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A secondary analysis of data from the trial provided additional insight into risk factors for breast cancer-related lymphedema and has implications for clinical practice, researchers said.

John Boyages, MD, PhD, of Icon Cancer Center and Macquarie University in Australia, and colleagues examined the risk for lymphedema in participants of PREVENT by the type of treatment they received.

As the investigators noted in , the extent of axillary treatment was a significant risk factor. The rates of subclinical breast cancer-related lymphedema (sBCRL) were as follows:

• 20.3% for sentinel node biopsy (SNB)

• 21.1% for SNB+ regional node irradiation (RNI)

• 28.6% for axillary lymph node dissection (ALND)

• 50.6% for ALND + RNI

Patients who developed subclinical lymphedema initiated a 4-week intervention with a compression sleeve and gauntlet. Risk for progression to chronic breast cancer–related lymphedema (cBCRL) after the intervention was approximately 2% in the SNB and SNB+RNI groups. The risk increased to 8.6% in the ALND group and nearly 14% in the ALND+RNI group.

Boyages, who is now also at Icon Cancer Centre discussed the implications of the findings in the following interview.

Why did you decide to conduct this additional analysis of PREVENT?

Boyages: We really wanted to explore and understand the risk factors for cBCRL further based on the extent of axillary treatment. The extent of axillary surgery (SNB vs dissection) and radiation treatment to the axilla and other regional nodes are well known to be the key risk factors for lymphedema. The PREVENT trial provided a unique opportunity to assess the impact of early compression sleeve intervention after the detection of sBCRL by bioimpedance spectroscopy (BIS) (defined as ≥6.5 units of change from baseline measurement) or tape measurement (TM) (defined as a volume change of ≥5<10%) on cBCRL rates.

PREVENT differed from other studies as it looked at a large cohort of over 1,000 patients for 3 years, exploring the early detection of sBCRL using the traditional tape measure, causing a change in circumference versus a BIS technique looking for extracellular fluid.

In addition, all patients with sBCRL had active intervention using 4 weeks of a compression garment. This secondary analysis aimed to identify specific patient and treatment risk factors associated with axillary treatment, informing a more nuanced understanding of factors contributing to the development of cBCRL.

How should your findings affect clinical practice?

Boyages: Our findings have crucial implications for clinical practice. The study revealed that the extent of axillary treatment is a significant risk factor for cBCRL. Factors such as increasing BMI [body mass index], rural residence, supraclavicular fossa (SCF) radiation, and taxane chemotherapy also increased risk. We developed a where crude rates of chronic lymphedema were documented as low (≤5%, green), intermediate (>5%-10%, orange), or high (>10%, red) for easy reference by clinicians.

This information underscores the importance of tailoring lymphedema screening and intervention programs based on individual patient characteristics and treatment plans. Many clinicians quote the average risk of developing cBCRL as 20%, but understanding the actual risk for a particular patient may reduce stress mainly if the risk is very low or by introducing a more proactive screening program.

Specifically, incorporating BIS for screening, as opposed to TM, was associated with significantly lower cBCRL rates by almost 40%, suggesting that the choice of screening method matters.

Our proposed risk-based lymphedema screening and intervention program, outlined in provides a practical guide for clinicians to identify and address cBCRL risk factors in a personalized manner. Risks may also be used to tailor treatment strategies. For example, if a patient has one nodal micrometastasis after a SNB, is overweight, and has had taxanes, radiation could be de-escalated with treatment to levels 1 and 2 of the axilla and the internal mammary chain without treatment to the SCF.

Please tell us more about the pragmatic screening and prevention program you have proposed.

Boyages: The pragmatic screening and prevention program proposed in our study is designed to respond to the specific risk factors associated with cBCRL. The program categorizes patients into low-, intermediate-, and high-risk groups based on various factors, including axillary treatment, BMI, and radiation therapy. Screening frequency and intervention intensity increase as the risk of cBCRL rises.

This risk-stratified approach allows for a more tailored and resource-efficient implementation of lymphedema screening and early intervention. For example, for patients with normal or low BMI treated with a sentinel node biopsy only, with only one to two nodes dissected, and without axillary or SCF radiation, the 3-year risk of cBCRL was 3.3%. Patients who were overweight or obese treated with axillary dissection without radiation had a cBCRL risk of 30-35%.

Including BIS as a screening tool, with its demonstrated effectiveness in reducing cBCRL rates, further enhances the program's precision and potential impact on patient outcomes. Using the new stand-up SOZO device, an L-Dex score can be obtained in less than 1 minute and is associated with fewer false positives than TM.

In addition, subclinical lymphedema is much easier to treat and potentially reversible compared with cBCRL. It's very similar to early detection using mammographic screening. Treating breast cancer when the doctor or patient can feel a lump is always more complicated than an impalpable screen-detected breast lesion.

What do you advise about educating patients on this topic?

Boyages: Patient education on lymphedema is paramount for optimal outcomes. Given the identified risk factors, providing evidence-based risk-reduction education is crucial. Patients should be informed about the importance of regular lymphatic screening, especially if they fall into higher-risk categories, such as being overweight or obese, receiving specific radiation treatments, or undergoing axillary dissection.

Education should empower patients to recognize symptoms and adopt appropriate arm care and lifestyle practices. Moreover, our proposed screening and intervention pathways, outlined in , can guide healthcare providers and patients, facilitating shared decision-making and enhancing adherence to personalized care plans, which include arm edema, breast edema, scar management, and shoulder function.

Is there anything else you want to make sure oncologists understand about your research or this topic?

Boyages: In March 2023, the National Cancer Control Network updated its survivorship guidelines to include the fact "that early detection/diagnosis and early referral are key for optimal lymphedema management because stages 0 and I are reversible, whereas stages II and III are less responsive to treatment. Therefore, survivors at risk for lymphedema should be regularly screened for lymphedema by symptom assessment, clinical examination, and, if available, BIS." Multidisciplinary teams must work out how to integrate lymphatic screening into their clinical setting.

Our study underscores the need for ongoing education and monitoring, especially for high-risk patient groups. It encourages oncologists to consider the proposed screening and intervention program as a practical guide in their clinical decision-making processes. Figure 3 gives specific screening options (including TM, perometry, and BIS) and proposed interventions if subclinical or chronic lymphedema is diagnosed.

Read the study here.