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Hormone Therapy

Endocrine Therapy for Older Patients with Breast Cancer

Phase 4
Led By Marie-France Savard, MD
Research Sponsored by Ottawa Hospital Research Institute
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
The primary tumour characteristics are either: Grade 1 and ≤5 cm on microscope exam, OR Grade 2 and ≤3 cm on microscope exam, OR Grade 3 and ≤1 cm on microscope exam
New invasive estrogen and/or progesterone receptor-positive (ER+ and/or PR+), HER2-negative (HER2-) invasive breast carcinoma diagnosis as per ASCO-CAP guidelines
Must not have
Metastatic cancer
Screening 3 weeks
Treatment Varies
Follow Up 4 weeks after study enrolment
Awards & highlights


This trial will compare the effects of omitting adjuvant ET versus standard of care in older patients with lower risk breast cancer.

Who is the study for?
This trial is for patients aged 70 or older with early-stage, lower-risk hormone receptor-positive breast cancer. They must be able to consent and fill out questionnaires in French or English, have a new diagnosis of certain types of breast carcinoma, and have undergone specific surgeries without metastatic cancer.Check my eligibility
What is being tested?
The study is testing the necessity of endocrine therapy (ET) after surgery in older patients with low-risk breast cancer. It randomly assigns participants to either receive ET or no ET post-surgery to see if omitting ET can still effectively manage their condition.See study design
What are the potential side effects?
Endocrine therapy may cause hot flashes, fatigue, mood swings, reduced sex drive, bone thinning (osteoporosis), joint pain, and an increased risk of blood clots.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
My tumor is small and varies in aggressiveness based on its size.
My breast cancer is ER+ and/or PR+, and HER2-.
I had surgery to remove my breast cancer and then received radiation.
My cancer has not spread to the lymph nodes under my arm.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:
My cancer has spread to other parts of my body.


Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~4 weeks after study enrolment
This trial's timeline: 3 weeks for screening, Varies for treatment, and 4 weeks after study enrolment for reporting.

Treatment Details

Study Objectives

Outcome measures can provide a clearer picture of what you can expect from a treatment.
Primary outcome measures
90% treatment allocation rate
Accrual of 100 participants across 8 centres within 2 years
Participation rate of at least 60%
Secondary outcome measures
Endocrine therapy related toxicity
Health-related quality of life scores
Rate of treatment discontinuation
+1 more

Trial Design

2Treatment groups
Experimental Treatment
Active Control
Group I: Omission of endocrine therapyExperimental Treatment1 Intervention
Omission of endocrine therapy
Group II: Administration of endocrine therapy for at least 5 yearsActive Control1 Intervention
Administration of endocrine therapy for at least 5 years

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.
Mechanism Of Action
Side Effect Profile
Prior Approvals
Other Research
Endocrine therapies, such as tamoxifen and aromatase inhibitors (e.g., anastrozole), are commonly used to treat hormone receptor-positive breast cancer. Tamoxifen works by blocking estrogen receptors on breast cancer cells, preventing estrogen from binding and stimulating cancer growth. Aromatase inhibitors reduce the production of estrogen in postmenopausal women by inhibiting the enzyme aromatase, which converts androgens to estrogen. These treatments are crucial for reducing the risk of cancer recurrence and improving survival rates in patients with hormone receptor-positive breast cancer. Understanding their mechanisms helps in tailoring treatment plans, especially for older patients with lower-risk profiles, where the balance between benefits and potential side effects must be carefully considered.
Extended Adjuvant Endocrine Therapy in Breast Cancer: Evidence and Update - A Review.Implementing neoadjuvant endocrine strategies in ER-positive, HER2-negative breast cancer.Extending the clinical benefit of endocrine therapy for women with hormone receptor-positive metastatic breast cancer: differentiating mechanisms of action.

Find a Location

Who is running the clinical trial?

Ottawa Hospital Research InstituteLead Sponsor
565 Previous Clinical Trials
2,786,073 Total Patients Enrolled
34 Trials studying Breast Cancer
5,161 Patients Enrolled for Breast Cancer
Marie-France Savard, MDPrincipal InvestigatorOttawa Hospital Research Institute
2 Previous Clinical Trials
487 Total Patients Enrolled
2 Trials studying Breast Cancer
487 Patients Enrolled for Breast Cancer

Media Library

Endocrine therapy (Hormone Therapy) Clinical Trial Eligibility Overview. Trial Name: NCT04921137 — Phase 4
Breast Cancer Research Study Groups: Omission of endocrine therapy, Administration of endocrine therapy for at least 5 years
Breast Cancer Clinical Trial 2023: Endocrine therapy Highlights & Side Effects. Trial Name: NCT04921137 — Phase 4
Endocrine therapy (Hormone Therapy) 2023 Treatment Timeline for Medical Study. Trial Name: NCT04921137 — Phase 4
~26 spots leftby Jul 2025