The purpose of this study is to evaluate the feasibility of an mobile-health strategy to improve patient-reported symptoms, promote life-saving medication adherence, and encourage healthy lifestyle behaviors in early stage breast cancer survivors receiving adjuvant Aromatase inhibitors, while beginning to predict psycho-social and demographic characteristics of those who benefit most from this approach. This will provide preliminary experience and evidence for larger, randomized clinical trials evaluating this methodology, which will have immediate and scalable influence on cancer survivor ship.

This is a single arm, prospective, observational study enrolling up to 50 patients to the intervention in groups of 10 within Indiana University Simon Cancer Center. Subjects must meet eligibility at the time of informed consent. Once 10 eligible subjects are identified and have signed informed consent, each subject will return for their baseline visit and begin the app intervention with their group of 10.

Primary Objective Evaluate the feasibility of a smartphone application, LifeExtend-AI, in patients with early stage breast cancer currently prescribed aromatase inhibitor therapy, determined by patient usage of the application.

Secondary Objectives

1. Determine a preliminary estimate of effect size of the app intervention on medication adherence, by self- report using the Brief Medication Questionnaire
2. Determine a preliminary estimate of effect size of the app intervention on patient -reported AI arthralgia, as measured by the Basic Pain Inventory (BPI).
3. Determine a preliminary estimate of effect size of the app intervention on patient reported health associated quality of life, measured by the Functional Assessment of Cancer Therapy- Endocrine symptoms (FACT-ES) questionnaire.
4. Determine a preliminary estimate of the effect size of the app intervention on patient satisfaction with healthcare team communication, measured by the FACIT- Treatment Satisfaction-Patient Satisfaction questionnaire (FACIT-TS-PS).
5. Determine a preliminary estimate of effect size of the app intervention on patient reported health depression and anxiety, as measured by the Hospital Anxiety and Depression Scale (HADS).
6. Determine a preliminary estimate of effect size of the app intervention on patient reported physical activity level, as measured by the International Physical Activity Questionnaire (IPAQ).
7. Investigate psychosocial and behavioral determinants of application usage and subsequent medication adherence, including perceived AI necessity, fear of cancer recurrence, health self-efficacy, and e-health literacy.

Inclusion Criteria:

1. ≥ 18 years old at the time of informed consent

2. Regular access to a smartphone capable of downloading the application

   1. iOS 11 or later (iPhone5, iPhone SE or newer)
   2. Android 6 or later (Android 9 is current version)

3. History of DCIS, stage I, II, or III invasive breast cancer

4. Currently prescribed an aromatase inhibitor (letrozole, anastrozole, exemestane) or planned to be initiated on one by the time of signing informed consent. Patient already on an AI must have been prescribed this medication for a total of 36 months or less.

   1. Ovarian suppression with AI is allowed in premenopausal patients.
   2. Prior SERM and now switching to an AI for the first time is allowed.
   3. Concurrent trastuzumab, pertuzumab, or TDM1 is allowed.
   4. Concurrent neratinib or other oral cancer directed medication is not allowed.

5. ECOG performance status of 0-2

Exclusion Criteria:

1. Metastatic breast cancer or other active malignancy

   1. Locally recurrent breast cancer is allowed if treated with surgical excision and AI is prescribed with curative intent.
   2. History of prior treated malignancies, other than breast cancer, that are now stable, are in remission, and do not require active therapy, are acceptable

2. Unable to read the English language or otherwise participate in the study procedures in the opinion of the treating investigator.