The technology

Magseed (Endomag) is a marker that commonly used for localising impalpable breast lesions. It is a small single-use metal device (seed) designed to accurately mark the site of a breast cancer lesion for surgical removal. Magseed is 5 mm long and made of surgical grade stainless steel. Magseed has a low nickel content and is non-radioactive.

Magseed is put into a person with a needle under local anaesthetic and ultrasound or stereotactic X-ray guidance. It is to help guide surgeons during a breast lumpectomy for impalpable breast cancer. At the time of surgery, Magseed's location is detected with the Sentimag probe (a magnetic sensing system). This sensing machine makes sounds of different pitches and gives a reading to let surgeons know how close they are to Magseed. The seed is then removed along with the tumour. Magseed can be implanted any time before the surgical procedure. The company and 1 expert also noted the use of Magseed to localise axillary lymph nodes in people who are having neoadjuvant chemotherapy in order to de-escalate surgical management of the axilla.

Complications may happen at any time during or after the procedure. Possible complications of Magseed may include hematoma, haemorrhage, infection, adjacent tissue injury, pneumothorax, allergic reaction and pain. It is not intended for use in the central nervous system, circulatory system, heart, eyes or brain. The device should not be placed in a tissue site with clinical evidence of infection.


Magseed is a localisation technique with no need for a wire. The company states that Magseed allows precise and less invasive implantation to locate cancer lesions. The company also notes that Magseed could be used for marking lymph nodes where wires could not be applied.

Wire guided localisation is standard practice for the removal of breast lesions. Wire guided localised breast surgery includes the insertion of a small wire into the breast, which guides the surgeon to the tissue in the breast. The wire is inserted by a radiologist or physician a few hours before the planned surgical removal of the tissue. They use X-ray or mammography to ensure the correct placement.

People felt less anxiety in the Magseed procedure compared with wire guided localisation (Micha et al. 2020). Experts thought the use of Magseed improved patient experience because of reduced pain and anxiety.

Current care pathway

There is an increasing trend towards breast conservation in the treatment of breast cancer. It is essential that impalpable lesions detected either on mammography or by ultrasound are accurately localised before an operation to allow them to be successfully removed in the first operation. The Association of Breast Surgery's best practise guidelines for surgeons in breast cancer screening state that localisation for impalpable lesions is needed for breast surgery, and placement of marker wires under X-ray or ultrasound guidance is the most common method. Radio-guided occult lesion localisation is also a recognised method of localisation used in a number of screening services. Any new localisation method should have an approved research trial or approved audit of practice showing equivalent results to recognised techniques before routine implementation.

Population, setting and intended user

Magseed is intended to be used as a marker to be placed in soft tissue and to be surgically removed within the target tissue after its placement. The marker that is placed into the person with impalpable breast cancer, when used with Sentimag, can help guide surgeons during a breast lumpectomy. It is also used for targeted axillary dissection procedures. It is a single-use marker. A clinical expert suggested that it is used for impalpable breast biopsy.

Magseed can be injected into the breast by the radiologists or an advanced radiology practitioner under either ultrasound or X-ray guidance before a breast cancer operation. There are some hospitals where Magseed is inserted by the surgeon. On the day of surgery, the surgeon uses a handheld probe called Sentimag to find the Magseed location in the breast.


Technology costs

A box of 10 Magseeds costs £2,500 and the reusable Sentimag probe costs £25,000 per unit. The company states that Magseed is single use and the Sentimag unit can last for over 5 years. The cost for using Magseed is £250 per Magseed (when the cost of the Sentimag unit has been deducted). The cost of insertion of marker such as Magseed for localisation of breast lesion as an outpatient procedure is £277 (NHS tariff 2019/20).

Costs of standard care

The company states that the costs for wire used in wire guided localisation procedure is estimated at £35 to £50. The cost of insertion of wire for localisation of breast lesion is £277 as an outpatient procedure or an elective procedure (NHS tariff 2019/20).

Resource consequences

Magseed is used in 42 NHS trusts. The main barrier to implementing a Magseed localisation procedure is the cost of the individual Magseed and the Sentimag probe. The company indicated that the cost of technology itself costs more compared with the standard wire guided procedure for breast cancer. But, it could be resource releasing if it improves efficiency in clinics (that is, clinic scheduling and capacity), and re-excision rates.

A service evaluation compared the cost of 226 traditional wire guided wide local excisions with the cost of 90 traditional guided wide local excisions plus 106 Magseed-guided excisions. The results suggested a saving of £34,457 with 48% fewer further operations after the introduction of Magseed (Lake et al. 2020). Using the technology in the NHS would not need any change to facilities or infrastructure. The company provides training and support for radiologists, surgeons and theatre staff. There are also online training videos that can be used. All training is free of charge.