Bioimpedance spectroscopy device helps with early detection of unilateral lymphoedema after breast cancer

Medtech Innovation Briefing outlines potential use for L-Dex U40 in diagnosing and monitoring breast cancer treatment

  • The L-Dex U400 is used for early detection of unilateral lymphoedema in the limbs after treatment for breast cancer
  • It uses bioimpedance spectroscopy to measure fluid status, aiming to detect lymphoedema earlier
  • The intended place in therapy would be in diagnosing or monitoring lymphoedema related to breast cancer treatment
  • Medical Innovation Briefing includes results of three UK and US clinical studies which show that L-Dex U400 is less effective than comparators in diagnosing lymphoedema, but potentially helps detect subclinical lymphoedema in people who have had treatment for breast cancer
  • The cost is £7,500 per unit

The L Dex U400

A new device uses bioimpedance spectroscopy to detect unilateral lymphoedema in the limbs after treatment for breast cancer that has removed or damaged the lymph nodes.

The L Dex U400, manufactured by Impedimed, is the subject of the latest Medtech innovation Briefing from the National Institute for Health and Care Excellence (NICE).

In bioimpedance spectroscopy, a small electrical current is passed through the affected limb and the resistance to the current is compared with the unaffected limb.

The resistance is used to calculate the total water content in the body, which can be used to detect lymphoedema, a build-up of lymphatic fluid in the body, particularly in the limbs, which causes swelling and enlargement.

A small, portable desktop system with a built-in display screen, the L-Dex U400 shows results as an L Dex ratio. The accumulation of extracellular fluid in the limb causes the L Dex ratio value to increase.

Other, traditional, methods for diagnosing lymphoedema, such as water displacement and tape measurement, are not able to distinguish between lymphatic fluid and the healthy tissues of the body. These methods can, therefore, be inaccurate, especially if there are changes to the body tissues, such as weight loss or gain.

The L Dex U400 uses bioimpedance spectroscopy, which can specifically measure extracellular fluid. This is designed to enable earlier detection of lymphoedema.

This will be of particular use in diagnosing lymphoedema in the limbs after treatment for breast cancer, a common problem affecting one in five sufferers.

Currently, the most-commonly-used method of lymphoedema detection in current NHS practice is periodic measurement of limb circumference using a tape measure, combined with a clinical assessment of the patient's skin and their mobility.

It is intended that the L Dex U400 would be used in secondary care to detect and monitor lymphoedema in people who have had chemotherapy, radiotherapy or surgery for breast cancer. It would typically be used by a trained nurse or physiotherapist as a part of routine screening.

The capital cost of the L Dex U400 is £7,500 per unit and it has a five year lifespan with no maintenance costs, and no calibration is needed.

For each patient, three single-use electrodes are used at a total cost of £3.75 per patient.

The Medtech Innovation Briefing outlines the findings of three trials in the UK and US using the L-Dex U400. They show that the technology is less effective than comparators in diagnosing lymphoedema, but potentially helps detect subclinical lymphoedema in people who have had treatment for breast cancer.

But it warns that uncertainties remain as the evidence base is still developing.

NICE Medtech Innovation Briefings aim to support NHS and social care commissioners and staff who are considering using new medical devices and other medical or diagnostic technologies. The information provided includes a description of the technology, how it’s used, and its potential role in the treatment pathway.

They also include a review of relevant published evidence and the likely costs of using the technology, but they are not NICE guidance and do not make any recommendations on the value of using the technologies. Whether or not to use the products described is entirely the choice of local staff.

However, the briefings will help to avoid the need for organisations to produce similar information, so saving staff time, effort and resources.

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