In each trial arm, mean time to AET treatment re-initiation will be calculated as the average number of days for a patient who has stopped taking AET treatment to start again, among those who start again (re-initiate).

In each trial arm, the proportion of patients that maintain a Medical Possession Ratio ≥80% will be calculated as the proportion patients whose proportion of number of days covered by medication supply in the treatment period is ≥80%.

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment or has discontinued AET treatment, for that patient, if a member of the cancer care team called the patient will be assessed qualitatively (yes/no) and quantitatively (if yes, time in number of days before the patient was called).

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment or has discontinued AET treatment, for that patient, if a member of the cancer care team called the patient's pharmacist will be assessed qualitatively (yes/no) and quantitatively (if yes, time in number of days before the patient's pharmacist was called).

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment or has discontinued AET treatment, for that patient, if a member of the cancer care team arranged for the patient to return to the clinic to see the doctor will be assessed qualitatively (yes/no) and quantitatively (if yes, time in number of days before the cancer care team arranged a return to clinic with doctor).

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment or has discontinued AET treatment, for that patient, if a member of the cancer care team arranged for the patient to return to the clinic to see the nurse will be assessed qualitatively (yes/no) and quantitatively (if yes, time in number of days before the cancer care team arranged a return to clinic with nurse).

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment or has discontinued AET treatment, for that patient, if a member of the cancer care team referred the patient to a doctor will be assessed qualitatively (yes/no) and quantitatively (if yes, time in number of days before the cancer care team referred the patient to a doctor). Note that this action is different than the outcome "arrange for return to clinic with doctor" because this outcome occurs when a nurse directly schedules a patient to see a specific doctor without discussing with a doctor first.

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment or has discontinued AET treatment, for that patient, if a member of the cancer care team referred the patient to a cancer nurse will be assessed qualitatively (yes/no) and quantitatively (if yes, time in number of days before the cancer care team referred the patient to a cancer nurse).

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment, for that patient, if no action by the cancer care team was taken will be assessed qualitatively (yes/no) and quantitatively (how many alerts per patient were ignored). Note that "ignore the alert" is an explicit option that care teams can specify. They will be trained to understand that the "ignore the alert" option represents that the patient has not discontinued AET treatment and that they are of the opinion that the patient is not at risk of discontinuing AET treatment despite reading the alert.

Upon alert receipt that a patient is at risk of discontinuing adjuvant endocrine therapy treatment or has discontinued AET treatment, for that patient, if no changes by the cancer care team were taken will be assessed qualitatively (yes/no) and quantitatively (how many alerts per patient were ignored). Note that this "no changes" is an explicit option that care teams can specify. They will be trained to understand that the "no changes" option represents that the patient requires other considerations beyond adhering to AET such as is stopping AET for upcoming surgery or no longer is indicated for AET based on disease progression (for e.g., brain metastases).

Any care team action that cannot be described by the predefined actions will be described by the care team in a free-text field for subsequent qualitative analysis. An overall theme or logical grouping of these qualitative outcomes will be explored and reported upon.