In this article
Identify the rectum
The rectum joins the colon to the anus. It is about 15cm (6 inches) long.
Its described by dividing in to three parts. upper, middle and lower. The upper third is the section directly after the sigmoid colon. The lower third is where the large bowel joins the anus. The middle third is in between.
The wall of the rectum is made up of 4 layers of tissue.
What is rectal cancer?
Most commonly, a cell within the inner lining of the rectum becomes abnormal. It stops listening to the instruction given to them about control of cell division, cell growth and cell death. These abnormal cells keeps dividing making more and more abnormal cells. These eventually form a tumour / lump that will expand in to the lumen, along the wall around the lumen, and towards out side from the bowel wall.
These tumours will have very abnormal and fragile blood vessels which will cause bleeding in to the lumen. These tumours are solid and rigid thus limiting bowel wall expansion when necessary therefore will cause constipation / obstruction. When they spread outside the rectal wall, they may invade other pelvic organs/structures in the vicinity. Also, they have the potential to detach from the primary tumour and enter the blood stream or lymphatic stream to travel to a far-away places such as liver or lungs to give rise to another secondary tumour making the eradication of the cancer much harder.
What are the symptoms?
The symptoms of rectal cancer may include:
- blood in, or on, your poo (stool) or bleeding from the back passage (rectum) – the blood may be bright red or dark
- a change in your normal bowel habit that happens for no obvious reason and lasts longer than three weeks – for example, diarrhoea or constipation
- unexplained weight loss
- pain in your tummy (abdomen) or back passage
- feeling that you haven’t emptied your bowel properly after you poo
- unexplained tiredness, dizziness or breathlessness
- a lower than normal level of red blood cells (anaemia)
- an itchy bottom, although this is rare.
Sometimes the cancer can cause a blockage (obstruction) in the bowel. You may feel constipated and bloated, vomit, and have tummy pain. These symptoms can be caused by conditions other than rectal cancer, but you should always have them checked by your doctor. If you have symptoms that don’t improve within a few weeks, or if your symptoms get worse, it is important that you are referred to a specialist. They can do tests to find out what the problem is.
How rectal cancer is diagnosed
If you have symptoms, you need to consult a doctor. Its better to consult a specialist such as a gastroenterological surgeon because they have been trained specially in diagnosing and treating rectal cancer. They are the best doctors to properly manage rectal cancer.
Some people's diagnosis is suspected after taking a test such as stools occult blood which is done as a screening test. Some will be diagnosed during a colonoscopy done for some other reason or for screening. Either way, you need to be seen by a specialist. Either way, you need to be seen by a specialist.
Sometimes people are diagnosed with rectal cancer after going to hospital with a problem, such as bowel obstruction. It may cause symptoms such as tummy pain, nausea and vomiting, and constipation. In this scenario, you may straightaway need a specialist consultation.
Digital Rectal Examination (DRE)
During the specialist consultation, the doctor will ask you about your general health and any previous medical problems you have had, and any cancer diagnoses with in the family members. Then you'll be examined and may under go a rectal examination(DRE) which is done by inserting a gloved finger in to your back passage to feel for a cancer. Following this, the doctor will arrange few more diagnostic tests such as CEA and colonoscopy in addition to blood tests to assess general health.
If you are already in bowel obstruction, doctor may attempt to relieve the obstruction either by stenting or surgery prior to staging amd proper treatment.
Carcinoembryonic Antigen CEA
Your blood may be tested for a protein called carcinoembryonic antigen (CEA). Some people with bowel cancer have higher levels of this protein. If your level of CEA is high, your doctors may check it regularly to see how well your treatment is working.
What ever the initial symptom is, you need to undergo a colonoscopy to be definitively diagnosed whether you have rectal cancer. A colonoscopy looks at the inside of the whole length of the large bowel. You can usually have this test as an outpatient. It takes about an hour. During the colonoscopy, it will be possible to visualize the cancer and to take a small tissue sample for further testing. This will conclude the diagnosis. If you cannot undergo the colonoscopy, you have the option of undergoing a CT colonogram (Virtual colonoscopy). However, to obtain a tissue sample, it would be mandatory to have the colonoscopy.
Virtual colonoscopy (CT colonography)
In a virtual colonoscopy, a CT (computerised tomography) scanner takes a series of x-rays, which builds up a three- dimensional picture of your bowel. It is done in the hospital CT department and you can usually have it as an outpatient.
