Physical activity level and age contribute to functioning problems in patients with breast cancer-related lymphedema: a multicentre cross-sectional study.

Breast cancer survivors face a high risk of developing breast cancer-related lymphedema (BCRL). Besides physical symptoms such as swelling, BCRL can have a psychosocial impact and lead to problems in daily functioning. Understanding contributing variables to problems in functioning yields possibilities to improve treatment modalities and consequently patients' quality of life. Therefore, the aim of this study was to explore the association between patient-, lymphedema-, and cancer treatment-related variables with problems in functioning in patients with BCRL. A cross-sectional study was performed in 185 patients with BCRL. Problems in daily functioning (dependent variable) were evaluated with the Lymph-ICF-UL questionnaire. Following independent variables were analysed by bi-variate and multivariable analyses, including a stepwise regression analysis: patient-related variables (age, BMI, physical activity level, education), lymphedema-related variables (excessive arm volume, duration of lymphedema, total pitting score, presence of hand edema, hardness of the tissue, lymphedema stage), and cancer treatment-related variables (type of surgery, surgery at the dominant side, radiotherapy, chemotherapy, hormone therapy, immunotherapy, TNM-classification). The Lymph-ICF-UL mean total score was 38% (± 21), representing a moderate amount of problems in general functioning. Multivariable regression analyses revealed that lower physical activity level and lower age are contributing factors to more problems in daily functioning. Stepwise regression analysis indicated that up to 8% of the variance in problems in functioning could be explained by physical activity level and age of patients with BCRL. Especially patients with low physical activity level and younger patients experience more problems in functioning. For the determination of certain causal interactions, future longitudinal studies including other independent variables that might explain a higher amount of problems in functioning in this population, are warranted. The study makes part of a double-blind, multi-center, randomized controlled trial (EFforT-BCRL trial), which is registered in clinicaltrials.gov (NCT02609724). CME reference S58689, EudraCT Number 2015-004822-33.