Problems after anal cancer surgery

There is a risk of problems or complications after any operation.

Possible problems after anal cancer surgery include a collection of puss (abscess) and slow wound healing. Other risks include infection, blood clots and bleeding.

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. You will have antibiotics to reduce the risk of developing an infection after surgery. Tell your doctor or nurse if you have any symptoms of infection.

They 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

Rarely for an infection in your wound, you may need another operation.

Blood clots

Blood clots (deep vein thrombosis, DVT) 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, causing a blockage there (a pulmonary embolism). Symptoms include:

  • shortness of breath

  • chest pain

  • coughing up blood

  • feeling dizzy or lightheaded

If you have any symptoms of a blood clot when you are at home, you should contact a doctor immediately. This might be your emergency GP service. Or call 999 or go to your nearest accident and emergency department (A&E).

To prevent clots it's important to do the leg exercises that your nurse or physiotherapist taught you. 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 4 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. Or a district nurse might come to your home to do them.

It's important to continue wearing compression stockings if you have been told to by your doctor.

Bleeding in your pelvis or abdomen

You'll have some blood loss during your operation. Sometimes you may need a blood transfusion for this.

There is a small risk of internal bleeding after the operation. This is rare. If this happens you may need a second operation.

Your nurse will check you regularly after surgery for signs of blood loss.

Chest and breathing problems

Chest infections, including pneumonia, can be serious. 

You can lower your risk by:

  • stopping smoking before your operation
  • getting up and moving as soon as possible after your operation
  • doing any breathing exercises your physiotherapist teaches you

If you get an infection you have antibiotics to treat it. 

Sexual or urinary problems

The nerves controlling your sexual organs and your ability to pee (pass urine) are in the tummy (pelvis). There is a risk that some of these nerves might get damaged during an abdominoperineal resection (APR).

Your surgeon will take extra care not to damage the nerves. Talk to your nurse or surgeon if you are worried about this. They can tell you what the risk might be in your situation.

Other problems

  • a collection of puss or infected fluid surrounded by inflamed tissue inside the tummy (an abscess). Symptoms include a high temperature or tummy pain. Contact your doctor or nurse immediately if you have this. You will need antibiotics.
  • a slowing of the movement of the bowel (ileus) – you might not break wind or have poos (stools)
  • a blockage of the small bowel (bowel obstruction). Symptoms can include feeling full, having tummy pain or being sick (vomiting).
  • problems with a stoma
  • a wound that is slow to heal
  • a wound that opens partially or completely
  • Abdominoperineal Resection

    R Wei and others

    StatPearls Publishing. January 2022.

  • Management of perineal complications following an abdominal perineal resection

    UpToDate website

    Accessed July 2022

Last reviewed: 
28 Jul 2022
Next review due: 
28 Jul 2025

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