Evaluating Harms and Benefits of Endocrine Therapy in Patients ≥70 Years of Age With Lower Risk Breast Cancer

The current standard of care for stage 1 hormone receptor-positive (HR+) breast cancer consists of breast-conserving surgery followed by adjuvant radiotherapy (RT) and endocrine therapy (ET) for at least 5 years. The benefit of adjuvant ET for older patients is mitigated because of their increase risk of death from other causes and shorter time horizon to live. Clinical and pathological factors such as low-intermediate grade, tumor size ≤2 cm, and older age have been used in a few studies to identify patients with a lower risk of recurrence that might benefit from adjuvant therapy de-escalation, i.e. omission of RT or ET. Since there is no dedicated randomized clinical trial (RCT) conducted to evaluate the omission of ET, there is clinical equipoise as to whether we can omit adjuvant ET in older patients with lower-risk early-stage breast cancer. Therefore, we propose a randomised, multicentre trial evaluating harms and benefits of endocrine therapy in patients ≥70 years of age with lower risk breast cancer.

NCT Number	NCT04921137
Lead Sponsor	Ottawa Hospital Research Institute
Conditions	Breast Cancer
Enrollment	500 participants
Start Date	2021-08-19
Primary Completion	2036-05 (estimated)
Study Completion	2036-05 (estimated)
Updated on ClinicalTrials.gov	2026-05-28