Tamoxifen and aromatase inhibitors are two oral hormonal therapies (OHT) that decrease the risk of breast cancer recurrence by over 30 %. Their efficacy however strongly depends on the duration of use (5 to 10 years). Earlier work demonstrated that the longer an individual is not taking her OHT the less likely she is to restart her therapy.

Thus, identifying the moment of treatment interruption in real-time and being able to contact the patient at these specific time-points may be the key to effective health interventions by improving medication adherence to reduce BC recurrence - therefore, increasing overall Breast Cancer survival (BCS). EHealth technologies may be a very effective mean to identify these interruptions in a real-time manner and to provide support at the time the person needs it.

The overall aim of the E-dherence Pilot study is to evaluate the feasibility of the E-Health intervention to enhance OHT adherence in BCS. Feasibility is defined based on 1.The eHealth intervention acceptability, 2. eHealth intervention quality and 3. medication adherence.

The study will include female breast cancer starting their first prescription of tamoxifen or aromatase inhibitors and are outpatient and followed-up in either of the 2 study sites. Participants should be 18 years or older and be fluent in french and or German and possess a smart-phone (iOS, Android). The investigators exclude males, patients with in situ metastatic tumors, inpatients and non Luxembourg residents.

Within the E-dherence Pilot study each patient receives the eHealth intervention.

The eHealth intervention consists a Medication Event Monitoring Systems (MEMS®) Helping Hand and MEMS Adherence Software application.

The eHealth intervention will support BCS to adhere to the recommended OHT (i) by alerting the participants to take their OHT, and (ii) by allowing patient-physician communication.

The intervention consists of a Medication Event Monitoring Systems (MEMS®), an electronic pillbox that counts the OHT intake, the date and time. Through Near Field Communication (NFC) the device is connected to the MEMS Adherence Software application on the patients' phone (Android or iOS). At the beginning, each patient can personalize the application. This application registers the history of OHT adherence (time and date of medication intake) and sends reminders to the patient to take the treatment as scheduled.

Additionally, the patient receives an integrated calendar in the App that notifies the patient for upcoming medical visits. The eHealth intervention comprises a questionnaire that should be filled-out weekly and that informs about the presence and severity of side effects. These data are collected in real-time and monitored on a weekly basis by the clinical research nurse (CRN) in charge of the study. In case of an alert, meaning recurrent non-adherence and/or reporting of side-effects, the CRN will contact the breast cancer nurse (BCN) in charge of the patient. Thus the BCN will contact the patient by phone to check on their health status and together define the future procedure in order for the patient to remain on OHT and/or to better manage their side-effects. In a worst case scenario, the BCN will refer the patient to see the emergency department and/or the oncologist.

The study received all ethical approvals.

Inclusion Criteria:

• Signed informed consent form
• Stated willingness to comply with all study procedures and availability for the duration of the study
• Female aged ≥18 years old
• 1st prescription of adjuvant treatment (Nolvadex, Arimidex)
• Treated in either the Centre Hospitalier du Luxembourg (CHL) or Centre Hospitalier Emile Mayrisch (CHEM)
• Luxembourg resident
• Fluent in French and/or German
• Outpatient
• Possession of a smart-phone (iOS, Android)

Exclusion Criteria:

• Male
• In situ or metastatic tumors
• Follow-up treatment outside of CHL or CHEM
• Non-Luxembourgish residents
• Inpatient

Female only