Breast cancer is the most common cancer worldwide, with over 2.2 million new cases diagnosed in 2020. Treatments such as chemotherapy often lead to a reduced exercise capacity, mainly due to cardiovascular and neuromuscular dysfunctions. This decline appears to be primarily caused by increased central fatigue, while peripheral fatigue remains unchanged. This imbalance suggests a hyperactivation of type III-IV afferent nerve fibers, which are involved in the metaboreflex-a mechanism that significantly influences cardiovascular responses during exercise. Two non-invasive methods, post-exercise circulatory occlusion (PECO) and passive leg movement (PLM), will be used to assess this hyperactivity in patients. Additionally, baroreflex function-crucial for regulating blood pressure-will be evaluated using a direct method to determine its sensitivity and reactivity. By comparing patients with healthy controls under submaximal stimuli, this study aims to better understand chemotherapy-induced cardiovascular dysfunctions. Ultimately, the goal is to design personalized exercise programs to restore cardiovascular function and reduce treatment-related side effects.
Stage I to III breast cancer
Having completed (neo)adjuvant chemotherapy treatment less than three weeks ago
History of cancer
Any known chronic pathology
Protected minor or adult
Psychiatric, musculoskeletal or neurological problems
Parallel
Test of neuromuscular fatigue and associated hemodynamic responses
Other interventionBaseline measurements of neuromuscular function and hemodynamic responses will be performed. Baroreflex sensitivity will be assessed using a neck collar applying positive and negative pressures to stimulate the carotid baroreceptors, thereby modulating baroreflex activity in a dose-dependent manner. Mechanoreflex activation will then be evaluated using the passive leg movement (PLM) technique. After the PLM, participants will perform four fatigue tasks, each followed by 2 minutes of post-exercise circulatory occlusion (PECO). Tasks involve isometric quadriceps contractions at 20% of maximal voluntary contraction (MVC) during 1 min (block 1), 2 min (blocks 2 and 3) and until failure (block4). Neuromuscular function will be assessed through MVC changes and quadriceps twitch responses. Mean arterial pressure (MAP) will be recorded continuously. Metaboreflex activity will be determined by plotting post-PECO changes in peripheral fatigue against the change in MAP during PECO phases.
Characterize the metaboreflex in breast cancer patients at the end of chemotherapy treatment
Significant difference in mean arterial pressure, in response to a submaximal exercise, at rest and during exercise, between the two groups (patients and controls)
Characterize the baroreflex in breast cancer patients at the end of chemotherapy treatment.
Significant difference in mean arterial pressure, in response to a given stimulation of the carotid baroreceptors, at rest and during exercise, between the two groups (patients and controls)
Characterize the mechanoreflex in breast cancer patients at the end of chemotherapy treatment.
Significant difference in mean arterial pressure, in response to passive leg movement, between the two groups (patients and controls)
Compare heart rate reponses to submaximal exercise between the two groups
Significant difference in heart rate between the two groups (patients and controls)
Compare stroke volume responses to submaximal exercise between the two groups
Significant difference in stroke volume between the two groups (patients and controls)
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