Digital Phenotyping in Young Breast Cancer Patients Treated With Neoadjuvant Chemotherapy

Inclusion criteria : * female * ≥ 18 years old and \<70 years old * histologically confirmed BC, whatever the histological subtype (hormone receptor positive (RH+), negative (RH-), with (HER2+) overexpression or without (HER2-) HER2 overexpression, or triple negative) * planned NAC (up to the day of the first neoadjuvant chemotherapy treatment) * Eastern Cooperative Oncology Group Performance status ≤2 * willing to participate for the entire duration of the study * ability to use a compatible smartphone or Tablet PC to download the application Withings Health Mate (from iOS 10 and Android 5.0 or above) * Internet access * valid health insurance * able to read, write and understand French Exclusion criteria : * presence of metastases * Presence of bilateral breast cancer * a history of cancer other than basal cell skin lesions and cervical dysplasia * pregnancy, likelihood of pregnancy, or breastfeeding * impossibility of follow-up throughout the study for medical, social, family, geographic or psychological reasons * deprived of liberty through a judicial or administrative decision.