See if older patients with low-risk HR+ breast cancer can skip endocrine therapy
Official title: A Randomised, Multicentre Trial Evaluating Harms and Benefits of Endocrine Therapy in Patients ≥70 Years of Age With Lower Risk Breast Cancer (REaCT-70)
Run by Ottawa Hospital Research Institute · NCT04921137 · Data updated 2026-11-12
This trial tests whether people aged 70 and older with low‑risk, hormone receptor–positive breast cancer can omit endocrine therapy after surgery and radiotherapy.
Quick facts
| Phase | Phase 4 |
|---|---|
| Study type | Interventional |
| Ages | 70 Years and up |
| Sex | All |
| Enrollment | 500 (estimated) |
| Sponsor | Ottawa Hospital Research Institute Academic / other |
| Locations | 8 sites (Edmonton, Alberta and 7 other locations) |
| Status | Recruiting |
| Started | August 19, 2021 |
| Main results expected | May 2036 |
| Study ends | May 2036 |
| Registry record updated | May 28, 2026 |
| Trial ID | NCT04921137 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are 70 years or older with low‑ to intermediate‑risk HR+/HER2‑ early breast cancer who completed breast-conserving surgery with radiotherapy (or mastectomy) and have node-negative disease.
✕Probably not a fit
Patients with higher-risk tumor features, axillary node involvement, or other health conditions that require endocrine therapy may not benefit from de-escalation.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This multicenter randomized trial compares omitting endocrine therapy versus giving endocrine therapy in adults aged 70 or older with low‑risk, early-stage HR+ breast cancer who have already received breast-conserving surgery or mastectomy with radiotherapy. The study focuses on harms, quality of life, and cancer outcomes to determine if de-escalation is safe in this population. Eligible participants have specific tumor characteristics, are HER2-negative, and can complete questionnaires in French or English. The trial addresses the balance between potential treatment-related adverse effects and the likelihood of cancer recurrence or progression in an older cohort.
Why it matters
Potential benefit: If successful, the approach could spare some older patients the side effects of endocrine therapy without compromising cancer control.
How similar studies have gone: Some prior studies and analyses suggest that omitting endocrine therapy may be feasible in select older patients, but dedicated randomized evidence is lacking until now.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * New invasive estrogen and/or progesterone receptor-positive (ER+ and/or PR+), HER2-negative (HER2-) invasive breast carcinoma diagnosis as per ASCO-CAP guidelines * The primary tumour characteristics are either: Grade 1 and ≤3 cm on microscope exam, OR Grade 2 and ≤2 cm on microscope exam, OR Grade 3 and ≤1 cm on microscope exam * Treated with standard loco-regional therapy: breast conserving surgery followed by adjuvant radiotherapy OR total mastectomy * Axillary node-negative (cN0 or pN0) * Able to provide oral consent and complete questionnaires in French or English as per study protocol Exclusion Criteria: * Metastatic cancer
Where it's running
-
The Ottawa Hospital
Ottawa, Ontario, Canada Recruiting -
Cross Cancer Institute
Edmonton, Alberta, Canada Not yet recruiting -
Waterloo Regional Health Network
Kitchener, Ontario, Canada Active not recruiting -
London Health Sciences Centre
London, Ontario, Canada Active not recruiting -
Oak Valley Health
Markham, Ontario, Canada Active not recruiting -
Thunder Bay Regional Health Sciences Centre
Thunder Bay, Ontario, Canada Active not recruiting
Show 2 more locations
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Allan Blair Cancer Centre
Regina, Saskatchewan, Canada Active not recruiting -
Saskatoon Cancer Centre
Saskatoon, Saskatchewan, Canada Active not recruiting
Study contacts
- Principal investigator: Marie-France Savard, MD — Ottawa Hospital Research Institute
- Study coordinator: Lisa Vandermeer, MSc
- Email: lvandermeer@ohri.ca
- Phone: 613-737-7700
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.