A Phase 3 interventional study of Radiation and Endocrine Therapy (Tamoxifen, Anastrozol, Letrozole, Exemestane) and Endocrine Therapy (Tamoxifen, Anastrozol, Letrozole, Exemestane) in Stage I Breast Cancer, sponsored by NRG Oncology. Recruiting at 832 sites in 4 countries. Open to participants aged 50 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-04-23.
Sponsored by NRG Oncology · Phase 3, Interventional, and Treatment
This Phase III Trial evaluates whether breast conservation surgery and endocrine therapy results in a non-inferior rate of invasive or non-invasive ipsilateral breast tumor recurrence (IBTR) compared to breast conservation with breast radiation and endocrine therapy.
Breast conservation therapy for early stage breast cancer has been an important achievement of oncology practice in the last half century and breast radiotherapy (RT) has been essential in its development. Several seminal randomized clinical trials conducted in the 1980's era demonstrated that breast radiotherapy following lumpectomy yielded overall survival outcomes equivalent to mastectomy for treatment of early stage invasive breast cancer leading to the National Institute of Health (NIH) Consensus Conference statement in 1991 supporting breast conservation treatment.This established lumpectomy with RT as an alternative to mastectomy and subsequently the rate of breast conservation for eligible breast cancer patients rose steadily. Shortly thereafter, investigators recognized that the toxicity, patient burden, and geographic barriers associated with the protracted treatment course for breast RT was a potential barrier to breast conservation utilization. Numerous phase III clinical trials were conducted randomizing women post lumpectomy to RT vs. observation aimed at identifying which cases did not derive a significant RT benefit. No such subsets of breast cancer patients were consistently identified, thereby solidifying the standard that breast conservation required both lumpectomy and RT. Two meta-analyses by the Early Breast Cancer Trialists Collaborative Group (EBCTCG) in 2005 and 2011 further reinforced the value of breast RT post lumpectomy by examining the relationship of local recurrence and breast cancer mortality relative to the use of breast RT post lumpectomy. In each analysis, it found for axillary node negative breast cancer patients undergoing breast conservation a small but consistent increase in breast cancer mortality when breast radiotherapy was omitted. As a result, breast RT after lumpectomy has become an established paradigm for breast conservation for early stage breast cancer and is recommended by the NCCN 2018 guidelines (as it has for nearly two decades) that are commonly used today by clinicians and health systems alike. The landscape of early stage breast cancer has changed dramatically over the past three decades since the establishment of breast conservation. Widespread screening with mammography has led to the diagnosis of smaller and earlier stage disease. All breast cancers are now routinely characterized by their hormone sensitivity based on the presence of estrogen and progesterone receptors on tumor cells within the biopsy or surgical specimen and presence of HER2 (human epidermal growth factor receptor 2) which has provided an additional means of stratifying breast cancer into distinct prognostic groups. Small, node negative invasive breast cancer that is hormone sensitive (HS) and HER2-negative has a lower overall recurrence rate (local, regional, and distant) than breast cancers characterized by more adverse clinical pathologic features. However, other than in a smaller subset of women greater than 70 years old, clinical trials in this HS population still demonstrated unacceptable local recurrence risks long term after lumpectomy alone emphasizing that clinical and pathologic features are insufficient for consistently identifying when RT can safely be omitted.
12,544 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.
This study's planned enrollment of 1,670 is above the median of 72 across 9,303 interventional studies indexed under Breast Neoplasms.
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The patient or a legally authorized representative must provide study-specific informed consent prior to pre-entry/Step 1 and, for patients treated in the U.S., authorization permitting release of personal health information.
Oncotype DX Recurrence Score of less than or equal to 18 on diagnostic core biopsy or resected specimen.
** For patients with a T1a tumor (less than or equal to 0.5 cm in size) or patients at Canadian provinces or approved international sites where Oncotype DX Recurrence Score testing would not be covered, who do not already have an Oncotype DX Recurrence Score at pre-entry/Step 1, a specimen (unstained blocks or slides) must be sent to the Genomic Health centralized laboratory. Tumor size sample must be greater than or equal to 0.2 cm for analysis.
*** The Oncotype RS can be run on the biopsy core or surgical specimen. The patient cannot have initiated endocrine therapy prior to tissue collection.
Exclusion Criteria:
Definitive clinical or radiologic evidence of metastatic disease.
Current therapy with any endocrine therapy such as raloxifene (Evista®), tamoxifen, or other selective estrogen receptor modulators (SERMs), either for osteoporosis or breast cancer prevention.
** Patients are eligible for BR007 if they receive a short course of preoperative endocrine therapy of less than 6 weeks duration (prior to randomization/Step 2) for this diagnosis after the core biopsy (and can continue postoperatively if:
the patient had not initiated endocrine therapy prior to core biopsy tissue collection.
*** This does not apply to adjuvant endocrine therapy recommended for this diagnosis which may start any time after surgery including prior to registration (Pre-entry/Step 1).
Radiation therapy to the breast and hormonal drug for at least 5 years. Tamoxifen 20 mg daily Anastrozole 1 mg daily Letrozole 2.5 mg daily Exemestane 25 mg daily
Other: Radiation and Endocrine Therapy (Tamoxifen, Anastrozol, Letrozole, Exemestane)
No radiation therapy, only hormonal drug for at least 5 years. Tamoxifen 20 mg daily Anastrozole 1 mg daily Letrozole 2.5 mg daily Exemestane 25 mg daily
Drug: Endocrine Therapy (Tamoxifen, Anastrozol, Letrozole, Exemestane)
Post lumpectomy radiation therapy will be external beam radiation to either the whole breast + boost, partial breast irradiation, or Accelerated Partial Breast Irradiation that must begin within 12 weeks of the last breast cancer surgery(including re-excision of margins). Endocrine therapy for a minimum of 5 years. The specific regimen of endocrine therapy is at the treating physician's discretion. The dose and schedule of the drug(s) used for endocrine therapy should be consistent with the instructions in the drug package insert(s). Endocrine therapy may be initiated before, during, or after completion of radiation therapy at the discretion of the investigator.
Endocrine therapy for a minimum of 5 years. The specific regimen of endocrine therapy is at the treating physician's discretion. The dose and schedule of the drug(s) used for endocrine therapy should be consistent with the instructions in the drug package insert(s).
Time to invasive or noninvasive IBTR.
Time from randomization to any invasive or noninvasive IBTR or last follow-up (expressed as % IBTR-free)
Time frame: 5 years
Percent of women with an intact index breast at report of the primary endpoint inclusive of salvage second breast conservation procedures.
Time from randomization to any breast procedure after the initial surgery or last follow-up (expressed as % with intact index breast)
Time frame: Through study completion, an average of 15 years.
Time from randomization to the first occurrence of invasive ipsilateral breast tumor recurrence.
Time from randomization to any invasive IBTR or last follow-up (expressed as percentage of invasive IBTR-free
Time frame: 5 years
Time from randomization to diagnosis of a local, regional or distant recurrence as a first cancer event.
Time from randomization to any breast cancer recurrence at a local, regional or distant site or last follow-up (expressed as percentage of recurrence-free)
Time frame: 5 years
Time from randomization to the first distant cancer event (either a recurrence or a secondary primary cancer).
Time from randomization to any cancer occurring at a distant site or last follow-up (expressed as percentage of distant disease-free)
Time frame: 5 years
Time from randomization to any death.
Time from randomization to any death or last follow-up (expressed as percent surviving)
Time frame: 5 years
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