Patients with localized breast cancer undergo treatment that includes breast surgery, which always alters their body image, complemented by optional additional treatments depending on the specifics and severity of their disease. These treatments are multimodal and may include chemotherapy, radiotherapy, targeted anticancer treatments, and hormone therapy, followed by prolonged monitoring for at least 5 years. A recent study showed that the announcement of cancer and its treatments is a source of reactive anxiety for 47% of patients at the time of diagnosis, which can be associated with depression in 59% of cases before chemotherapy. Anxiety increases with the intensity of treatments and is higher when chemotherapy is administered, especially in younger patients (under 50 years old). The integrative multidisciplinary care available in treatment centers (psychologist, adapted physical activity, socio-aesthetician), combined with external support through associative networks (art therapy, music therapy, etc.), is crucial for improving quality of life and treatment side effects. Sophrology is one of these complementary therapies recommended by Association Francophone Des Soins Oncologiques De Support (French Association for Supportive Care in Oncology) within or outside the healthcare structure and is validated as supportive care. Its principle is to positively enhance patients' qualities and resources by altering states of consciousness, allowing individuals to find a balance between their thoughts, emotions, and behaviors. The three fundamental principles are to bring the body schema to a more lived reality, reinforce positive action, and develop objective reality. The mindfulness techniques used in sophrology include dynamic relaxation and sophronizations. Sophrology is based on the scientific principles of mindfulness meditation (developing attentional resources and body awareness by modulating brain waves). Studies have shown the benefits of mindfulness in managing stress, certain psychosomatic conditions, and chronic pain. Improvements in overall quality of life, stress symptoms, and sleep quality have been reported in the evaluation of a mindfulness meditation program for cancer patients. A trial demonstrated the beneficial effect of group mindfulness meditation on the anxiety of women who had undergone chemotherapy for breast cancer. Today, although sophrology is regularly used in medical care, no robust scientific study has evaluated its benefit in oncology. Institut National de la Santé et de la Recherche Médicale, together with Haute Autorité de la Santé, highlighted in its 2020 report on sophrology the significant need to scientifically assess the interest of sophrology in medical care. However, the use and accessibility of complementary therapies, including sophrology, are very unequal across France and depend on hospitals, geography, patient mobility, and sometimes the financial ability of patients to access paid complementary therapies. As a result, many anxious patients cannot access sophrology sessions at the desired time due to geographical, accessibility, human resource, and sometimes financial reasons (outside the hospital). The Morphée® device could help reduce these disparities and accessibility issues by allowing patients to perform a sophrology session at any time and place after receiving explanations from a healthcare professional.