Diathermy (electrocautery)

Diathermy treatment uses an electrical current to destroy cancer cells. It is also called electrocautery or thermocautery.

You might have diathermy treatment if your cancer is blocking an airway and making it difficult for you to breathe. The treatment helps you to breathe more easily afterwards.

You normally have treatment in the endoscopy unit at the hospital. And you’ll have it under a general anaesthetic. This means you’ll be asleep and won’t feel anything.

You might have diathermy alongside other treatments.

Preparing for diathermy treatment

Your doctor or specialist nurse explains what happens and how they do the treatment. They ask you to sign a form saying that you agree to have the procedure. You can ask them any questions that you have. Tell them about any medicines you are taking.

You shouldn’t eat or drink anything except water for 4 to 6 hours before the treatment. You can drink water until 2 hours beforehand.

Having diathermy treatment

A nurse puts a small tube called a cannula into a vein in the back of your hand. They go with you to the endoscopy or x-ray department.

You have the general anaesthetic medicine through the cannula in your hand. 

When you’re asleep your doctor gently puts a long flexible tube called a bronchoscope into your airway. They pass a small diathermy probe down the bronchoscope tube.

Diagram showing a bronchoscopy

The probe passes an electrical current into the tumour. This produces heat that destroys the cancer cells.

The doctor takes out the bronchoscopy tube.

After diathermy treatment

You stay in the endoscopy department until the anaesthetic wears off.

You might feel a bit drowsy and confused but you won’t remember any of the treatment.

You might wear an oxygen mask for a short time.

A nurse then takes you back to your ward.

You might have to stay in hospital overnight.

Side effects

Soreness and pain

You might have a sore throat. Taking painkillers for a few days helps. Tell your nurse or doctor if you still have pain.


You might have some slight bleeding and have some blood in your sputum (phlegm). It might give you a metallic taste in your mouth. This usually gets better over a few days.

Rarely, some people have a lot of bleeding after diathermy.

Tell your doctor if you’re coughing up blood.

Possible risks

Your doctor will talk to you about the risks and benefits of having diathermy. It’s a safe procedure but every treatment has potential risks and side effects.

Difficulty breathing

Diathermy should make it easier for you to breathe. Let your doctor know if you find it more difficult.

Chest infection

Let your doctor know if you develop any signs of a chest infection. This includes having a high temperature and your phlegm (sputum) changing colour.

If the cancer blocks the airway again

You can have the treatment again if the tumour grows back. Or your doctor might suggest other treatments.

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