Muscle Oxygen Saturation and Functional Capacity in Breast Cancer Survivors

Analysis of Muscle Oxygen Saturation and Functional Variables During Physical Performance Tests in Breast Cancer Survivors

This cross-sectional observational study aims to assess muscle oxygen saturation (SmO2) in the intercostal, quadriceps, and triceps surae muscles using near-infrared spectroscopy (NIRS) during functional exercise tests in breast cancer survivors. Participants will be grouped based on their previous cancer treatment: hormonal therapy only or hormonal therapy combined with chemotherapy. Functional performance will be evaluated through the 6-Minute Walk Test, 30-Second Sit-to-Stand Test, and a submaximal treadmill test. The study will analyze differences in muscle oxygenation and performance between groups and explore associations with other functional and clinical parameters.

This study focuses on evaluating muscle oxygen saturation and physical performance in women who have survived breast cancer. Cancer treatments such as chemotherapy and hormonal therapy can lead to systemic effects, including muscular deconditioning, fatigue, and reduced cardiorespiratory capacity. Near-infrared spectroscopy (NIRS) offers a non-invasive means of assessing SmO2 in real-time, providing insight into oxygen delivery and utilization during exercise.

Participants will undergo three functional tests: the 6-Minute Walk Test, the 30-Second Sit-to-Stand Test, and a submaximal treadmill test. Muscle oxygenation will be measured in three key muscle groups before, during, and after each task. Additional outcomes include functional test performance, respiratory strength, pulmonary function, fatigue perception, and quality of life questionnaires. This study will explore whether prior cancer treatment protocols affect muscle oxygenation and physical function differently, and may inform future rehabilitation strategies tailored to breast cancer survivors.

Inclusion Criteria:

• Women aged 30 to 70 years
• Clinical history of breast cancer treatment (at least 6 months prior)
• Completed primary cancer treatment
• Ability to perform physical tests
• Signed informed consent

Exclusion Criteria:

• Recurrence or metastasis
• Severe cardiopulmonary or musculoskeletal disease
• Neurological or cognitive limitations
• Ongoing oncological treatment