Does Localization Technique Matter for Non-palpable Breast Cancers?

Background: There are several techniques for localization of non-palpable breast tumors, but comparisons of these techniques in terms of margin positivity and volume of tissue resected are lacking.
Methods: Between 2011-2013 and 2016-2018, 2 randomized controlled trials involving 10 centers across the United States accrued 631 patients with stage 0-3 breast cancer, all of whom underwent breast conserving surgery. Of these, 522 had residual non-palpable tumors for which localization was required. The localization technique was left to the discretion of the individual surgeon. We compared margin positivity and volume of tissue resected between various localization techniques.
Results: The majority of the patients (n = 465; 89.1%) had wire localization (WL), 50 (9.6%) had radioactive seed (RS) localization, and 7 (1.3%) had Savi Scout (SS) localization. On bivariate analysis, there was no difference in terms of margin positivity (37.8% vs. 28.0% vs. 28.6%, P = .339) nor re-excision rates (13.3% vs. 12.0% vs. 14.3%, P = .961) for the WL, RS, and SS groups, respectively. Further, the volume of tissue removed was not significantly different between the 3 groups (71.9 cm ³ vs. 55.8 cm ³ vs. 86.6 cm ³ for the WL, RS, and SS groups, respectively, P = .340). On multivariate analysis, margin status was affected by tumor size (OR = 1.336; 95% CI: 1.148-1.554, P <.001) but not by type of localization ( P = .670).
Conclusions: While there are a number of methods for tumor localization, choice of technique does not seem to influence volume of tissue resected nor margin status.