Pathological approach to breast conserving therapy.

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• The definition of a positive margin in breast-conserving surgery lacks universal agreement.
• The Japanese Breast Cancer Society's Guidelines for Breast-Conserving Treatment (GBCT) established a definition in 1999, differing from common practice at the time.

Purpose of the Study:

• To investigate the impact of different positive margin definitions on local recurrence rates after breast-conserving surgery.
• To identify significant risk factors for local recurrence in patients undergoing breast-conserving treatment.

Main Methods:

• A questionnaire survey assessed current definitions of margin status among hospitals/institutes.
• Retrospective analysis of 391 patients treated with breast-conserving surgery from 1986-1995 at Osaka Medical Center for Cancer and Cardiovascular Diseases.
• Multivariate analysis identified risk factors for local recurrence.

Main Results:

• Positive margin, high ductal proliferative change, and high histological grade were significant independent risk factors for local recurrence.
• Radiation therapy was found to significantly reduce local recurrence.
• No significant difference in local recurrence risk was observed between defining a positive margin as tumor at the surface versus within 5 mm of the surface.

Conclusions:

• Current definitions of positive margins in breast-conserving surgery are not uniform.
• A unified and practical definition of margin positivity is needed.
• Further adoption of the GBCT's definition is encouraged to standardize reporting and improve patient outcomes.