Anatomic Stage I Breast Cancer AJCC v8Phase 2NCT03624478
Hypofractionated Radiation Therapy in Treating Participants With Breast Cancer Before Surgery
A Phase 2 study testing Hypofractionated Radiation Therapy in people with Anatomic Stage I Breast Cancer AJCC v8 and Anatomic Stage IA Breast Cancer AJCC v8, run by Mayo Clinic at 3 sites in United States.
Trial summary
This phase II trial studies how well hypofractionated radiation therapy works in treating participants with breast cancer before surgery. Hypofractionated radiation therapy delivers higher doses of radiation therapy over a shorter period of time and may kill more tumor cells and have fewer side effects. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Anatomic Stage I Breast Cancer AJCC v8, Anatomic Stage IA Breast Cancer AJCC v8, Anatomic Stage IB Breast Cancer AJCC v8
- What is being tested?
- Hypofractionated Radiation Therapy
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- 3 sitesUnited States
- Study dates
- 20 Nov 2018to 24 Sep 2025
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Histological confirmation of breast cancer
- Clinical stage T0-T2 N0 M0
- Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 to 2
- Able to and provides Institutional Review Board (IRB) approved study specific written informed consent
- Study entry must be within 120 days of last biopsy (breast)
- Able to complete all mandatory tests
- Willing to return to enrolling institution for follow-up (during the active monitoring phase of the study)
- Planned breast surgery and indications for whole breast radiotherapy
Who cannot join
- Medical contraindication to receipt of radiotherapy
- Severe active co-morbid systemic illnesses or other severe concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens
- Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements or providing informed consent
- Active systemic lupus or scleroderma
- Pregnancy
- Women of childbearing potential who are unwilling to employ adequate contraception
Show all 10Show fewer
- Prior receipt of ipsilateral breast or chest wall radiation
- Recurrent breast cancer
- Indications for comprehensive regional nodal irradiation
- No neo-adjuvant therapy
Trial locations and contacts
3 sites in 1 country.
United States3 sites
Mayo Clinic in Florida
Jacksonville, Florida, 32224-9980
Mayo Clinic
Rochester, Minnesota, 55905
Mayo Clinic in Arizona
Scottsdale, Arizona, 85259
About this study
Official title: A Pilot/Phase II Trial of Hypofractionated Radiotherapy to the Whole Breast Alone Before Breast Conserving Surgery
This phase II trial studies how well hypofractionated radiation therapy works in treating participants with breast cancer before surgery. Hypofractionated radiation therapy delivers higher doses of radiation therapy over a shorter period of time and may kill more tumor cells and have fewer side effects.
Read the detailed description
PRIMARY OBJECTIVES:
- To determine the pathologic complete response (pCR) rate after hypofractionated radiotherapy to the whole breast alone, based on the postsurgical specimen.
SECONDARY OBJECTIVES:
- To evaluate acute and late toxicity with preoperative radiation including grade >= 2 pneumonitis.
II. To estimate the 5-year locoregional control, distant recurrence, invasive disease-free survival, cause-specific survival, and overall survival.
CORRELATIVE AND EXPLORATORY OBJECTIVES:
- To evaluate patient-reported outcomes. II. To evaluate clinical features, treatment technique, dose-volume parameters, histologic and genetic variants associated with adverse events, and fair and poor cosmetic outcomes or unplanned surgical intervention.
III. Evaluate tumor mutation signatures before and after radiation; correlate tumor mutation signatures before and after radiation with pathologic information at the time of surgery.
IV. To describe the pathologic changes seen in breast cancer patients with preoperative radiation.
OUTLINE:
Participants undergo hypofractionated radiation therapy daily for 5 days, then undergo standard of care surgery 4-16 weeks after radiation therapy.
After completion of study treatment, participants are followed up at 12 weeks, 6, 12, 24, and 36 months, and 5 years after radiation therapy.
