Risk Factors for Positive Resection Margins Following Breast-Conserving Surgery

Area of Science:

• Oncology
• Radiology
• Surgical Pathology

Background:

• Margin re-excision is a critical quality measure for breast conserving surgery (BCS), with a target of less than 20% in the UK.
• Despite extensive research, factors leading to margin involvement remain, contributing to a persistently high re-excision rate.
• This study investigates adverse features compromising margin clearance in BCS for invasive breast carcinoma and ductal carcinoma in situ (DCIS).

Purpose of the Study:

• To identify adverse pathological and radiological features associated with margin re-excision in BCS.
• To evaluate the discrepancy between imaging-estimated and histopathological tumor size.
• To analyze the effectiveness of re-excision in achieving clear margins.

Main Methods:

• Retrospective analysis of 194 margin re-excisions following BCS for invasive breast carcinoma and DCIS (October 2013-September 2018).
• Inclusion of radiological (mammogram, ultrasound, MRI) and histopathology data for each patient.
• Analysis of lesion size, focality, tumor characteristics, and margin status post-re-excision.

Main Results:

• Overall re-excision rate was 14.06%.
• Ductal carcinoma in situ (DCIS) at the resection margin was the most consistent factor necessitating re-excision.
• A significant discrepancy was observed between imaging and histopathological tumor size, with mammography and ultrasound showing better correlation than MRI.

Conclusions:

• The presence of DCIS at the resection margin is the primary predictor for re-excision in BCS.
• Discrepancies in tumor size measurement between imaging modalities and final pathology impact surgical planning and outcomes.
• Mammography and ultrasound provide more accurate tumor size estimations compared to MRI in this cohort.