Does a Resistance Training Program Affect Between-arms Volume Difference and Shoulder-arm Disabilities in Female Breast Cancer Survivors? The Role of Surgery Type and Treatments. Secondary Outcomes of the EFICAN Trial

Objective: The aims were (i) to assess the effects of a 12-week resistance training program on between-arms volume difference and shoulder-arm disabilities in breast cancer survivors and (ii) to evaluate whether the main risk factors for developing cancer-related lymphedema and shoulderarm disabilities were associated with the effects of the training program. Participants: 60 female breast cancer survivors participated. Eligibility criteria: to be a breast cancer survivor, and to have completed surgery, chemotherapy, and/or radiotherapy up to 10 years before recruitment. Exclusion criteria: metastatic breast cancer, a breast reconstruction intervention planned within 6 months, any absolute contraindication for exercise, to perform more than 300 minutes/week of structured exercise. Interventions: Participants were randomized to an exercise group (12-week resistance training program) or a control group. Main Outcome Measures: Between-arms volume difference, shoulder-arm disabilities, and upper-limb muscular strength were evaluated at baseline and at week 12. Treatment-related information was registered from medical history. Results: No between-group differences were observed on between-arms volume difference (1.207; 95% CI -0.964, 3.377; P=.270) or shoulderarm disabilities (2.070; 95% CI -4.362, 8.501; P=.521) after the training program. Likewise, there was no association of surgery type, presence of lymph node resection, chemotherapy, radiotherapy, and hormone therapy with the changes in between-arms volume and perceived shoulder-arm disabilities after the intervention. However, a higher increase in upper limb muscular strength was associated with a reduced shoulder -arm disabilities (-0.429; P =.020) in the exercise group. Conclusions: The findings suggest that resistance training does not affect between -arms volume difference and shoulder -arm disabilities in female breast cancer survivors. The main risk factors for developing lymphedema were not associated with the effects of the intervention, although a higher increase in upper -limb muscular strength was associated with reduced shoulder -arm disabilities. Archives of Physical Medicine and Rehabilitation 2024;105:647 -54 (c) 2023 by the American Congress of Rehabilitation Medicine. Published by Elsevier Inc. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)