Perpendicular inked versus tangential shaved margins in breast-conserving surgery: does the method matter?

Area of Science:

• Oncology
• Surgical Pathology
• Breast Cancer Surgery

Background:

• Methods for assessing surgical margins and defining negative margins in breast-conserving surgery (BCS) lack standardization.
• Variability in margin assessment impacts patient outcomes and treatment decisions.

Purpose of the Study:

• To compare the incidence of positive margins and reexcision rates between perpendicular inked margins and tangential shaved margins in BCS.
• To evaluate the impact of different margin assessment techniques on surgical outcomes.

Main Methods:

• A retrospective study comparing two margin assessment protocols: perpendicular inked margins (Group A, n=263) and tangential shaved margins (Group B, n=261).
• Group A margins were classified as positive, close (defined by distance), or negative. Group B margins were reported as positive or negative.
• Data on positive margin rates and reexcision rates were analyzed for both groups.

Main Results:

• The tangential shaved margin technique (Group B) showed a significantly higher rate of reported positive margins (49%) compared to perpendicular inked margins (Group A, 16%).
• When 'close' margins in Group A were included, there was no significant difference in combined positive/close margins between techniques.
• Despite similar residual disease rates, Group B had a significantly higher reexcision rate (75%) compared to Group A's combined positive/close margins (< or =3 mm, 52%).

Conclusions:

• The tangential shaved-margin technique leads to more reported positive margins and higher reexcision rates, potentially due to reduced ability to discriminate close margins.
• Surgical judgment plays a key role in deciding on reexcision, as evidenced by varied reexcision rates even with positive or close margins.
• Further follow-up is necessary to ascertain the long-term equivalency of local recurrence rates between the two margin assessment methods.