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A guide to your Magseed guided wide local excision

Patient information A-Z

Magseed next to grains of rice

Who is the leaflet for?

This leaflet is for patients undergoing a Magseed-guided wide local excision procedure. The leaflet will provide further information on Magseed and the procedures to insert and remove it.

Why have I been invited to take part?

You have been invited to take part as you will be having a wide local excision to remove a cancer that is too small to be felt. For the surgeon to know the exact location of the tumour, a small marker will be required. There are a number of aids that can be used to ‘mark’ it. One of these is the Magseed marker.

We would like to see how well the Magseed works and whether it would be beneficial to our patients compared to our standard wire localisation technique. So is it because the patient needs it or because the patient has been identified as someone who would be useful to trial the device? The patient needs it to help locate the cancer. If they didn’t use this technique, another would be used.

Localisation techniques

Due to imaging and screening advancements, breast cancer is often caught at earlier stages. However, early detection means that cancers are typically smaller and therefore harder to locate during surgery. Studies have shown that about 50% of all lesions are “non-palpable”, which means your surgeon cannot find them by touch alone.

The traditional process is to place a wire in the tumour to guide the surgeon to the lesion during the operation. This technique, called a Wire Guided Localisation, is carried out over 30,000 times per year in the UK, and despite being in general use since the 1960s, it has some limitations:

  • The wire is usually placed on the morning of your surgery and requires you to attend a separate radiology appointment before your surgery.
  • There is likely to be a waiting period before surgery, during which the wire will be protruding from your breast.
  • You will be advised to slightly restrict your movements, so that the wire is not accidentally dislodged before the tumour is removed.
  • The wire guides your surgeon to the tumour during the operation. This can limit the surgical approach, and impact the cosmetic result.

There are several devices available in the UK for lesion localisation, one of which is Magseed technology. This system helps increase surgeons’ ability to precisely locate tumours during surgery, which increases the probability of complete removal of the affected area.

Magseed is used routinely in many centres worldwide, including those in the UK and it has been approved by the National Institute for Health and Care Excellence (NICE).

How does the Magseed work?

Magseed is 5mm seed made of surgical grade stainless steel. It is placed into small breast cancers that cannot be felt by the surgeon so that they can be located accurately during surgery.

The Magseed® marker will be placed in the centre of your tumour well in advance of your surgery. Once you are in the operating room, your surgeon will first use your mammogram images to give them a rough idea of where the tumour is located in your breast. A probe (called a Sentimag) will then be used to detect the signal from the Magseed® marker, which will enable them to accurately locate the seed. This enables the tumour to be removed accurately and completely.

What does having a Magseed placement involve?

The Magseed is approximately the size of a grain of rice. It is similar to the hydromark clip that may have been placed at the time of your biopsy to mark your cancer site.

You will be asked to come in to the breast unit a week before surgery to see the radiologist and have the Magseed inserted under local anaesthetic. A mammogram will be taken afterwards to confirm the site.

During the placement your clinician will:

  • Confirm the location of the tumour using imaging (mammography or ultrasound)
  • Use a local anaesthetic to numb the targeted area of your breast
  • Introduce the Magseed through a small needle under image guidance
  • Confirm the placement of the Magseed

You will not feel the Magseed after it has been placed and you can resume normal activity.

You will then return for your surgery the next week. The surgeon will use a probe during the operation that can detect the magnetic signal from the Magseed. They will remove the tumour, the Magseed and the clip if you had one placed at the time of surgery.

You will then be seen two weeks later for results and review by your surgical team .

What are the risks of Magseed?

There may be some discomfort at the time of insertion however you will be given a local anaesthetic to minimise this. The alternative standard localisation we offer, which is wire placement is undertaken using a similar technique and also carries the possibility of discomfort.

With any localisation device including a wire or Magseed there is a risk of it moving from the intended placement site which is why a mammogram is used to confirm placement in the correct position.

Possible complications are similar to those of a biopsy. These include pain, bleeding, infection and inflammation.

What are the benefits of taking part?

Placing the Magseed a week before surgery will help make the day of surgery less busy and stressful for you.

Magseed is not externally visible after placement and will not restrict your daily activities

It may minimise your waiting time on the day of surgery

Your surgeon can plan the incision during surgery, which may allow for less tissue removal and can achieve better cosmetic results

What happens during surgery?

The Sentimag probe is used to detect the location of the Magseed within the breast, allowing your surgeon to plan the best path to the tumour. The Magseed then guides the surgeon to the tumour during surgery. Finally, once the tumour is removed an x-ray of the removed tissue including the Magseed will be taken to confirm removal of the Magseed and the targeted area.

Do I have to take part?

There is no requirement to take part in the evaluation of Magseed.

If you agree to take part in the evaluation we will ask that you sign a consent form.

We will ask you to fill out a short questionnaire regarding your experience.

You are free to withdraw at any time without giving a reason.

If you decide not to take part you do not need to give a reason and your standard of care will not be affected.

Contacts / Further information

Cambridge Breast Unit
Tel: 01223 217627

References / Sources of evidence

This content is not intended nor recommended as a substitute for medical advice, diagnosis or treatment.

Always seek the advice of a qualified physician regarding any medical questions or conditions.

©2020 Merit Medical Systems, Inc. All rights reserved.

National Breast Cancer website (opens in a new tab)

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Telephone +44 (0)1223 245151