Research Update — March 2021

Hasenoehrl, T., Palma, S., Ramazanova, D., et al.
Resistance exercise and breast cancer-related lymphedema- a systematic review update and meta-analysis
Supportive Care in Cancer (2020), 28, 3593-3603

ABSTRACT

Background: The purpose of this systematic review update and meta-analysis was to analyze resistance exercise (RE) intervention trials in breast cancer survivors (BCS), regarding their effect on breast cancer-related lymphedema (BCRL) status and upper and lower extremity strength.

Methods: Systematic literature search was conducted using PubMed, MEDLINE, and Embase databases. Any exercise intervention studies (randomized controlled and uncontrolled) which assessed the effects of RE on BCRL in BCS in at least one intervention group published between 1966 and January 31^st, 2020, were included. Included articles were analyzed regarding their level of evidence and their methodological quality using respective tools for randomized and non-randomized trials of the Cochrane collaboration. Meta-analysis for bioimpedance spectroscopy (BIS) values as well as upper and lower extremity strength was conducted.

Results: Altogether, 29 studies were included in the systematic review. Results of six of these studies with twelve RE intervention groups could be pooled for meta-analysis of the BCRL. A significant reduction of BCRL after RE was seen in BIS values (95% CI − 1.10 [− 2.19, − 0.01] L-Dex score). Furthermore, strength results of these six studies could be pooled and meta-analysis showed significant improvements of muscular strength in the upper and lower extremities (95% CI 8.96 [3.42, 14.51] kg and 95% CI 23.42 [11.95, 34.88] kg, respectively).

Conclusion: RE does not have a systematic negative effect on BCRL and, on the contrary, potentially decreases it.

INSPIREHEALTH’S INTERPRETATION

Lymphedema is a potential long-term side effect of breast cancer treatments and can be developed by close to 20% of breast cancer patients. Risk factors include the removal of lymph nodes during surgery and radiation to an area containing lymph nodes. These treatments can potentially decrease the ability of the local lymph nodes to perform their function of fluid filtration, thereby creating an excess accumulation of lymphatic fluid which can lead to localized swelling. This can be experienced as pain, heaviness, tightness, decreased range of motion, affected motor skills, impaired daily function, and decreased quality of life. Most sources would consider lymphedema to be an incurable condition and, therefore, a need exists to focus on education and management techniques.

Up until the early 2000s, those at risk of lymphedema or who had lymphedema were advised to refrain from “vigorous, repetitive, or excessive upper body exercise” out of fear that these activities could lead to or exacerbate lymphedema. These myths have now been repetitively debunked by researchers worldwide, including prominent researchers from British Columbia. Regular exercise has been shown to have no negative effect on lymphedema and in many cases, even improve it.

This research paper aimed to review and analyze the existing research related to resistance (strength) exercise and its impact on lymphedema among breast cancer survivors. The authors analyzed data from 29 studies as well as performed additional statistical analyses of the data (in form of a meta-analysis). The studies included measured lymphedema through bioimpedance spectroscopy (a non-invasive way to measure total body water and fluid levels) as well as upper and lower extremity strength.

While the resistance exercise prescription varied slightly between studies, most studies included between two to three sessions per week of exercise, which incorporated a progression of sets and repetitions as well as adaptations to the load lifted. Each study included a minimum of six exercises, focusing on the major muscle groups of both the upper and lower body. Study duration also varied between 2 to 50 weeks.

The results of the study showed a statistically significant reduction in lymphedema, as well as significant increases in both upper and lower body strength. The authors summarize the results by stating that this data supports the current research, in that resistance exercise does not negatively impact lymphedema and can, in fact, improve it.

If you have lymphedema or are at risk for developing it, it is always recommended to work with a trained exercise professional to determine an exercise program to support you and your needs. InspireHealth offers individualized and group exercise support as well as educational sessions related to lymphedema.