Phase III Trial Finds No Oncologic Benefit from Routine Preoperative MRI in Early-Stage Breast Cancer
核心洞察
The Alliance A011104/ACRIN 6694 phase III trial found that preoperative breast MRI did not improve local regional recurrence (搜索), distant recurrence-free survival, or overall survival in patients with early-stage triple-negative and HER2-positive breast cancer (搜索).
Among 319 patients followed for a median of 61.1 months, 5-year local regional control rates were comparable between MRI and no-MRI groups at 93.2% and 95.7% respectively.
The findings suggest that routine preoperative breast MRI for staging newly diagnosed breast cancer (搜索) does not result in improved oncologic outcomes or surgical care.
Preoperative breast MRI failed to improve oncologic outcomes in patients with early-stage triple-negative and HER2-positive breast cancer (搜索), according to results from the phase III Alliance A011104/ACRIN 6694 trial presented at the 2025 San Antonio Breast Cancer (搜索) Symposium. The findings challenge the routine use of breast MRI for staging newly diagnosed breast cancer.
Study Design and Patient Population
The multicenter trial enrolled 319 patients with newly diagnosed clinical stage I to II breast cancer (搜索) across 73 sites, with 55% being academic centers and 45% community centers. Eligible patients had estrogen and progesterone receptor (搜索)-negative breast cancer that was either HER2 (搜索)-positive or HER2-negative (triple-negative), representing patient populations known to have the highest risk of recurrence.
Patients were randomly assigned in a 1:1 ratio to undergo staging breast MRI or not. Those assigned to the MRI arm had to undergo the scan within 30 days of mammography. The study excluded patients with germline BRCA1 (搜索)/2 mutations, bilateral breast cancer (搜索), or prior breast cancer history.
Primary Outcomes Show No Benefit
At a median follow-up of 61.1 months, the trial's primary endpoint of local regional recurrence (搜索) showed no significant differences between groups. The 5-year local regional control rate was 93.2% (95% CI = 89.0%-97.6%) in the MRI group compared to 95.7% (95% CI = 92.3%-99.1%) in the no-MRI group, with a hazard ratio of 1.1 (95% CI = 0.3-3.9).
"Preoperative breast MRI did not improve any of the oncologic outcomes that we measured: local regional recurrence (搜索), distance recurrence-free survival, or overall survival," said lead investigator Isabelle Bedrosian, MD, Professor of Breast Surgical Oncology at The University of Texas MD Anderson Cancer Center.
Secondary Endpoints Confirm Findings
The trial's secondary endpoints further supported the lack of benefit from preoperative MRI. The 5-year distant recurrence-free rate for the entire study population was 94.3% (95% CI = 91.7%-97.1%), with no differences between groups. Similarly, the 5-year overall survival rate was 92.2% (95% CI = 89.1%-95.4%), showing no significant variation between the MRI and no-MRI arms.
Subgroup analyses by age and receptor status also failed to demonstrate any significant benefit for preoperative breast MRI. Among patients younger than 50 years, local regional recurrence (搜索) events occurred in 2 of 30 patients in the MRI arm and 0 of 20 patients in the no-MRI arm.
Treatment Patterns and Surgical Outcomes
Of the enrolled patients, 93.4% underwent surgical intervention, with 91.9% receiving breast-conserving surgery. No significant differences in surgical approach were observed between groups (91.9% with MRI vs 92.7% without; P = .62). Eighty-five percent of patients received chemotherapy, with 17.6% receiving neoadjuvant chemotherapy following a protocol amendment.
Among patients who received neoadjuvant chemotherapy, the overall pathologic complete response rate was 39.3%. Notably, the rate was 52% in the no-MRI arm versus 29% in the MRI arm (P = .10). Adjuvant radiation rates were comparable between arms at approximately 85%.
Implications for Clinical Practice
Dr. Bedrosian noted that the local regional recurrence (搜索) rates were lower than anticipated during study design. She proposed two possible explanations for the negative results: "It is possible in the setting of chemotherapy and radiation therapy, resecting MRI-detected disease may not be necessary, that these are adequately treated with these other modalities of care that patients are already receiving."
Alternatively, she suggested that "advances in mammographic imaging that we have seen over the last 10 to 15 years, as well as the widespread use of ultrasound that we detected in our trial may have limited the utility of MRI for local staging."
The researchers concluded that the routine use of breast MRI for staging disease does not appear to be warranted, adding to the growing body of evidence that preoperative breast MRI for staging patients with newly diagnosed breast cancer (搜索) does not result in improved oncologic outcomes or surgical care.