Side effects of surgery

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Side effects can happen with any type of cancer treatment, but everyone’s experience is different. Some people have many side effects. Other people have few or none at all.

Side effects can develop any time during, immediately after or a few days or weeks after surgery. Sometimes late side effects develop months or years after surgery. Most side effects will go away on their own or can be treated, but some may last a long time or become permanent.

Different types of surgery can cause different side effects and sometimes complications (an unexpected medical problem). The approach or technique that the surgeon uses can also cause certain side effects. The side effects you have after surgery will also depend on your overall health and other cancer treatments you receive. Your surgeon and healthcare team will work together to try to limit the side effects you have after surgery and how severe the side effects are.

Some people worry that cancer cells can spread during a biopsy or when a tumour is exposed to the air during surgery. Exposure to air does not cause cancer to spread. There is only a very small chance that a biopsy will cause cancer to spread. Doctors are careful to prevent cancer from spreading into healthy tissue during surgery. The benefits of doing the surgery usually far outweigh the risks.

Side effects of surgery will depend mainly on:

  • the type and location of the surgery
  • what is done or removed during surgery
  • your overall health
  • the effects of other cancer treatments (for example, tissue treated with radiation may not heal well after surgery)

The risk of side effects is usually lower in children than in adults because children can usually move and walk around soon after surgery. Most children who have surgery will not experience serious side effects.

Tell your healthcare team if you have these side effects or others you think might be from your surgery. The sooner they are aware of any problems, the sooner they can suggest ways to help you deal with them.


Most people have some pain after surgery. It can take time for pain to go away after surgery. It depends on the type of surgery done and how well you heal or cope with pain. Pain medicines may be given to control pain.

Check with your healthcare team if pain does not go away or pain medicines do not relieve the pain.

Find out more about pain and how to manage it.

Sore throat

If you are given a general anesthetic, a tube may be placed in your windpipe (trachea) to help you breathe during surgery. Putting this tube in and taking it out may cause a sore throat. This is a temporary side effect that usually goes away soon after surgery.


Bleeding (hemorrhage) may occur if a blood vessel is not sealed off during surgery or if you have a blood-clotting disorder. The healthcare team frequently checks bandages and drains for heavy bleeding right after surgery. If bleeding is severe, you may have to go back to the operating room so the surgeon can find where the bleeding is coming from and stop it.

A small amount of bloody drainage may be expected after surgery. Tell your healthcare team when you are concerned about bleeding.

Blood clots

Blood clots can form in the deep veins of the legs (called a deep vein thrombosis, or DVT). This may happen because you are in bed for a long time and don't move very much after surgery, or because of other issues. A blood clot can be very serious if it breaks off and travels to other parts of the body, such as a lung (called a pulmonary embolism). To help lower the chance of blood clots, your healthcare team will get you to move your legs and ankles after surgery. They will get you up and moving around soon after surgery.

People who are at high risk for developing blood clots may be given low doses of a blood thinner medicine, such as heparin, to help reduce the risk. Stopping smoking before surgery also helps lower the risk of developing blood clots.

Tell your doctor or healthcare team if you have any redness, swelling, pain or cramps in your legs.

Nausea and vomiting

Nausea and vomiting may happen from the general anesthetic used during surgery. Medicines may be given to prevent and control nausea and vomiting. Nausea and vomiting are usually temporary side effects and often go away a few days after surgery.

Find out more about nausea and vomiting.

Problems urinating (peeing)

Sometimes people have problems urinating (peeing) after surgery. This is also called urinary retention. This side effect can be caused by certain drugs used for anesthesia or to control pain.

The healthcare team will monitor when and how much you urinate for a short time right after surgery. If you cannot urinate, they may place a tube called a catheter to drain the bladder until you urinate again.

Find out more about bladder problems and how to manage them.

Wound infection

Some people develop a wound infection after surgery. This is not a common side effect, but it can happen after any type of surgery. Sometimes tubes are placed into the wound to drain extra fluid. Antibiotics may be given to help prevent or treat an infection. Wound infections are a temporary side effect of surgery.

Tell your doctor or healthcare team about signs of infection, such as redness, pus or foul-smelling drainage, swelling or tenderness where the cut (incision) was made or if you have a fever.

Wound separation

The edges of a wound are usually held in place with stitches or staples until the surgical cut heals enough to remove them. But the edges of the wound may separate, or come apart, after surgery (called dehiscence). Minor separation of the skin edges may not be a serious problem. But separation of underlying muscle or fat edges can be more serious. It may lead to an organ or tissue sticking out through the underlying tissue (called a hernia).

Try to avoid strenuous physical activity for 6 to 8 weeks after surgery to help prevent wound separation. Tell the doctor or healthcare team if the cut from your surgery doesn’t heal, if a gap opens in the cut or if it feels like the cut has come open.


Scarring happens as part of the healing process after surgery. Scars are permanent, but they can fade over time and become harder to see. They can be visible for a long time after surgery.

For many types of cancer, surgeons can use less extreme, or less radical, types of surgery. This usually means that they make a smaller cut and there is less scarring. Newer techniques limit the damage to normal tissues, and reconstructive surgery helps reduce noticeable physical changes from surgery.

Gastrointestinal (GI) problems

The gastrointestinal (GI) tract may not work as it should because it was affected by drugs used for pain and the surgery. This can cause a problem called paralytic ileus. Paralytic ileus is when the intestine becomes paralyzed or inactive and stomach contents cannot move through it.

The healthcare team will check your bowel activity after surgery. You will gradually be allowed to take in fluids and foods by mouth (orally).

Lung problems

Lung problems can happen for many reasons, including where on the body the surgery happened, the type of surgery done, lung problems you already have or if you smoke. The 2 main types of lung problems are lung infection (pneumonia) and collapsed lung (atelectasis).

Stopping smoking before surgery helps prevent lung infections and a collapsed lung. Frequent deep breathing, coughing and turning in bed can help lower the chance that you will have lung problems after surgery. Some people may be given a special device called an incentive spirometer to breathe into. This device helps them take deep breaths.

Tell your doctor or healthcare team if you have shortness of breath, a fever or a cough after surgery.

Find out more about lung problems.

Nerve pain

Nerve pain may occur when surgery is done on tissues close to nerves. Nerve pain can develop long after surgery is over and may last a long time. This side effect may be treated with pain medicines or pain-relieving therapies, such as acupuncture.

Nerve damage

Some types of surgery may damage or remove nerves. This can cause a loss of feeling (numbness) or changes in feeling. Nerve damage can develop long after surgery is over and may last a long time.

There is no specific treatment for nerve damage, but some feeling may return over time. People with nerve damage may be more prone to injury because they do not feel pain as they used to. Some people may have surgery to reconstruct the nerve if nerve damage affects how well certain organs work.

Swelling of the limbs

Swelling of limbs (called lymphedema) can happen when lymph nodes are removed and fluid builds up in the tissues. Lymphedema may develop long after surgery is over and may last a long time.

Talk to your healthcare team about ways to manage lymphedema. Elevating the limb and wearing compression bandages can help to reduce the lymphedema.

Find out more about lymphedema.


Shock is a dangerous side effect that can happen during or after surgery. There are different types of shock, including septic shock and shock from a low amount of blood flowing throughout the body (low blood volume).

Treatments used for shock will depend on the type of shock that happens.

Reaction to anesthetic

Reactions to anesthetics may happen, but they are rare. Signs and symptoms can include wheezing, a fever and low blood pressure.

Reactions to anesthetics are usually temporary. People who have a reaction may be given medicines to manage the symptoms.

Expert review and references

  • Gary Groot, MD, PhD, FRCSC

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