Effect of Preoperative Breast Mri Staging on Detection of Contralateral Breast Cancer (Cbc): Alliance A011104/Acrin 6694

Document Type

Conference Proceeding

Publication Date

5-1-2026

Publication Title

ESMO Open

Keywords

adult, aged, breast cancer, breast magnetic resonance imaging, cancer staging, clinical trial, cohort analysis, conference abstract, diagnosis, electrocorticography, follow up, human, human epidermal growth factor receptor 2 positive breast cancer, major clinical study, mastectomy, MRI scanner, nuclear magnetic resonance imaging, phase 3 clinical trial, radiotherapy, surgery, systemic therapy

Abstract

Background: ACRIN 6667 trial demonstrated that preoperative breast MRI identifies CBC in 3.1% of patients with a new diagnosis of breast cancer. However, whether early MRI detection of bilateral disease impacts subsequent diagnosis of CBC is unknown. The Alliance A011104 phase III trial tested the primary hypothesis that MRI detection of mammographically occult disease helps tailor surgical intervention and improves oncologic outcomes. Here we report on the secondary outcome of CBC events. Methods: Patients with stage I-II breast cancer, ER/PR-negative +/- HER2 overexpression, eligible for breast- conserving surgery were randomized to staging breast MRI or no further local staging. Known carriers of gBRCA 1/2, or patients with bilateral breast cancer, or prior history of breast cancer were excluded. Cumulative incidence of CBC was estimated with Kaplan Meier estimates. Patients with local regional recurrence (LRR) were censored at time of LRR. Results: 319 patients were enrolled; 161 randomized to breast MRI and 158 to no breast MRI. Twenty-one patients (14 MRI, 7 no MRI) who did not undergo surgery and 14 patients (6 MRI, 8 no MRI) who underwent bilateral mastectomy were excluded from analysis. 10 patients in the MRI arm had a contralateral lesion identified, with 2 confirmed malignant (1 in situ, 1 invasive). Patients in the MRI arm were younger (median age 58 vs 61 years, p=0.02), however there were no significant differences in clinical stage, proportion with HER2 overexpression, receipt of systemic therapy and adjuvant radiation between arms. With median follow-up of 61.1 months (0.2, 68.1), only 3 CBC events were observed, all in the no MRI arm (p=0.08) (5 year estimated rate of CBC 2.5% [0.8, 7.5]), at 37.6, 46.5 and 54.7 months from registration. Conclusions: CBC rate in patients with early stage triple-negative and HER2-positive breast cancer and without known gBRCA 1/2 is very low. While breast MRI may allow for earlier detection of CBC, the absolute benefit is marginal and may not justify routine use of preoperative breast MRI staging. Clinical trial identification: NCT01805076 https://acknowledgments.alliancefound.org Support: U10CA180821, U10CA180882; UG1CA189823; U10CA180820 (ECOG-ACRIN); U10CA180868 (NRG Oncology). Legal entity responsible for the study: Alliance for Clinical Trials in Oncology. Funding: National Cancer Institute USA Support: U10CA180821, U10CA180882; UG1CA189823; U10CA180820 (ECOG-ACRIN); U10CA180868 (NRG Oncology). Disclosure: All authors have declared no conflicts of interest.

Volume

11

First Page

107145

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