Margin index: a useful tool for the breast surgeon?

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• Surgical margin assessment is critical in breast conservation surgery (BCS) for breast cancer.
• The margin index, a ratio of tumor size to closest margin, has shown potential in predicting residual cancer.
• Its utility in predicting residual disease after BCS requires further validation.

Purpose of the Study:

• To evaluate the predictive ability of the margin index for residual breast cancer in patients undergoing re-excision after BCS.
• To assess if the margin index can identify patients with a higher probability of residual disease.

Main Methods:

• Retrospective review of a prospectively maintained database of women undergoing BCS (1980-2010).
• Analysis of 246 women who underwent re-excision due to close margins.
• Comparison of average margin index between groups with and without residual disease using Student t-test and logistic regression for ROC analysis.

Main Results:

• Twenty-nine percent of patients undergoing re-excision had residual disease.
• The margin index was not a significant predictor of residual disease across various cutoff values.
• Average margin index was higher in patients without residual invasive cancer, but not for residual ductal carcinoma in situ.

Conclusions:

• Margin index was not predictive of residual cancer in women undergoing BCS for early-stage breast cancer at this institution.
• Factors like ductal carcinoma in situ and margin characteristics may limit the predictive power of the margin index.