This single-centre, two-arm, parallel-group, assessor-blinded pilot randomised controlled trial was conducted at the Hospital Universitario Príncipe de Asturias in Alcalá de Henares, Spain. Physiotherapy interventions were delivered at the University of Alcalá.
Participants were allocated using a computer-generated randomisation sequence, with allocation concealment maintained through sequentially numbered, opaque, sealed envelopes. Outcome assessments were conducted by researchers who remained unaware of group allocation.
The physiotherapy intervention began three months after completion of radiotherapy and lasted four weeks. Participants attended four individual, face-to-face physiotherapy sessions, scheduled once weekly. The programme included patient education and individually prescribed aerobic and resistance exercise, performed independently at home or in community settings. Additional respiratory training was performed using incentive spirometry and positive expiratory pressure devices, following individual instruction and supervision.
Exercise and respiratory training were prescribed according to each participant's physical condition and tolerance. Physical activity was monitored using wrist-worn activity trackers, while adherence to the intervention was reviewed during the weekly sessions.
Assessments were conducted at five time points: before breast cancer surgery, after surgery, three months after radiotherapy (pre-intervention), four months after radiotherapy (post-intervention), and six months after radiotherapy (follow-up).
Feasibility was assessed through recruitment, retention, attendance, and adherence to the prescribed activities. Safety was evaluated by recording adverse events during the intervention period. Clinical outcomes were analysed exploratorily to estimate changes over time and between-group differences, accounting for age, body mass index, and the number of radiotherapy sessions.
