
will probably require a temporary stoma to give the join-up time to heal.
Abdominoperineal resection is used to
treat cases where the cancer is in the lowest section of your rectum. In this
case, it will be necessary to remove the whole of your rectum and
surrounding muscles to reduce the risk of the cancer regrowing in the same
area.
This involves removing the anus and its sphincter muscles too, so there
is no option except to have a permanent stoma after the operation. Bowel
cancer surgeons always do their best to avoid giving people permanent stomas
wherever possible.
Bowel cancer operations carry the same
risks as other major operations, including the risks of bleeding, infection,
developing blood clots or heart or breathing problems. One risk is that the join-up
in the bowel may not heal properly and may leak inside your
abdomen. This is usually only a risk in the first few days after the
operation.
Another risk is for patients having
rectal cancer surgery. The nerves controlling passing urine and sexual
function are very close to the rectum, and sometimes an operation to
remove a rectal cancer can damage these nerves. After bowel cancer surgery, the bowel
is shorter than it used to be. This results in some patients needing
to go to the toilet to open their bowels more often than before. This usually
settles down within three to six months of the operation.
Radiotherapy
There are two main ways
that radiotherapy can be used to treat bowel cancer. It can be:
- given before surgery, in cases of rectal
cancer
- used to control symptoms and slow the spread
of cancer, in cases of advanced bowel cancer (called palliative
radiotherapy).
Radiotherapy given before surgery for
rectal cancer can be performed in two ways:
- external radiotherapy, where a machine is used
to beam high-energy waves at your rectum to kill cancerous cells
- internal radiotherapy (also known as
brachytherapy), where a radioactive tube is inserted into your anus and
placed next to the tumour to shrink it.
External radiotherapy is usually given
daily, five days a week, with a break at the weekend. Depending on the size of
your tumour, you may need one to five weeks of treatment. Each
session of radiotherapy is short and will only last for 10-15 minutes. Internal radiotherapy can usually be
performed in one session before surgery is carried out a few weeks later. Palliative radiotherapy is usually
given in short, daily sessions, with a course ranging from 2-3 days to 10 days. Short-term side effects of radiotherapy
include:
- nausea
- fatigue
- diarrhoea
- burning and irritation of the skin around the
rectum and pelvis (this looks and feels like sunburn)
- a frequent need to urinate
- a burning sensation when passing urine.
These side effects should pass once the
course of radiotherapy has finished. Tell your care team if the side effects of
treatment become particularly troublesome. Additional treatments are often
available to help you cope better with the side effects.
Long-term side effects of radiotherapy
include:
- a more frequent need to pass urine or stools
- blood in your urine and stools
- infertility
- impotence in men.
If you want to have children, it
may be possible to store a sample of your sperm or eggs before treatment begins
so they can be used in fertility treatments in the future.
Chemotherapy
There are three ways chemotherapy
can be used to treat bowel cancer. It can be:
- given before surgery for rectal cancer in
combination with radiotherapy
- given after surgery to prevent the return of
cancer
- given to slow the spread of advanced bowel
cancer and help control symptoms (palliative chemotherapy).
Chemotherapy for bowel cancer usually
involves taking a combination of medications that kill cancer cells. They can
be given as a tablet (oral chemotherapy), through a drip in your arm
or chest (intravenous chemotherapy), or as a combination of both. Depending on the stage and grade of
your cancer, a single session of intravenous chemotherapy can last from several
hours to several days.
Most people have regular daily sessions
of chemotherapy over the course of one or two weeks before having a break from
treatment for another week. A course of chemotherapy can last up to
six months depending on how well you respond to the treatment. Side effects of chemotherapy include:
- fatigue
- nausea
- vomiting
- diarrhoea
- mouth ulcers
- hair loss
- redness and soreness on the palms of your
hands and the soles of your feet
- a sensation of numbness, tingling or burning
in your hands, feet and neck.
