Local Recurrence After Breast-Conserving Therapy in Patients With Multiple Ipsilateral Breast Cancer: Results From...

Area of Science:

• Oncology
• Surgical Oncology
• Radiation Oncology

Background:

• Breast-conserving therapy (BCT) is standard for unifocal breast cancer.
• The oncologic safety of BCT for multiple ipsilateral breast cancer (MIBC) requires prospective evaluation.

Purpose of the Study:

• To assess the oncologic outcomes of BCT in patients with MIBC.
• To determine the 5-year cumulative incidence of local recurrence (LR) following BCT for MIBC.

Main Methods:

• ACOSOG Z11102 (Alliance) was a phase II, single-arm, prospective trial.
• Eligible patients (age ≥40) had 2-3 foci of biopsy-proven cN0-1 breast cancer.
• Treatment involved lumpectomies with negative margins and whole breast radiation with boost to lumpectomy beds.

Main Results:

• Six of 204 eligible patients developed LR at 5 years, yielding a cumulative incidence of 3.1% (95% CI, 1.3 to 6.4).
• No significant association was found between LR risk and patient age, tumor characteristics, or biomarker status.
• A significantly lower 5-year LR rate was observed in patients who underwent preoperative MRI (1.7%) compared to those who did not (22.6%).

Conclusions:

• BCT with lumpectomy site boosts demonstrates an acceptably low 5-year LR rate for MIBC.
• This supports BCT as a reasonable surgical option for women with 2-3 ipsilateral breast cancer foci.
• Preoperative MRI may further refine patient selection for BCT in MIBC.