Digital Phenotyping in Women Over 70 Years of Age Treated for Breast Cancer With Any Type of Treatment

GrannyFit is a prospective, national, multicenter, single-arm open-label study. It will include a total of 200 participants over the age of 70 years treated for de novo or recurrent (local or distant) BC. Participants will receive a Withing Steel activity tracker, which they will be asked to wear 24 h per day for 12 months. The principal assessments will be performed at baseline, at 6 months and at 12 months. The investigators will evaluate clinical (e.g. comorbidities), lifestyle, quality of life, fatigue, and physical activity parameters. All questionnaires will be completed on a REDCap form, via a secure internet link.

Inclusion Criteria: * Women over 70 years of age, * With histologically confirmed invasive breast cancer, * Regardless of histological subtype (hormone receptor positive (HR+), negative (HR-), with or without HER2 overexpression, or triple negative) * Treated with local (surgery, radiotherapy) or systemic (hormone therapy, monotherapy, anti HER2, chemotherapy: patient is eligible for inclusion up to one month after initial diagnosis or recurrence (local or distant) of breast cancer, * PS ≤ 2, * Willing and available to invest in the project for the duration of the study, * Using a personal smartphone or personal tablet compatible with the "Withings Health Mate" app (iOS 10/android 5.0 and later) and with an internet connection, * Affiliated with a social security plan, * Having dated and signed an informed consent, * Able to read, write and understand French. Exclusion Criteria: * Presence of disabling metastases, * Moderate to severe cognitive impairment, * Persons deprived of liberty or under guardianship, * Inability to undergo the medical follow-up of the trial for geographical, social or psychological reasons,