What is the purpose and management strategy of the ACOSOG (American College of Surgeons Oncology Group) Z11102 study for cancer treatment?

ACOSOG Z11102: Breast-Conserving Surgery for Multiple Ipsilateral Breast Cancer

Breast conservation therapy is feasible for patients with multiple ipsilateral breast cancer (MIBC), with only 7.1% requiring conversion to mastectomy due to positive margins, as demonstrated in the ACOSOG Z11102 trial. 1

Purpose and Design of ACOSOG Z11102

• ACOSOG Z11102 is a single-arm noninferiority trial designed to evaluate the feasibility of breast-conserving therapy (BCT) for women with two or three sites of malignancy in the ipsilateral breast 1
• Historically, multiple ipsilateral breast cancer was considered a contraindication to breast-conserving therapy, but this trial challenges that assumption 1
• The trial enrolled patients preoperatively to assess:
  • Conversion rates to mastectomy
  • Need for reoperation to obtain negative margins
  • Feasibility of successful breast conservation 1

Key Findings of ACOSOG Z11102

• Of 198 patients enrolled preoperatively, 96% had 2 foci of disease 1
• Median size of the largest tumor focus was 1.5 cm (range 0.1-7.0 cm) 1
• 24.8% of patients had positive lymph nodes 1
• The conversion to mastectomy rate was only 7.1% (95% CI 3.9-10.6%) 1
• 67.6% of patients achieved margin-negative excision in a single operation 1
• No specific patient characteristics were identified that significantly altered the risk of conversion to mastectomy or need for reexcision 1

Management Strategy in Context of Axillary Treatment

ACOSOG Z11102 builds on previous ACOSOG trials that have transformed breast cancer management, particularly regarding axillary treatment:

• ACOSOG Z0011 demonstrated that axillary lymph node dissection (ALND) is not necessary for women with early-stage breast cancer who have only 1 or 2 sentinel lymph node (SLN) metastases when receiving whole breast radiation therapy 2, 3
• The 10-year follow-up of ACOSOG Z0011 showed that overall survival for patients treated with sentinel lymph node dissection alone was noninferior to those treated with axillary lymph node dissection 3
• For patients with SLN micrometastases, multiple trials have confirmed that ALND can be safely avoided without compromising survival outcomes 2

Clinical Implications and Recommendations

• Patients with multiple ipsilateral breast cancer should be considered candidates for breast conservation therapy rather than automatically recommended for mastectomy 1
• For axillary management in these patients, follow standard guidelines based on sentinel lymph node status:
  • For patients with 1-2 positive SLNs who will receive whole breast radiation, ALND can be omitted 2, 3
  • For SLN micrometastases, ALND is not recommended 2
  • For patients with macrometastases in 1-2 SLNs, ALND or axillary radiation therapy are both valid options 2

Important Considerations and Caveats

• Patient selection is crucial - the trial included patients with predominantly 2 foci of disease with a median tumor size of 1.5 cm 1
• Multidisciplinary discussion is recommended when considering BCT for MIBC, particularly when determining adjuvant therapy needs 2
• Preoperative marking of tumor sites is important when planning BCT for multiple lesions 2
• The long-term oncologic outcomes of ACOSOG Z11102 will ultimately determine the true efficacy of this approach 1
• Recent ESMO guidelines support this less invasive approach to axillary management in appropriately selected patients 2

Conclusion

ACOSOG Z11102 represents an important advancement in breast cancer management by demonstrating that breast conservation is feasible in patients with multiple ipsilateral breast cancer. This approach allows many patients to avoid mastectomy while maintaining oncologic safety, continuing the trend toward less invasive surgical approaches in breast cancer treatment.