The primary objective of the study is to evaluate the effects of exercise on physical function, physical fitness, and body composition, with the main components including muscular strength, cardiorespiratory fitness, muscle mass, fat mass, and fat-free mass. The secondary objectives are to examine exercise adherence and the effects of exercise on health-related quality of life (HRQoL), cancer-related fatigue, and sleep quality. Additionally, the feasibility and safety of the exercise program will be assessed.
Historically, cancer patients, especially those in more advanced stages of the disease, were advised to maintain rest due to concerns about complications associated with tumor progression and the adverse effects of treatment. However, evidence accumulated over the past decades has demonstrated that physical inactivity may accelerate functional decline, reduce physical capacity, and impair quality of life in individuals with cancer. In this context, physical exercise has come to be recognized as an important strategy in cancer care. The regular practice of aerobic and resistance exercises has been associated with the reduction of treatment-related side effects, the preservation of physical function, and improvements in quality of life in different populations of cancer patients. In women with breast cancer, studies have shown that physical exercise can contribute to improvements in cardiorespiratory capacity, muscular strength, physical function, and quality of life, as well as help reduce cancer-related fatigue. However, most of the available evidence focuses on patients in the early stages of the disease or after primary treatment. In the case of women with metastatic breast cancer, scientific knowledge remains limited. Despite therapeutic advances that have increased survival in this population, these patients frequently experience functional decline, severe fatigue, loss of muscle mass and strength, and reduced quality of life. Furthermore, physical exercise is still rarely incorporated into the care of these patients, often due to uncertainties regarding the safety and effectiveness of such interventions. Although emerging evidence suggests that physical exercise may be safe and feasible for patients with metastatic disease, studies investigating structured and long-term exercise interventions in this population remain scarce. Therefore, further research is necessary to expand understanding of the effects of physical exercise in women with metastatic breast cancer, particularly focusing on physical function, physical fitness, body composition, and quality of life.
Study Type
INTERVENTIONAL
The multicomponent exercise intervention included a 10-minute warm-up consisting of balance, coordination, and stretching exercises. The main component was resistance training targeting the major muscle groups of the upper and lower body to improve strength and muscle mass. Six to eight exercises were performed using body weight, resistance bands, and dumbbells. Training progression was achieved by increasing load, repetitions, and/or sets, guided by the Borg 0-10 rating of perceived exertion scale, when health status allowed. The aerobic component consisted of walking, progressing to beginner-level running using short running intervals (50-100 m) interspersed with walking until longer continuous distances were achieved. Heart rate was monitored throughout the aerobic session.
Universidade Estadual de Londrina, Londrina
Londrina, Paraná, Brazil
Cardiorespiratory endurance and functional capacity
6MWT was performed as a parameter of cardiorespiratory endurance and functional capacity. Participants were instructed to walk back and forth along a flat, straight 25m corridor for six minutes, covering as much distance as possible at a self-selected pace. The total distance walked (in meters) was recorded as the primary outcome.
Time frame: Baseline and week 24 (post exercise intervention)
Lower-limb muscle strength
Lower-limb muscle strength was assessed using the five-repetition sit-to-stand test (5xSTS), according to the European Working Group on Sarcopenia in Older People (EWGSOP2)¹. Participants were instructed to stand up and sit down five times as quickly as possible, with their arms crossed over the chest. The total time to complete the test was recorded in seconds (s) and used as an indicator of muscle strength. All assessments were performed by a trained evaluator
Time frame: Baseline and week 24 (post exercise intervention)
Handgrip strength
Muscle strength was assessed using a handgrip dynamometer (SH5001, Saehan Grip, South Korea). Participants performed three maximal voluntary contractions with each hand in an alternating sequence, with a one-minute rest interval between trials. The highest value (kg) achieved was used for analysis. All measurements wer
Time frame: Baseline and week 24 (post exercise intervention)
Body composition
Body composition was assessed using tetrapolar bioelectrical impedance analysis (BIA) with the Analyxzer device. All assessments followed the manufacturer's standard protocols and were performed by a trained evaluator to ensure accuracy and reproducibility. Data analysis was conducted using the device-specific software. The following variables were obtained: total and appendicular fat-free mass, as well as fat mass. Results were expressed in absolute (kg) and relative (%) values.
Time frame: Baseline and week 24 (post exercise intervention)
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Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
78
Health-related quality of life
Health-related quality of life (HRQOL) was assessed using the Portuguese language version of the EORTC QLQ-C30 \[Aaronson et al. 1993\]. The EORTC QLQ-C30 is a 30-item questionnaire comprising five functional scales (physical, role, emotional, cognitive, and social functioning), three symptom scales (fatigue, nausea and vomiting, and pain), and six single-item symptom measures (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). Scores for both instruments range from 0 to 100, with higher scores indicating greater symptom burden. The exception is the functional scales of the EORTC QLQ-C30, for which higher scores reflect better functional status.
Time frame: Baseline and week 24 (post exercise intervention)
Fatigue
Fatigue was assessed using the Portuguese language version of the EORTC QLQ-FA12 \[Weis et al. 2017\]. The EORTC QLQ-FA12 is a 12-item questionnaire that assesses multiple dimensions of fatigue, including physical, emotional, cognitive, interference with daily activities, and social sequelae.
Time frame: Baseline and week 24 (post exercise intervention)