Real-World Application of Alliance ACOSOG Z11102: How Many Patients Can be Spared Mastectomy?

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• ACOSOG Z11102 trial established safety of breast-conserving surgery (BCS) for multiple ipsilateral breast cancers (MIBCs).
• The trial reported re-excision and mastectomy conversion rates of 32.4% and 7.1% respectively for MIBCs treated with BCS.
• Real-world applicability of these findings requires evaluation.

Purpose of the Study:

• To assess the real-world applicability of ACOSOG Z11102 criteria for BCS in patients with MIBC.
• To evaluate re-excision and mastectomy conversion rates in a contemporary cohort undergoing BCS for MIBC.

Main Methods:

• Retrospective review of MIBC patients' clinical and demographic data.
• Pathology re-review by two breast pathologists to assess inter-lesional distances and intervening tissue pathology.
• Analysis of re-excision and mastectomy conversion rates in patients treated with BCS.

Main Results:

• Of 46 BCS patients, 50% required re-excision, with a 26.1% overall conversion to mastectomy.
• The successful BCS rate was 73.9%, lower than trial data.
• Pathological review revealed significant findings in intervening tissue in many patients, including ductal carcinoma in situ (DCIS) and atypical hyperplasia (AH).

Conclusions:

• Patient selection is critical for BCS in MIBC.
• Real-world re-excision and mastectomy conversion rates for MIBC treated with BCS may be higher than previously reported.
• Further refinement of selection criteria for BCS in MIBC is warranted.