These side effects should gradually
pass once your treatment has finished. It usually takes three to six months for
your hair to grow back. Chemotherapy can also weaken your
immune system, making you more vulnerable to infection. Inform your care team
or doctor as soon as possible if you experience possible signs of an infection,
including:
- a high temperature (fever) of 38ºC (100.4ºF)
or above
- a sudden feeling of being generally unwell.
Medications used in chemotherapy
can cause temporary damage to men's sperm and women's eggs. This
means that for women who become pregnant or for men who father a child, there
is a risk to the unborn baby’s health. Therefore, it
is recommended you use a reliable method of contraception while
having chemotherapy treatment and for a further year after your treatment has
finished.
Chemotherapy is the use of
'anti-cancer' (also known as cytotoxic) drugs to destroy cancer cells in
the body. Chemotherapy is used at different stages of treatment, and can be
used in combination to make other treatments more effective:
- 'Neo-adjuvant' –
to shrink the tumour(s) before surgery in order to get a
better outcome following the operation.
- 'Adjuvant' – to destroy any
microscopic cancer cells that may remain after the cancer is removed by
surgery and reduce the possibility of the cancer returning.
- 'First-line' – chemotherapy that
has been shown, through extensive clinical trials and research, to be the best
option for the type of cancer being treated.
- 'Second-line' –
chemotherapy that has been shown, through extensive clinical trials and
research, to be the best option if the disease has not responded to
first-line chemotherapy or has recurred.
- 'Palliative' – to relieve symptoms and
slow the spread of the cancer, if a cure is not possible.
In order for the chemotherapy to
destroy cancer cells in the body, the drugs must be absorbed into your blood
and carried throughout your body. The chemotherapy drugs can be given in
different ways:
- Oral chemotherapy: If
your chemotherapy drug is available as a tablet you can swallow, this
can be taken at home. You only go to the hospital for routine outpatients'
appointments, which include a blood test. As oral chemotherapies can cause
side-effects it is important to keep a diary of how you are feeling and
possible side-effects to ensure that you are able to identify and report
them to your medical team immediately.
- Intravenous (IV) injection:
The treatment is injected into a vein. There are a wide range of schedules
for chemotherapy which can vary from a small injection over a few minutes,
a short infusion of up to 30 minutes, or longer infusions over
the course of a couple of hours or even a couple of days.
Intravenous chemotherapy can be given
via four different methods:
- Cannula: A small tube inserted into
a vein in the back of your hand, or your arm.
- Central Line: A thin, flexible tube
inserted though the skin of the chest into a vein near the heart. Hickman®
or Groshong® lines are common types and can stay in place for
many months.
- PICC Line: A
thin, flexible tube passed into a vein in the bend or upper part of your
arm and threaded through the vein until the end of the tube lies in a vein
near the heart. PICC lines can stay in place for
many months.
- Portacath: A thin, soft plastic tube
that is put into a vein. It has an opening (port) just under the skin on
your chest or arm.
Chemotherapy can affect your sense of
taste and smell, dull your appetite and make you feel sick. It may also
make your mouth and throat sore or sensitive to hot and cold food and
drink.
Biological Therapy
Biological treatments, including cetuximab,
bevacizumab and panitumumab, are a newer type of medication known as
monoclonal antibodies. Monoclonal antibodies are antibodies that have been
genetically engineered in a laboratory. They target special proteins found on
the surface of cancer cells, known as epidermal growth factor receptors
(EGFR). As EGFRs help the cancer to grow, by targeting these proteins,
biological treatments can help prevent the cancer spreading.
Biological treatments are usually used in combination
with chemotherapy and radiotherapy.
These treatments are not available to everyone
with bowel cancer. The National Institute for Health and Clinical Excellence
(NICE) has determined specific criteria which need to be met before they can
be prescribed. Cetuximab is only available on the NHS when:
Bevacizumab and panitumumab are not available on
the NHS. All these medications are available privately but are very
expensive. The medication is usually given in combination with
chemotherapy.
Source: NHS Choices. |