Breast cancer and its treatment with radiotherapy may be associated with systemic inflammatory, hematological, cardiac, body composition, functional and quality-of-life alterations. Exercise has emerged as a non-pharmacological strategy with potential benefits during oncological treatment; however, further evidence is needed regarding the effects of supervised moderate-intensity interval aerobic exercise during radiotherapy. This randomized controlled trial aims to evaluate the effects of a supervised moderate-intensity interval aerobic exercise programme on systemic inflammatory and immune-derived hematological indices, cardiac biomarkers, body composition, muscle strength, lower-limb power, sleep quality and breast cancer-specific quality of life in women with breast cancer undergoing radiotherapy. Participants will be allocated to either an experimental group performing supervised moderate-intensity interval aerobic exercise during radiotherapy or to a control group receiving usual care without structured exercise during the study period. Outcomes will be assessed at baseline and after completion of the intervention period.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
40
Structured and supervised aerobic exercise intervention based on moderate-intensity interval training. The programme includes repeated aerobic exercise bouts interspersed with recovery periods. Exercise intensity is individually prescribed and adjusted according to baseline physiological assessment, including blood lactate response, perceived exertion and clinical tolerance. The intervention is delivered during the radiotherapy treatment period as an adjunct to standard oncological care.
Systemic Immune-Inflammation Index (SII)
Systemic Immune-Inflammation Index (SII) will be calculated from peripheral blood parameters obtained through standard hematological analysis using an automated analyzer. The index will be computed using the formula: platelet count × neutrophil count / lymphocyte count. Blood samples will be collected under standardized conditions after an overnight fast, with participants instructed to avoid vasoactive medication, caffeine, alcohol and tobacco prior to sampling. Post-intervention samples will be obtained at least 48 hours after the last exercise session to ensure assessment of chronic rather than acute responses. This composite index will be used to quantify changes in systemic inflammatory and immune status associated with the intervention.
Time frame: Baseline (pre-intervention) and immediately after intervention
Neutrophil-to-Lymphocyte Ratio (NLR)
Neutrophil-to-Lymphocyte Ratio (NLR) will be calculated from absolute neutrophil and lymphocyte counts obtained through peripheral blood analysis using an automated hematology analyzer. This index will be used as a marker of systemic inflammatory balance.
Time frame: Baseline (pre-intervention) and immediately after intervention
Platelet Count
Platelet count will be obtained from peripheral blood samples using standard hematological procedures and automated analysis, and will be used as a parameter of systemic inflammatory and hematological status.
Time frame: Baseline (pre-intervention) and immediately after intervention
Neutrophil Count
Absolute neutrophil count will be obtained from peripheral blood analysis using an automated hematology analyzer and will be used to assess innate immune response.
Time frame: Baseline (pre-intervention) and immediately after intervention
Lymphocyte Count
Absolute lymphocyte count will be obtained from peripheral blood analysis using an automated hematology analyzer and will be used to assess adaptive immune status.
Time frame: Baseline (pre-intervention) and immediately after intervention
NT-proBNP
N-terminal pro-B-type natriuretic peptide (NT-proBNP) will be quantified in venous blood samples (pg/ml) using standardized laboratory assays according to manufacturer instructions, as a biomarker of cardiac stress and subclinical cardiac involvement.
Time frame: Baseline (pre-intervention) and immediately after intervention
High-Sensitivity Troponin I
High-sensitivity troponin I (hs-TnI) will be measured in venous blood samples (ng/L) using validated high-sensitivity assays according to manufacturer protocols, as a biomarker of myocardial injury.
Time frame: Baseline (pre-intervention) and immediately after intervention
Body Weight
Body weight will be measured in kilograms using calibrated scales under standardized conditions, with participants in light clothing and barefoot.
Time frame: Baseline (pre-intervention) and immediately after intervention
Phase angle
Phase angle will be assessed using multifrequency octopolar bioelectrical impedance analysis (BIA) under standardized conditions, including fasting state and controlled hydration status, as an indicator of cellular integrity and body cell mass.
Time frame: Baseline (pre-intervention) and immediately after intervention
Fat Mass
Fat mass will be assessed using bioelectrical impedance analysis (BIA) following standardized pre-measurement conditions, including fasting and abstinence from exercise, caffeine and alcohol.
Time frame: Baseline (pre-intervention) and immediately after intervention
Muscle Mass
Muscle mass will be assessed using bioelectrical impedance analysis (BIA) under standardized conditions to evaluate skeletal muscle status.
Time frame: Baseline (pre-intervention) and immediately after intervention
Percentage Body Fat
Percentage body fat will be determined using bioelectrical impedance analysis (BIA).
Time frame: Baseline (pre-intervention) and immediately after intervention
Visceral fat area
Visceral fat area (VFA) will be estimated using bioelectrical impedance analysis as an indicator of central adiposity and cardiometabolic risk.
Time frame: Baseline (pre-intervention) and immediately after intervention
Relative Lower-Limb Power: Handgrip Strength
Right and left handgrip strength will be measured (kg) using a calibrated handheld dynamometer. Participants will perform three maximal voluntary contractions per hand following standardized procedures, with adequate rest between attempts. The highest reproducible value for each hand will be recorded.
Time frame: Baseline (pre-intervention) and immediately after intervention
Relative Lower-Limb Power (Chair Stand Test)
Relative lower-limb power will be assessed using the 30-second Chair Stand Test. Participants will perform as many full stands as possible from a standardized chair (≈43-45 cm height) within 30 seconds, with arms crossed over the chest. The number of repetitions will be recorded. A relative lower-limb power index will be derived from repetitions and body mass, expressed in W/kg equivalent units, providing an estimate of lower-limb functional performance normalized by body mass.
Time frame: Baseline (pre-intervention) and immediately after intervention
Breast Cancer-Specific Functional Quality of Life
Functional quality of life will be assessed using the functional scales of the EORTC QLQ-C30 and QLQ-BR45 questionnaires. Scores will be linearly transformed to a 0-100 scale, where higher scores indicate better functional status.
Time frame: Baseline (pre-intervention) and immediately after intervention
Breast Cancer-Specific Symptom Burden
Symptom burden will be assessed using the symptom scales of the EORTC QLQ-C30 and QLQ-BR45 questionnaires. Scores will be transformed to a 0-100 scale, where higher scores indicate greater symptom severity.
Time frame: Baseline (pre-intervention) and immediately after intervention
Sleep Quality (PSQI)
Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). The global score will be used for analysis, where higher scores indicate poorer sleep quality.
Time frame: Baseline (pre-intervention) and immediately after intervention
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