The Effect of Wire Versus Magnetic Seed Localization on Lumpectomy Cavity Size

Area of Science:

• Oncology
• Radiology
• Surgical Techniques

Background:

• Breast-conserving surgery (BCS) is a standard treatment for breast cancer.
• Accurate lumpectomy cavity size is crucial for effective radiation therapy planning.
• Surgical localization techniques guide tumor excision and can influence cavity dimensions.

Purpose of the Study:

• To determine if surgical localization technique (wire vs. magnetic seed) affects lumpectomy cavity size on computed tomography (CT) scans.
• To assess the impact of localization technique on radiation therapy planning parameters.

Main Methods:

• Retrospective review of 387 women undergoing BCS with wire or magnetic seed localization from 2018-2021.
• Propensity score analysis with overlap weights to adjust for confounding factors.
• Primary outcome: lumpectomy cavity size on simulation CT; Secondary outcomes: margin status, pathologic volume, boost delivery.

Main Results:

• No significant difference in lumpectomy cavity size on CT scans between wire and magnetic seed localization (P=.35).
• Localization technique did not impact total pathologic volume (P=.08) or positive margins (P=.79).
• Rates of second surgeries and boost delivery were similar between groups.

Conclusions:

• Surgical localization technique does not significantly influence lumpectomy cavity size for radiation therapy planning.
• The choice between wire and magnetic seed localization does not appear to compromise radiation therapy boost delivery in BCS.