This test may be done instead of a colonoscopy, or it may be done if the colonoscopy didn’t give a clear enough picture.
You may also have an injection of a dye (called a contrast medium). Your radiologist will tell you if you are going to have this.
Just before the scan, your doctor passes a tube into your back passage (rectum) and pumps in some air and gas (carbon dioxide). This expands the bowel and helps to give a clearer picture. You will have two CT scans – one lying on your back and one lying on your front.
Once the diagnosis is confirmed, it is necessary to find out the size and position of the cancer and whether it has spread in order to plan the appropriate treatment. This involves doing some more tests. These are to This is called staging.
Staging Contrast CT scan
This test checks for any signs that the cancer has spread outside the rectum. A Contrast CT scan is done after you were given a drink or while you are getting an injection of a dye (provided that you are not allergic to it), which allows particular areas to be seen more clearly. A CT scan takes a series of x-rays, which build up a three- dimensional picture of the inside of the body. The scan takes 10–30 minutes and is painless. It uses a small amount of radiation, which is very unlikely to harm you and will not harm anyone you come into contact with.
Some people also have a PET/CT scan. This is a combination of a CT scan (see above) and a positron emission tomography (PET) scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body. A PET/CT scan may occasionally be done if more detailed information is needed after a CT scan. It may also be used to plan treatment if there is cancer in the liver or lungs.
MRI (magnetic resonance imaging) scan
If your staging scan reveals a cancer that extends outside the rectum but not grossly invaded in to the other pelvic structures, then the MRI scan will help to determine whether you have a chance of complete local removal of the tumour at the surgery . This test uses magnetism to build up a detailed picture of areas of your body. The scanner is a powerful magnet so you may be asked to complete and sign a checklist that exclude any possibility of having a metal part inside the body to make sure it’s safe for you. If
Endorectal ultrasound scan (ERUS)
This test is an alternative test to the MRI scan. Ultrasound scans use sound waves to build up a picture of body tissues. An endorectal ultrasound scan can show the size and location of a cancer in the rectum and to some degree on the outside of the rectum. This is an operator dependant scan.
This is a combination of a CT scan, and a positron emission tomography (PET) scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body. PET-CT scans give more detailed information about metastatic toumour presence in the other part of the body being scanned.
The stage of a cancer describes its size and whether it has spread. Knowing the stage of the cancer helps doctors decide on the best treatment for you. The most commonly used staging system is the TNM system.
TNM staging system
T – describes how far the tumour has grown into the wall of the bowel, and whether it has grown into nearby tissues or organs.
N – describes whether the cancer has spread to the lymph nodes.
M – describes whether the cancer has spread to another part of the body such as the liver or lungs (secondary or metastatic cancer).
T – Tumour
- Tis means the cancer is at its earliest stage (in situ). It is growing into the mucosa but no further.
- T1 means the tumour is only in the inner layer of the bowel (submucosa).
- T2 means the tumour has grown into the muscle layer of the bowel wall but no further.
- T3 means the tumour has grown into the outer lining of the bowel wall (serosa) but no further.
- T4 means the tumour has grown through the outer layer of the bowel wall (serosa) and through the membrane covering the outside of the bowel wall (peritoneum).
- T4a means it has grown into other nearby structures, such as other parts of the bowel or other organs or body structures.
- T4b means the tumour has caused a hole in the bowel wall (perforation) and cancer cells have spread outside the bowel.
N – Nodes
- N0 means no lymph nodes contain cancer cells.
- N1 means there are cancer cells in up to three nearby lymph nodes.
- N2 means there are cancer cells in four or more nearby lymph nodes.
M – Metastases
- M0 means the cancer has not spread to distant organs.
- M1 means the cancer has spread to distant organs, such as the liver or lungs.
Number staging system
Information from the TNM system can be used to give a number stage from 0 to 4.
- Stage 0 – The cancer is at its earliest stage and is only in the mucosa (Tis N0 M0).
- Stage 1 – The cancer has grown into the submucosa or muscle but has not spread to the lymph nodes or elsewhere (T1 N0 M0 or T2 N0 M0).
