Impact of initial surgical margins and residual cancer upon re-excision on outcome of patients with localized breast cancer.

Background: A significant proportion of patients undergoing breast conservation therapy require additional operations to obtain clear margins. The aim of this study was to assess the impact of initial margins and residual carcinoma found on second surgery on the outcomes of breast cancer patients.

Methods: In this retrospective study, Cox proportional-hazard regression analysis was performed to evaluate data from 437 patients with stage I to IIIA breast cancer who underwent initial breast-conserving surgery between 1994 and 2004.

Results: The distant recurrence rate was higher among patients with initial positive margins than among those with initial negative margins (15.5% vs 4.9%; hazard ratio, 3.6; 95% confidence interval 1.5-8.7; P = .003). For patients who had underwent second surgery, the finding of a residual invasive carcinoma was associated with increased risk for distant recurrence (22.8% vs 6.6%; hazard ratio, 3.5; 95% confidence interval, 1.8-7.4; P = .0001).

Conclusion: Invasive residual carcinoma found during subsequent surgery after initial compromised margins is an important prognostic marker for distant recurrence.