- Conditions
- Anatomic Stage I Breast Cancer AJCC v8, Anatomic Stage IA Breast Cancer AJCC v8, Anatomic Stage IB Breast Cancer AJCC v8, Anatomic Stage IIA Breast Cancer AJCC v8, Prognostic Stage I Breast Cancer AJCC v8, Prognostic Stage IA Breast Cancer AJCC v8
- Being tested
- Hypofractionated Radiation Therapy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Hypofractionated Radiation TherapyRadiation
Also called Hypofractionated Radiotherapy, hypofractionation
Undergo hypofractionated radiation therapy
| Study group | Role | What they receive |
|---|---|---|
| Treatment (hypofractionated radiation therapy) | Experimental | Participants undergo hypofractionated radiation therapy daily for 5 days, then undergo standard of care surgery 4-16 weeks after radiation therapy. Receives: Radiation: Hypofractionated Radiation Therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pathologic Complete Response (pCR) Rate Defined as a Residual Tumor Burden of 0-1 in the Surgical Specimen
The proportion of successes (number of patients achieving pCR at time of definitive surgery) will be estimated by the number of successes divided by the total number of evaluable patients. Confidence intervals for the true success proportion will be calculated according to the approach of Duffy and Santner.
Measured: up to 2 years
Secondary outcomes (8)
Number of Participants With Acute Adverse Events (AE)
The maximum grade for each type of acute AE will be recorded for each patient. Data will be summarized as frequencies and relative frequencies. Additionally, the relationship of the adverse event(s) to the study treatment will be taken into consideration.
Measured: Up to 180 days post radiation therapy
Incidence of Late Adverse Events
The maximum grade for each type of late AE will be recorded for each patient. Data will be summarized as frequencies and relative frequencies by treatment arm. Additionally, the relationship of the adverse event(s) to the study treatment will be taken into consideration.
Measured: Up to 5 years post radiation therapy
Locoregional Control
The cumulative incidence of locoregional recurrence will be estimated using a competing risks method (Gooley et al.). The competing risks will be distant breast cancer recurrence and death.
Measured: Up to 5 years
Invasive Disease-free Survival
Will be estimated with a Kaplan-Meier estimator and curve. Estimates will be given for specific time points along with 95% confidence intervals (CIs).
Measured: From registration until the time of disease recurrence or death due to any cause, assessed up to 5 years
Distant Recurrence
Measured: Up to 5 years
Disease- Free Survival
Will be estimated with a Kaplan-Meier estimator and curve. Estimates will be given for specific time points along with 95% CIs.
Measured: From registration until the time of disease recurrence or death due to any cause, assessed up to 5 years
Cause-specific Survival
Will be estimated with a Kaplan-Meier estimator and curve. Estimates will be given for specific time points along with 95% CIs.
Measured: From registration to death due to breast cancer assessed up to 5 years
Overall Survival
Will be estimated with a Kaplan-Meier estimator and curve. Estimates will be given for specific time points along with 95% CIs.
Measured: From registration to death due to any cause assessed up to 5 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Aug 2018
- Study start20 Nov 2018
- Primary completion30 Jun 2021
- Study completion24 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Anatomic Stage I Breast Cancer AJCC v8Studies of the same condition, open and under way.
- More trials run by Mayo ClinicThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- Mayo Clinic
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Carlos E. Vargas, M.D., Principal investigator, Mayo Clinic
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03624478
- Sponsor's protocol ID
- MC1732
- Other IDs
- 17-004130
- Status last verified
- Nov 2025
- First submitted
- 6 Aug 2018
- Last updated
- 15 May 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 15 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Pilot/Phase II Trial of Hypofractionated Radiotherapy to the Whole Breast Alone Before Breast Conserving Surgery
- ClinicalTrials.gov ID
- NCT03624478
- Acronym / sponsor ID
- MC1732
- Conditions
- Anatomic Stage I Breast Cancer AJCC v8, Anatomic Stage IA Breast Cancer AJCC v8, Anatomic Stage IB Breast Cancer AJCC v8, Anatomic Stage IIA Breast Cancer AJCC v8, Prognostic Stage I Breast Cancer AJCC v8, Prognostic Stage IA Breast Cancer AJCC v8
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 25 participants (actual)
- Lead sponsor
- Mayo ClinicUniversity, hospital or other
- Study start
- 20 Nov 2018 (actual)
- Primary completion
- 30 Jun 2021 (actual)
- Study completion
- 24 Sep 2025 (actual)
- First posted
- 10 Aug 2018 (actual)
- Results
- Posted 15 Dec 2022
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This phase II trial studies how well hypofractionated radiation therapy works in treating participants with breast cancer before surgery. Hypofractionated radiation therapy delivers higher doses of radiation therapy over a shorter period of time and may kill more tumor cells and have fewer side effects.