- Stage 2 – The cancer has grown through the muscle wall or through the outer layer of the bowel, and may be growing into tissues nearby. The cancer has not spread to the lymph nodes or elsewhere (T3 N0 M0 or T4 N0 M0).
- Stage 3 – The tumour is any size and has spread to lymph nodes nearby, but has not spread anywhere else in the body (Any T N1 M0 or Any T N2 M0).
- Stage 4 – The tumour is any size. It may have spread to nearby lymph nodes. The cancer has spread to other parts of the body such as the liver or lungs (Any T Any N M1).
The grade gives doctors an idea of how quickly a cancer may develop. Doctors will look at a sample of the cancer cells under a microscope to nd the grade of your cancer.
- Grade 1 (low-grade) – The cancer cells tend to grow slowly and look similar to normal cells (they are well differentiated). These cancers are less likely to spread than higher grade cancers.
- Grade 2 (moderate-grade) – The cancer cells look more abnormal.
- Grade 3 (high-grade) – The cancer cells tend to grow more quickly and look very abnormal (they are poorly differentiated). These cancers are more likely to spread than low-grade cancers.
Treatments used for rectal cancer include surgery, radiotherapy, chemotherapy and sometimes targeted therapy. Often, a combination of treatments is used. When chemotherapy and radiotherapy are given together, it is called chemoradiation.
What treatment you have depends on the stage of the cancer and where it is in the rectum. It also depends on your general health and preferences.
Surgery to remove the cancer is one of the main treatments for rectal cancer. The operation usually involves removing part or all of the rectum, as well as nearby lymph nodes. If the cancer has grown into tissue or organs nearby, the surgeon may remove parts of these too. Sometimes, surgery is used to help with symptoms rather than cure the cancer. This may be if the cancer is causing a blockage in the bowel. Occasionally, surgery may be used to remove cancer that has spread to a distant part of the body, such as the liver or lungs. This is called secondary or advanced cancer.
Radiotherapy or chemoradiation may be given before or after rectal surgery. These treatments help to reduce the risk of the cancer coming back in the rectum, or in the tissues close to it.
Radiotherapy is also sometimes used to relieve symptoms, such as pain or bleeding. This is called palliative radiotherapy.
Sometimes, chemotherapy is given after surgery to reduce the risk of the cancer coming back. This is called adjuvant chemotherapy. If cancer has spread to the liver or lungs (secondary cancer), chemotherapy may be the main treatment. It is given to shrink the cancer and to control it for as long as possible. Some people with secondary cancer have chemotherapy to shrink the cancer before considering an operation to remove it.
Targeted therapies are sometimes used on their own or in combination with chemotherapy to control secondary cancer.
How treatment is planned
A team of specialists called a multidisciplinary team (MDT) will talk to you about the treatment they feel is best for your situation. This MDT will include a:
- surgeon who specialises in bowel cancers
- clinical oncologist who specialises in radiotherapy, chemotherapy and targeted therapies
- radiologist who helps to interpret x-rays and scans
- pathologist who advises on the type and size of the cancer
- stoma care nurse who helps to care for a stoma when someone has had a colostomy or ileostomy operation.
After the MDT discussion, your cancer specialist will talk to you about your treatment options. They will explain the main aims of treatment. These may be to try to cure the cancer, to help you live longer or to relieve symptoms. They will also tell you the possible short-term and long-term side effects of the treatments. Deciding which treatments are right for you is usually a joint decision between you and your cancer team. If a cure is not possible and the aim of the treatment is to control the cancer, it may be more difficult to decide what to do. You may need to discuss this in detail with your doctor. If you choose not to have the treatment, you can still be given supportive (palliative) care to control any symptoms.
Surgery is the most common treatment for rectal cancer.
You may have radiotherapy or chemoradiation before surgery. This can make it easier to remove the cancer. It also lowers the risk of the cancer coming back in the rectum or in the tissues close to it.
Surgery to remove rectal cancer
There are different techniques and types of operation that can be used. The type your surgeon recommends will depend on the stage of the cancer, where it is in the rectum and your general health.
After the operation, all the tissue that the surgeon has removed will be sent to a pathologist. They will check the tissue carefully for any cancer cells close to the cut ends. If they nd cancer cells in the margins, it is possible that not all of the cancer was removed during the operation. This is not common, but if it happens you may be offered a second operation or radiotherapy.
