Surgery for anal cancer
It is important to tell your doctor or nurse if you have any problems after surgery. Many problems are minor but some can be life threatening. Treating them as soon as possible is important.
You are at risk of getting an infection after an operation. This includes a wound, chest or urine infection. Symptoms can depend on where the infection is. Tell your doctor or nurse if you have any symptoms of infection.
These include:
a high temperature
shivering
feeling hot and cold
feeling generally unwell
cough
feeling sick
swelling or redness around your wound and your wound might feel hot
a strong smell or liquid oozing from your wound
loss of appetite
cloudy smelly pee
If you get an infection, your doctor gives you antibiotics to treat it.
Sometimes for an infection in your wound, you may need another operation. But this is rare.
Rarely, your body can have an overwhelming response to an infection. This is called sepsis and it can be life threatening.
The following symptoms could be due to sepsis:
Slurred speech or confusion
Extreme shivering or muscle pain
Passing no urine (in a day)
Severe breathlessness
It feels like you’re going to die
Skin mottled or discoloured
Read more about infections and sepsis
As well as an infection, the wound around where your anus was may:
be slow to heal
open partially or completely
Your doctor and nurse can manage these using special dressings. Sometimes this may include a dressing with a small pump included. This is called a VAC dressing.
After surgery for anal cancer, you can get an abscess in your tummy (abdomen). Symptoms include a high temperature or tummy pain. Contact your doctor or nurse immediately if you have either of these symptoms.
Blood clots are also called a deep vein thrombosis or DVT. They are a possible complication of having surgery because you might not move about as much as usual. Clots can block the normal flow of blood through the veins. Let your doctor or nurse know if you have an area in your leg that is swollen, hot, red or sore.
There is a risk that a blood clot can become loose and travel through the bloodstream to the lungs. This causes a blockage called a pulmonary embolism. Symptoms include:
shortness of breath
chest pain
coughing up blood
feeling dizzy or lightheaded
To prevent clots it's important to do the leg exercises that your nurse or taught you. And to move around as much as possible. Your nurse might also give you an injection just under the skin to help lower the risk whilst you are in hospital. You might need to carry on having these injections for a few weeks, even after you go home. This depends on the type of operation you had.
Your nurse might teach you to do these injections yourself before you go home. They will make sure you are comfortable doing them. Or a district nurse might come to your home to do them.
It's important to continue wearing your anti embolism stockings if you have been told to by your doctor.
It’s normal to lose some blood during an operation. Depending on how much you lose, you might need a during or after surgery to replace it.
There is a small risk of bleeding inside your body after the operation. This is rare. But if this happens you may need a second operation.
You can also get bleeding from your wounds.
Your nurse will regularly check you for signs of bleeding after surgery.
After surgery on your abdomen your bowel may become slow and sluggish. Doctors call this post operative ileus.
Ileus can happen 2 to 3 days after surgery. Symptoms include:
a swollen abdomen
abdominal pain
passing no wind or poo
feeling or being sick
If you get ileus, your doctor asks you to stop eating and drinking for a short time. And they give you fluids into your bloodstream (intravenously). You will also be encouraged to walk around. This can help the bowel to start working again. Sometimes your doctor may suggest a tube down your nose and into your stomach to help control the symptoms.
Your bowel normally starts working again after a few days. Then you can start drinking sips of water. You slowly build up the amount you drink daily until you can start eating a light diet.
Rarely, scar tissue in your abdomen can cause your small bowel to stick together. This can cause your bowel to become blocked (bowel obstruction) so poo cannot pass through it. The symptoms are the same as ileus. But it tends to happen months or years after surgery.
Bowel obstruction is an emergency. You should see your doctor quickly or go to A&E at your nearest hospital if you think you have a bowel obstruction.
Read more about bowel obstruction
The nerves controlling your sexual organs and your ability to pee are in your pelvis. There is a risk that some of these nerves might get damaged during an abdominoperineal resection.
This can cause problems for men such as difficulty getting an erection. And women can have vaginal dryness. Or a change of sensation in the vagina when having sex. It can also cause both men and women to have difficulty peeing.
Your surgeon takes extra care not to damage the nerves during the operation. Talk to your nurse or surgeon if you are worried about this. They can tell you what the risk might be in your situation.
Find out about sex after treatment for anal cancer
If you have a colostomy after surgery, your stoma nurse will show you how to look after it and what problems to look out for.
Problems with a colostomy can include:
not enough blood getting to your stoma – symptoms normally start in the first 24 hours after your operation. Your doctors and nurses will check for signs of this
your stoma starting to come further out from your abdomen (prolapse)
your bowel pushing through the abdominal muscle around the stoma (hernia)
Your stoma nurse tells you who to contact if you have any problems with your colostomy when you go home.
Read about having a colostomy for anal cancer
We have more information on possible problems after surgery for cancer, including:
pain
different types of infection
Find out more about possible problems after surgery for cancer
Last reviewed: 11 Sept 2025
Next review due: 11 Sept 2028
Surgery is the main treatment for some cancers. You may also have it for other reasons. But what happens before, during and after surgery, normally depends on the type of cancer and your general health.
There is a risk of complications after any surgery. This includes infection, blood clots and pain. Other problems can depend on what operation you have.
You may need surgery if anal cancer comes back. Or hasn't all gone after chemoradiotherapy. Some people have surgery as the main treatment for stage 1 cancer in the anal margin.
After treatment, you have regular follow up appointments at the hospital. You might also have examinations and tests including scans.
If your surgeon removes your anus, they open the end of your bowel onto your skin (stoma). This is a type of stoma called a colostomy. You wear a special bag over the stoma to collect the poo.
Anal cancer is cancer that starts in the anus. The anus is also called the anal canal.

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