A trial looking at surgery to remove the whole thyroid or part of the thyroid (HoT trial)

Cancer type:

Thyroid cancer




Phase 3

This trial is comparing two types of surgery for thyroid cancer. It is comparing removing the whole thyroid with removing only the side (lobe) that the cancer is in. 

It is open to people with thyroid cancer that:

More about this trial

The thyroid has 2 lobes.
Doctors use surgery to remove cancer from the thyroid. There are 2 types of surgery that surgeons use:

  • removing the whole thyroid gland - this is a total thyroidectomy 
  • removing the lobe that the cancer is in – this is a lobectomy or hemithyroidectomy 

After a total thyroidectomy you might have radioactive iodine treatment

You will also need to take hormone therapy for the rest of your life. 
This is because your thyroid produces hormones Open a glossary item that the body needs to work properly. You may also need to take vitamin D and calcium tablets. 

After a lobectomy or hemithyroidectomy you may not need to have hormone therapy. This is because the remaining part should produce enough hormones. 

Some people find out they have thyroid cancer by chance. They have problems with their thyroid and have tests or procedures to find out why. One of these  procedures might be removing part of their thyroid.

There are 2 groups of people in this trial.

Group 1
This group is for people who had one lobe of their thyroid removed (hemithyroidectomy) because they have had problems with their thyroid. They found out that they have thyroid cancer after surgery. 

Group 2
People who have had a thyroid cancer diagnosis before surgery. 

The aims of this trial are to find out:

  • whether a hemithyroidectomy is as good as a total thyroidectomy
  • what the chances are of the cancer coming back after hemithyroidectomy compared to total thyroidectomy
  • what the need is for thyroid replacement therapy after both types of surgery
  • what the effects of both types of surgery are on  quality of life Open a glossary item
  • which surgery has the fewest complication and is most cost effective for the NHS

Who can enter

The following bullet points are a summary of the entry conditions for this trial. Talk to your doctor or the trial team if you are unsure about any of these. They will be able to advise you. 

Who can take part
You may be able to join this trial if you:

  • were having thyroid problems and had surgery to remove 1 lobe and then the diagnosis was thyroid cancer  
  • have thyroid cancer but have not had surgery yet

And all of the following apply. You:

  • have a differentiated type (papillary, follicular or Hurthle cell) of thyroid cancer that is completely in one lobe (stage 1b or 2) and is no bigger than 4cm across
  • are at least 16 years old 

Who can’t take part

You cannot join this trial if any of these apply. You have:

  • stage 1a differentiated thyroid that is 1cm or less across 
  • anaplastic, poorly differentiated or medullary thyroid cancer 
  • had surgery and there is a very small amount of cancer left that the doctor could see. You might be able to join if there is the need to use a microscope to see any cancer left. 
  • cancer that has spread out into the thyroid from where it started 
  • cancer that has spread to another part of the body such as the lung or to the surrounding tissue outside the thyroid
  • cancer that has spread to the lymph nodes

Trial design

This is a phase 3 trial. The team need 456 people to join. 

The researchers need 2 different groups of people. Which group you are in depends on whether you have already had a hemithyroidectomy or not. 

This is a randomised trial. Neither you nor your doctor chooses which treatment group you are in. 

There are 2 treatment groups for each group of people. A computer puts you into one of the 2 treatment groups.

Group 1
This is for people who have already had a surgery to remove 1 lobe of the thyroid and then had cancer diagnosed. The treatment groups are:

  • your doctor monitors you regularly (surveillance)
  • you have a second surgery to remove the rest of the thyroid (called a completion thyroidectomy)

Group 2
People diagnosed with thyroid cancer before having surgery. You have either: 

  • surgery to remove the lobe in the thyroid that has the cancer in it (hemithyroidectomy) 
  • or you have surgery to remove all of the thyroid (total thyroidectomy)

Your doctor will tell about your surgery and how long you might be in hospital. You have a general anaesthetic Open a glossary item to have surgery. 

After surgery you might have: 

  • radioactive iodine treatment
  • hormone medication to replace the hormones your thyroid makes
  • calcium and vitamin D tablets

Your doctor will talk to you about these if any apply to you. 

Quality of life
You fill in 5 questionnaires before having surgery:

  • before your thyroid surgery (if applicable)
  • 2 to 4 weeks after surgery
  • 6 months after surgery
  • and then every year for up to 6 years

The questions ask about:

  • your general health and wellbeing
  • how well your voice works

These are quality of life questionnaires.

Web-based ‘App’ sub study
The team might ask you to take part in an optional sub study. 

The sub study looks at using a web-based application (‘app’) to fill in the quality of life questionnaires. If you agree to take part, you can access the web-based app on your mobile phone or tablet. When you are due to complete the questionnaires the app sends you a text (SMS) message alert.

The trial team ask the first 30 to 50 people on the HoT trial to use the ‘app’ as part of a pilot phase. If they agree they will be able to use the app to complete the trial questionnaires.

After this anyone who agrees to take part in the sub study are randomly into 1 of 2 groups. Half of the people:

  • use the app to complete the questionnaires
  • won’t use the app and will complete the paper questionnaires as usual 

The aim of the sub study is to find whether using the app is easier and better for people than completing the paper questionnaires. 

You don’t have to agree to join the sub study.

You can use the paper version of the questionnaires throughout the trial or you can switch from the web-based app to the paper questionnaires at any time you wish.

Hospital visits

You see the doctor for a physical examination Open a glossary item before joining the trial and before surgery. 

People in group 1 not having a second surgery
You have a follow up appointment to see the doctor 6 months after your hemithyroidectomy. And then you see them once a year for up to 6 years.   

Follow up for people in groups 1 and 2 having surgery 
After surgery you see the doctor 2 to 4 weeks for blood tests and to see how you are. You then see the doctor:

  • 6 months after surgery
  • once a year for up to 6 years

During follow up everyone has these tests:

  • a physical examination
  • blood tests
  • ultrasound of the neck

After 6 years your doctor will tell you how often they need to see you.

Side effects

The trial team monitor you during treatment and afterwards. Contact your advice line or tell your doctor or nurse if any side effects are bad or not getting better. 
The most common side effects of having thyroid surgery include:

  • numbness over the area
  • infection such as wound infection or chest infection
  • a blood clot or bleeding in the area
  • swelling in the area

We have information about thyroid surgery.



Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Professor Dae Kim

Supported by

University College London (UCL)
National Institute for Health Research (NIHR)
Butterfly Thyroid Cancer Trust Charity
Thyroid Cancer Support Group Wales
University College London Clinical Trials Centre (UCL-CTC) 

If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Last reviewed:

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