Open or laparoscopic surgery
Your operation may be carried out as open surgery or as laparoscopic (keyhole) surgery. Open surgery means the surgeon makes one large cut (incision). Afterwards, you have a wound that goes down in a line from just below your breastbone (sternum) to just below the level of your tummy button (navel). Some people have a wound that goes across their tummy (abdomen) instead.
In laparoscopic surgery, the surgeon makes four or five small cuts in the tummy rather than one big cut. They pass a laparoscope (a tube with a camera) into the tummy through one of the cuts. They then pass specially designed surgical tools through the other cuts to remove the cancer. Laparoscopic surgery is sometimes used when the cancer is small. It uses a specialised technique and is not available in all hospitals. Recovery from laparoscopic surgery is usually quicker than recovery from open surgery.
Total mesorectal excision (TME)
Stomas (colostomy or ileostomy)
During the operation to remove the cancer, an opening is sometimes made through the tummy (abdominal) wall. This lets the bowel connect to the surface of the tummy. It is called a stoma. It is round or oval, and it looks pink and moist. The stoma has no nerve supply, so it doesn’t hurt. Poo (stools) will no longer pass out of the rectum and anus in the usual way. Instead it will pass out of the stoma, into a disposable bag that is worn over the stoma. The stoma is made from an opening in part of the bowel. If the stoma is made from an opening in the colon, it is called a colostomy. If it is made from an opening in the small bowel (ileum), it is called an ileostomy. Stomas can be temporary or permanent. A surgeon may make a temporary stoma to allow the bowel to heal after surgery.
If you have a temporary stoma, you will usually have a second smaller operation a few months later to close the stoma and rejoin the bowel. This operation is called a stoma reversal. If the cancer is very low in your rectum and close to the anus, you are more likely to need a permanent stoma.
Very small, stage 1 rectal cancers can sometimes be removed using a local resection. This is a small operation to remove the cancer and some healthy tissue surrounding it.
The surgeon inserts an endoscope into the rectum to remove the cancer. An endoscope is a long, flexible tube with a tiny camera at the end. This surgery is called transanal endoscopic micro surgery (TEMS).
If the cancer is very low in the rectum and close to the anus, the surgeon may not need an endoscope. They may be able to remove the cancer by passing surgical instruments up the anus. This is called a transanal rectal resection.
An anterior resection is usually used for cancers in the upper and middle parts of the rectum (close to the colon). After the piece of bowel that contains the cancer is removed, the surgeon rejoins the two open ends of bowel. Some people may have a temporary stoma (usually an ileostomy) after this operation. A stoma reversal can usually be done a few months later.
Abdomino-perineal resection (APR)
This operation is usually used for cancers that are very low in the rectum (near to the anus). In order to remove all of the cancer, the surgeon needs to remove the rectum and anus. You will have a permanent stoma (usually a colostomy) after this operation. As well as the wound on your tummy, you will have a wound on your bottom where the anus has been closed.
Surgery for advanced rectal cancer
If the cancer has grown into other organs nearby, some people need a bigger operation to try to remove it. This is called a pelvic exenteration. Your doctor will explain more about this operation if it is appropriate for you.
If rectal cancer has spread to the liver, the most common treatment is chemotherapy. The aim is to shrink the cancer and control it for as long as possible. Some people may be able to have surgery to remove the part of the liver affected by cancer. This operation is called a liver resection. It can sometimes lead to a cure.
Liver resection is a major operation that takes three to seven hours. It is done by surgeons experienced in liver surgery (hepatobiliary surgeons) in specialist hospitals. This treatment is only suitable for a few people with secondary liver cancer.
Radiofrequency ablation (RFA)
If cancer has spread to the liver (secondary liver cancer) and can’t be removed with surgery, the main treatment is usually chemotherapy. This may be given with a targeted therapy. Other treatments, such as radiofrequency ablation, cryotherapy and radiotherapy, may also be used to treat secondary liver cancer. They may relieve symptoms and help to control the cancer for some time.
