Implementation Study to Describe and Compare Retention Rate and Adherence to Adjuvant Therapy With Ribociclib With and Without Usage of Mobile Application in Patients With HR+ HER2-negative Stage II and III Breast Cancer in Real-world Practice

Inclusion Criteria:

1. Female and male patients with histologically verified and radically treated stage II-III hormone receptor positive HER2-negative breast cancer;
2. Age ≥ 18 at the time of initiation of ribociclib therapy;
3. Patients who were prescribed ribociclib + AI (±GnRH agonist for premenopausal men and women) not earlier than 28 days before signing the informed consent;
4. It is allowed to start adjuvant hormone therapy with AI (±GnRH agonist) not earlier than 12 months before the start of ribociclib;
5. Provision of written informed consent.

Exclusion Criteria:

1. Patients participating in any interventional clinical study at the time of signing the informed consent;
2. Patients receiving active treatment for malignant neoplasms other than BC at the time of enrollment.