This is a three-month open-label, multicenter, interventional, single arm study located in France, designed to assess feasibility and reliability of the e-Health ZEMY software medical device under investigation for use by participants with breast cancer, who are starting an anti-cancer treatment at any stage of the disease, to manage disease symptoms and anti-cancer treatment-related toxicities while at home.

Inclusion Criteria:

• Female patients with breast cancer starting a treatment including oral and/or parenteral anti-cancer drugs (chemotherapy and/or targeted therapies, hormonotherapy)
• Inter-cycle duration between hospital visits ≥14 days (this period of time is estimated to be consistent with a need for support during the home setting period)
• Patients shall be prescribed loperamide or any other anti-diarrheic treatment in case of diarrhea and prescription for any medication indicated in case of nausea/vomiting
• Able to speak and read French and to use a smartphone embedding ZEMY, in the investigator's judgment
• Able to comply with the study protocol, in the investigator's judgment
• Patient affiliated to the national social security or beneficiary to such insurance.

Exclusion Criteria:

• Pregnant
• Already enrolled in a clinical study involving experimental medication or eHealth device
• Concomitant malignancy
• ECOG score >2
• Treated with single hormonotherapy, single surgery or single radiotherapy, immunotherapy.
• Patient whose mental state renders her unable to understand the nature, purposes, and consequences of the study
• Patient not trained to the use of ZEMY
• Patient not trained to take her blood pressure measurement
• Patient deprived of her liberty by judicial or administrative order.