RFA uses heat to destroy cancer cells. An electrode (like a needle) sends an electric current (radiofrequency) to the tumour. The electric current heats the cancer cells to high temperatures and destroys (ablates) them. As the cancer cells die, the area that has been treated gradually shrinks and becomes scar tissue. RFA doesn’t always destroy all the cancer cells. Some people may need to be treated more than once. RFA can be repeated if the tumour starts to grow again. The most common way to give RFA involves a doctor placing one or more electrodes through the skin into the tumour. A CT scanner shows the position of the liver and tumours on a screen. This guides the doctor as they put each electrode into place. Sometimes, a similar treatment called microwave ablation (MWA) is used.
Treating a blocked bowel (bowel obstruction)
Sometimes, rectal cancer can narrow the bowel, which stops poo (stools) from passing through. This can cause symptoms such as tummy pain and vomiting. It usually needs to be treated urgently. It can be treated in two ways.
Stenting to relieve a blocked bowel
The surgeon uses a colonoscope to insert an expandable metal tube (stent) into the blockage. The tube then expands to hold the bowel open. The cancer causing the blockage can usually be removed with an operation at a later date.
Surgery to relieve a blocked bowel
Sometimes, a bowel obstruction is treated with an operation to remove the blocked section of bowel. The surgeon may remove the cancer at the same time or do this later in another operation. Most people will have a temporary or permanent stoma after this operation.
Bowel function after surgery
Most people have changes in how their bowel works after rectal surgery. If you had a local resection, your bowel will usually recover quite quickly. After TME surgery, it will take longer. It could take several months for your bowel function to get into a regular pattern. It may never be the same as it was before the cancer. But in time, it should settle into a routine that you recognise as normal for you. If you had radiotherapy or chemoradiation before or after rectal surgery, this will also affect your bowel. This could mean it takes longer to get back to a regular bowel habit. After rectal surgery, you may experience one or more of the following changes:
- needing to poo several times a day (more frequent)
- feeling that you can’t wait when you need to poo (urgency) • diarrhoea or constipation
- losing control over when your bowels open (incontinence) • dif culty telling the difference between wind or stools
- feeling bloated or passing a lot of wind
- having a sore bottom.
These effects usually improve over time. Tell your surgeon if you are having problems, or if your bowel is not settling into a routine.
If you have a stoma
Having a stoma is a big change to your body, whether it is temporary or permanent. It can take time to adjust to. The stoma will be swollen at first, but will shrink to its final size within a few weeks. Learning to look after a stoma takes time and patience. You may want to have a family member or friend with you while you are taught how to care for your stoma. This means they will know how to help you at home, if needed.
If you have a temporary stoma, you can usually have an operation to reverse the stoma when your treatment is over. This means you will pass poo (stools) from your bottom again. The timing of a stoma reversal operation varies from person to person. It can range from a few months after the stoma was made, to one or two years later. How stoma reversal is done depends on whether you have a loop stoma or an end stoma.
To reverse a loop stoma, the surgeon closes the opening in the loop of bowel that was used. They then remove the stitches holding the loop of bowel in place on the skin. The bowel goes back inside the tummy (abdomen). To reverse an end stoma, the surgeon removes the stitches that are holding the piece of bowel up to the skin. The piece of bowel is rejoined to the rest of the bowel inside the tummy.
After a stoma reversal, it may take some time for your bowel habit to get back to normal.
Radiotherapy uses high-energy rays to destroy cancer cells while doing as little harm as possible to normal cells. Radiotherapy only treats the area of the body that the rays are aimed at. It is often given in combination with chemotherapy. This is called chemoradiation. Chemotherapy makes cancer cells more sensitive to radiotherapy. Radiotherapy does not make you radioactive. It is safe for you to be with other people, including children, throughout your treatment.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. It is often given in combination with radiotherapy. Chemotherapy may be given:
- after surgery, to reduce the risk of cancer coming back
- before surgery (if you are having cancer removed from the liver or lungs), to shrink the cancer and reduce the risk of it coming back
- as the main treatment (if it has spread to parts of the body such as the liver or lungs), to try to control it for as long as possible.
Targeted therapies interfere with the way cancer cells grow. They are sometimes called biological therapies. Targeted therapies are sometimes used to treat bowel cancers that have spread to other parts of the body. They may be given on their own or with chemotherapy. Targeted therapies that may be used include:
- cetuximab (Erbitux®)
- panitumumab (Vectibix®)
- bevacizumab (Avastin®)
- aflibercept (Zaltrap®)
- ramucirumab (Cyramza®)
- egorafenib (Stivarga®)