A study looking at different techniques to protect the heart from radiation during radiotherapy for breast cancer (The HeartSpare Study - Stage 1)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Breast cancer




Phase 2

This study is looking at different ways of holding your breath during radiotherapy for breast cancer, and at the position you lay on the radiotherapy couch. These techniques may lower the risk of long term side effects to the heart.

More about this trial

Having radiotherapy after surgery for breast cancer can help stop the cancer coming back. Your team will take great care to plan your radiotherapy so that the beam reaches as little surrounding tissue as possible, because this type of exposure to radiation can cause side effects months, or even years after treatment. The affected tissue may include your lung, ribs and, if the cancer is in your left breast, your heart.

Doctors want to find ways of lowering the risk of side effects as much as possible. This study is looking at improving radiotherapy treatment for women with left sided breast cancer, which has a greater risk of long term side effects to the heart. Holding your breath in a particular way may reduce the amount of heart tissue exposed to X-rays. Women are taught to hold their breath for about 20 seconds while they have radiotherapy. Breathing in pulls the heart away from the radiotherapy beam. Also, lying face down (prone) on the radiotherapy couch rather than on your back may help to reduce the amount of heart tissue exposed to X-rays in larger breasted women. But doctors do not know whether a certain breathing technique, or position, works best. The aim of this study is to find out if one method is better than the other at reducing radiation to the heart tissue.

Who can enter

You may be able to enter this study if

  • You have invasive breast cancer Open a glossary item, your tumour is no bigger than 5cm in size (T stages T1 to T3b) and if you have any cancer cells in lymph nodes in your armpit, these lymph nodes are not stuck to any other structure in your armpit (N stages N0 to N1) – you can check this with your doctor or you have a very early type of breast cancer called ductal carcinoma in situ
  • Your cancer is in your left breast
  • Your surgeon is confident that they have removed all microscopic traces of your cancer, either with surgery to remove your whole breast (mastectomy), or with surgery to just remove the cancer
  • Your doctor would like you to have radiotherapy to the affected breast after surgery, or to the chest wall on your left side if you had a mastectomy
  • You are well enough to carry out all your normal activities, apart from heavy physical work (performance status of 0 or 1)
  • You think you would be able to hold your breath for 20 seconds after training
  • You are at least 18 years old

You cannot enter this study if

  • You have cancer that has spread to another part of the body, apart from the breast and lymph nodes under the arm (breast cancer TNM stage M1)
  • You need to have radiotherapy to treat cancer in your lymph nodes
  • Doctors could see traces of cancer from your sentinel lymph node biopsy, and you have not had these lymph nodes removed from your armpit
  • You have ever had any radiotherapy to the area above the sheet of muscle under your rib cage (diaphragm Open a glossary item)

Trial design

This study is split into parts 1a and 1b. Part 1a looked at 2 breathing techniques. Part 1b is using the best breathing technique found in part 1a and comparing it with the technique of lying face down on the radiotherapy couch.

Women taking part in 1a laid on their backs and put their arms above their heads. During one scan, they breathed in, holding their breath for the length of the scan. During the other scan, they also held their breath, but breathed through a mouthpiece linked to the CT scanner. The scanner was triggered when they took the breath in.

The team found that both techniques worked as well as each other. All the patients' hearts moved out of the radiation field during the breath hold, and the radiation doses to the heart tissue were low. Women taking part found that holding their breath for the length of the scan (the voluntary breath hold) was easier than through the mouthpiece linked to the scanner. This technique was also cheaper. So, the team will use the voluntary breath hold for part 1b.

If you join part 1b, you lie on your back for one scan with your arms raised above your head. For the other scan, you lie on your front. During the scan on your back, the team will ask you to take a breath in and hold it for up to 20 seconds (they will teach you how to do this). The staff will then help you turn over and lie on your front on a special couch. The couch allows your affected breast to hang down through a gap in the couch. This shouldn’t be uncomfortable, but may feel a bit odd to begin with. You then have a CT scan in this position.  

Although these scans only take about 20 seconds, you will need to lie in the same position for between 10 and 15 minutes for each scan. For everyone in both parts, after these scans the radiographer will need to make some tiny permanent marks (tattoos) on your skin. These will be over your breast bone and one each side of your chest. And, if you are in part 1b, you have 3 or 4 more tiny tattoos - 2 either side of your chest and one or 2 over the skin on your back. Everyone having radiotherapy has these marks. They help make sure you are in the right position for treatment each time.

Everyone will fill out a short questionnaire asking how they found each technique. The team will then plan your radiotherapy using the scan information, which takes a few days.

Women joining part 1b, during their first 7 sessions of radiotherapy, use either the breathing technique or the lying face down technique they used during the CT scans. For the remaining 8 sessions, you will switch, and use the other technique. The method everyone starts with will be decided randomly. Neither you nor the radiographer will be able to choose this.

On your first day of treatment, you have a low dose CT scan of your breasts just before treatment. This takes 2 minutes. For the study, you have a series of further CT scans. Women in part 1b will have low dose CT scans before sessions 3, 5, 7, 8, 10, 12 and 14. This will give the team more detailed information on your position throughout your treatment. You also fill out one or more questionnaires, depending on the stage you are in, asking how comfortable you find the sessions.

After the study, everyone will continue to see their regular cancer specialist in the same way as before.

Hospital visits

You should not have to make any extra hospital visits to take part in this study. But some of your appointments will take a little longer. A standard breast radiotherapy treatment takes 5 to 10 minutes. On the days you have extra CT scans, you should allow 15 to 20 minutes.

Side effects

People joining part 1b will have one extra radiotherapy planning CT scan, and 8 extra low dose CT scans during treatment. The radiation dose from the extra scans is about 1,000 times less than the dose used in radiotherapy treatment, and is unlikely to cause you any harm.

It is possible that you may find holding your breath difficult or uncomfortable. The team will assess you when you come for your planning CT scans. If you find it difficult, they will arrange for you to have standard breast radiotherapy, rather than entering the study.

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

Dr Anna Kirby

Supported by

NIHR Clinical Research Network: Cancer
NIHR Research for Patient Benefit (RfPB) Programme
The Royal Marsden NHS Foundation Trust

Questions about cancer? Contact our 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.

Harriet wanted to try new treatments

Picture of Harriet

“I was keen to go on a clinical trial. I wanted to try new cancer treatments and hopefully help future generations.”

Last reviewed:

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