Background: Microscopically clear lumpectomy margins are critical for optimizing local control with breast conservation for cancer. Re-excisions are often necessary to achieve clear surgical margins. Factors that contribute to nonnegative margins and necessitate re-excision may increase the risk of local recurrence.
Methods: Patients who were treated with breast conservation for breast cancers were identified from a prospective database maintained by one of the authors. Factors associated with local recurrence were evaluated in 459 consecutive patients with attention to the number of re-excisions required to obtain clear margins.
Results: Twenty-eight patients (5%) developed local recurrences at a mean follow-up of 78 months. In multivariate analysis, local recurrence was most significantly associated with the omission of radiotherapy (19% vs. 5%; relative risk [RR], 3.64; 95% confidence interval, 1.6-8.2), followed by young age (52 vs. 58; 95% confidence interval, -.83 to -10.6 years) and the number of re-excisions required to obtain clear margins (none, 4%; one, 7% [RR, 2.05; 95% confidence interval, .86-4.89]; two or more, 17% [RR, 5.20; 95% confidence interval, 1.44-18.8]). Tumor size, the number of involved nodes, pathology, and adjuvant chemotherapy were not significantly related to local recurrence.
Conclusions: The risk of local recurrence after breast conservation for breast cancer increases progressively with the number of re-excisions needed to achieve clear margins. Patients in whom the cancer is fully excised with clear margins in the first excision will have less of a chance of local recurrence compared with patients who need further re-excision to achieve clear margins.