Resistance exercise and breast cancer-related lymphedema-a systematic review update and meta-analysis

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 utilizing PubMed, MEDLINE, and Embase databases. Any exercise intervention studies-both randomized controlled and uncontrolled-which assessed the effects of RE on BCRL in BCS in at least one intervention group published between 1966 and 31st January 2020 were included. Included articles were analyzed regarding their level of evidence and their methodological quality using respective tools for randomized and nonrandomized 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 studies with altogether 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 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.