Bioimpedance Spectroscopy Seems Better Than Tape Measure for Detecting Lymphedema Early

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Using bioimpedance spectroscopy to measure lymph fluid buildup seems better than using a tape measure to keep track of arm circumference for detecting lymphedema, according to early results from a study.

The research, “Interim analysis lymphedema ‘PREVENT’ trial,” was presented on May 2, 2019, at the American Society of Breast Surgeons annual meeting in Dallas.

What is lymphedema?

Lymphedema is a potential side effect of breast cancer surgery, radiation therapy, and sometimes chemotherapy that can appear in some people months or even years after treatment ends.

Lymph is a thin, clear fluid that circulates throughout the body to remove wastes, bacteria, and other substances from tissues. Edema is the buildup of excess fluid. So, lymphedema occurs when too much lymph collects in any area of the body. If lymphedema develops in people who’ve been treated for breast cancer, it usually occurs in the arm and hand, but sometimes it affects the breast, underarm, chest, trunk, and/or back.

Breast cancer surgery — especially when several lymph nodes are removed — and radiation can cut off or damage some of the nodes and vessels through which lymph moves. Over time, the flow of lymph can overwhelm the remaining pathways, resulting in a backup of fluid into the body’s tissues.

Although lymphedema can affect the breast, chest, and underarm areas, it’s more common in the arm or hand on the same side as the breast cancer surgery. Because early swelling in the arm can be hard to notice, treatment guidelines recommend taking baseline measurements before surgery and then at regular intervals afterwards.

“Lymphedema significantly lowers quality of life and consistently ranks as the number one fear of breast cancer survivors,” lead study author, Sheila Ridner, Ph.D., R.N., of Vanderbilt University School of Nursing, said in a statement.

What is bioimpedance spectroscopy?

Bioimpedance spectroscopy, also called BIS, is a newer non-invasive technique to measure the volume of fluid in various parts of the body. BIS involves passing an extremely low-strength electrical current through the area and measuring how the flow of the current is slowed by the fluid in the body. It’s important to know that BIS is not available everywhere.

How this study was done

This study, called the PREVENT trial, enrolled women who had been diagnosed with breast cancer before they had surgery. The women were randomly assigned to have a baseline arm measurement taken before surgery and then be monitored for lymphedema by having their arms measured with either:

  • BIS
  • a tape measure

After surgery, women diagnosed with stage 0 to stage III breast cancer who had at least one of the following continued in the study:

  • mastectomy
  • axillary lymph node surgery
  • sentinel lymph node surgery with more than six nodes removed
  • axillary lymph node radiation
  • taxane-based chemotherapy — taxanes include Taxol (chemical name: paclitaxel), Taxotere (chemical name: docetaxel), and Abraxane (chemical name: albumin-bound or nab-paclitaxel)

Women who had double mastectomy were not included in the study analysis.

Starting 90 days after surgery, the women’s arms were regularly assessed for lymphedema for at least 12 months.

If a woman’s arm measurement increased by 5% or more from the baseline measurement, she was considered to have subclinical lymphedema and prescribed a precisely fitted compression sleeve and chest gauntlet, which she wore for 12 hours daily for 28 days.

Subclinical means the lymphedema was causing no visible symptoms and couldn’t be detected unless the women’s baseline and later arm measurements were compared.

After the 28 days, the women’s arms were reevaluated. If the arm measurement increased by 10% or more, the woman was diagnosed with clinical lymphedema and was prescribed complex decongestive therapy. Complex decongestive therapy, also called complete decongestive therapy, is an intensive program that combines a number of treatment approaches, including bandaging, compression garments, manual lymphatic drainage, exercise, and self-care. Complex decongestive therapy is considered the gold standard of treatment for lymphedema that has progressed beyond stage 1 — meaning there is visible swelling without pitting (a temporary indentation that forms on the skin when pressed) and there may be evidence of fibrosis (scarring of soft tissue).

A total of 508 women were included in this early analysis. All the women had been followed for at least 12 months after surgery.

The women’s characteristics:

  • 77% were white
  • half were younger than 58.8 years and half were older
  • half the women had a BMI higher than 27.9 and half had a BMI that was lower
  • 44% also had heart problems
  • 56.7% were diagnosed with stage I breast cancer
  • 39.0% were diagnosed with stage II or stage III breast cancer

Overall, 109 women had their arm measurement increase by 5% or more and were considered to have subclinical lymphedema:

  • 68 women were being monitored with a tape measure
  • 41 women were being monitored with BIS

Of these women, 10 in the tape measure group and two in the BIS group then had their arm measurements increase by 10% or more compared to the baseline measurement and were diagnosed with clinical lymphedema and were prescribed complex decongestive therapy.

"Because it is thought that earlier identification of swelling in the limbs, coupled with a compression intervention, may reduce the risk of patients developing full-blown clinical lymphedema, clinicians are proposing to use a prospective surveillance model to follow breast cancer survivors post-surgery," Ridner said at a media briefing.

Although more women in the tape measure group were diagnosed with subclinical lymphedema and were prescribed compression garments, more also went on to have clinical lymphedema. Ridner explained that significant fluid accumulation is required for measurable increases in arm circumference. Also, a tape measure assessment includes fat, bone, soft tissue, and other fluids that may result from the trauma of cancer treatment, complicating interpretation. Tape measure assessment also leaves more room for human error. Ridner added that because BIS relies on electrical current to gauge fluid resistance between cells, it provides extremely specific and precise measurement.

Still, it’s important to know that the difference in the numbers of women diagnosed with clinical lymphedema was not statistically significant. This means that it could have been due to chance and not because of the difference in monitoring methods.

What this means for you

This and other small, early studies suggest that BIS may be a good way to proactively check for small changes in arm volume that may not be visible with a tape measure. Still, more research is needed before BIS can become the standard of care.

If you’ve been diagnosed with breast cancer and know that you’ll be having surgery, radiation, or chemotherapy, there are things you can do before treatment starts to reduce your risk of lymphedema, including scheduling an appointment with a medical professional who specializes in lymphedema management. A trained lymphedema therapist can take baseline measurements of your arm and hand, as well as assess the strength of your arm and upper body, and then create a tailored post-surgery exercise and rehabilitation plan for you.

For more information, visit the Breastcancer.org pages on Reducing Risk of Lymphedema and Lymphedema Flare-Ups.

To talk with others about lymphedema, join the Breastcancer.org Discussion Board forum Lymphedema.

Written by: Jamie DePolo, senior editor

Reviewed by: Brian Wojciechowski, M.D., medical adviser


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