Detailed description
PRIMARY OBJECTIVES:
- To determine the pathologic complete response (pCR) rate after hypofractionated radiotherapy to the whole breast alone, based on the postsurgical specimen.
SECONDARY OBJECTIVES:
- To evaluate acute and late toxicity with preoperative radiation including grade >= 2 pneumonitis.
II. To estimate the 5-year locoregional control, distant recurrence, invasive disease-free survival, cause-specific survival, and overall survival.
CORRELATIVE AND EXPLORATORY OBJECTIVES:
- To evaluate patient-reported outcomes. II. To evaluate clinical features, treatment technique, dose-volume parameters, histologic and genetic variants associated with adverse events, and fair and poor cosmetic outcomes or unplanned surgical intervention.
III. Evaluate tumor mutation signatures before and after radiation; correlate tumor mutation signatures before and after radiation with pathologic information at the time of surgery.
IV. To describe the pathologic changes seen in breast cancer patients with preoperative radiation.
OUTLINE:
Participants undergo hypofractionated radiation therapy daily for 5 days, then undergo standard of care surgery 4-16 weeks after radiation therapy.
After completion of study treatment, participants are followed up at 12 weeks, 6, 12, 24, and 36 months, and 5 years after radiation therapy.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Treatment (hypofractionated radiation therapy) | Experimental | Radiation: Hypofractionated Radiation TherapyParticipants undergo hypofractionated radiation therapy daily for 5 days, then undergo standard of care surgery 4-16 weeks after radiation therapy. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Histological confirmation of breast cancer
- Clinical stage T0-T2 N0 M0
- Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 to 2
- Able to and provides Institutional Review Board (IRB) approved study specific written informed consent
- Study entry must be within 120 days of last biopsy (breast)
Key exclusion criteria (10 listed)
- Medical contraindication to receipt of radiotherapy
- Severe active co-morbid systemic illnesses or other severe concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens
- Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements or providing informed consent
- Active systemic lupus or scleroderma
- Pregnancy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Hypofractionated Radiation TherapyAlso: Hypofractionated Radiotherapy, hypofractionationUndergo hypofractionated radiation therapy | Radiation | Treatment (hypofractionated radiation therapy) |
Primary outcome
Pathologic Complete Response (pCR) Rate Defined as a Residual Tumor Burden of 0-1 in the Surgical Specimen
Time frame: up to 2 years
The proportion of successes (number of patients achieving pCR at time of definitive surgery) will be estimated by the number of successes divided by the total number of evaluable patients. Confidence intervals for the true success proportion will be calculated according to the approach of Duffy and Santner.
8 secondary outcomes
Number of Participants With Acute Adverse Events (AE)
Time frame: Up to 180 days post radiation therapy
Incidence of Late Adverse Events
Time frame: Up to 5 years post radiation therapy
Locoregional Control
Time frame: Up to 5 years
Invasive Disease-free Survival
Time frame: From registration until the time of disease recurrence or death due to any cause, assessed up to 5 years
Distant Recurrence
Time frame: Up to 5 years
Disease- Free Survival
Time frame: From registration until the time of disease recurrence or death due to any cause, assessed up to 5 years
Cause-specific Survival
Time frame: From registration to death due to breast cancer assessed up to 5 years
Overall Survival
Time frame: From registration to death due to any cause assessed up to 5 years
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 May 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Mayo Clinic Clinical TrialsLink provided by the sponsor.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Carlos E. Vargas, M.D. principal investigator
Mayo Clinic
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Hypofractionated Radiation Therapy in people with Anatomic Stage I Breast Cancer AJCC v8 and Anatomic Stage IA Breast Cancer AJCC v8, run by Mayo Clinic at 3 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 15 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 15 Dec 2022). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pathologic Complete Response (pCR) Rate Defined as a Residual Tumor Burden of 0-1 in the Surgical Specimen (time frame: up to 2 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 May 2026.