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Comparing two radiation treatments for breast cancer

Randomized Trial of Hypofractionated LocoRegional Radiotherapy in Breast Cancer and Lymphedema (RHEAL)

PHASE3 · Ontario Clinical Oncology Group (OCOG) · NCT04228991

This study is testing whether a quicker radiation treatment over one week is just as effective and safe as the standard three-week treatment for people with node-positive breast cancer after surgery.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment588 (estimated)
Ages18 Years and up
SexAll
SponsorOntario Clinical Oncology Group (OCOG) (other)
Drugs / interventionschemotherapy, radiation
Locations20 sites (Calgary, Alberta and 19 other locations)
Trial IDNCT04228991 on ClinicalTrials.gov

What this trial studies

This phase III clinical trial aims to compare hypofractionated radiotherapy delivered over one week to conventional radiotherapy delivered over three weeks in patients with node-positive breast cancer. Participants will be randomly assigned to receive either treatment after definitive surgery, and their outcomes will be assessed for lymphedema, arm mobility, radiation toxicities, breast cancer recurrence, quality of life, and overall survival. The study will involve 588 participants across multiple clinical centers in Canada.

Who should consider this trial

Good fit: Ideal candidates are patients with newly diagnosed invasive breast cancer who have undergone definitive surgery and are candidates for locoregional radiotherapy.

Not a fit: Patients with metastatic breast cancer or those who have not undergone definitive surgery will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a more efficient and potentially less toxic radiation treatment option for breast cancer patients.

How similar studies have performed: Other studies have shown promising results with hypofractionated radiation approaches, suggesting potential for success in this trial.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Newly diagnosed invasive carcinoma of the breast.
2. Treated with definitive surgery (BCS or mastectomy with nodal staging using SLNB or ALND) with clear margins of excision.\* Note: \*Patients with limited positive posterior margin where disease is resected to chest wall or limited positive anterior margin where disease is resected to dermis are eligible.
3. Candidate for locoregional radiotherapy: breast cancer stage after definitive surgery:

   * Neoadjuvant chemotherapy was not administered: pathologic stage T3N0,T1-3 N1-2\*\*

     \*\* patients with nodal micromets (N1mi) are eligible
   * Neoadjuvant chemotherapy was administered: clinical stage T3N0, T1-3, N1-2 and pathologic stage T0-3, N0-2†

     * Patients who are clinically N1-2 prior to chemotherapy should be confirmed histologically unless it is clear that they are node positive. Patients who are deemed node negative prior to chemotherapy but are node positive following chemotherapy are eligible. Patients who are node positive prior to chemotherapy and who have complete response in the lymph nodes are also eligible.
4. No evidence of metastatic disease.

Exclusion Criteria:

1. Age \< 18 years.
2. Clinical stages T4 and/or N3.
3. Clinical lymphedema in the ipsilateral arm or breast/chest wall.
4. Any prior history, not including index cancer, of ipsilateral invasive breast cancer or ipsilateral DCIS treated with radiation therapy. (Patients with previous ipsilateral DCIS or LCIS not treated with radiation are eligible.)
5. Synchronous or previous contralateral breast cancer.(Patients with previous contralateral DCIS or LCIS not treated with radiation are eligible.)
6. History of non-breast malignancy within the last 5 years other than non-melanoma skin cancer or treated in-situ carcinoma.
7. Neoadjuvant endocrine therapy. (Extended neoadjuvant endocrine therapy is not permitted. Endocrine therapy exposure for 12 weeks or less prior to surgery is acceptable.)
8. Breast reconstruction.
9. Presence of known medical conditions that would preclude follow-up for 5 years.
10. Previous radiotherapy to the ipsilateral breast or chest wall or serious non-malignant disease e.g. scleroderma, severe lung or heart disease that would preclude radiotherapy.
11. Known pregnancy or currently lactating.
12. Geographic inaccessibility for follow-up.
13. Inability to provide informed consent.

Where this trial is running

Calgary, Alberta and 19 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Breast Neoplasms, Radiotherapy, Lymphedema, Hypofractionated, Locoregional, Breast Cancer

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.