Margin status and local recurrence after breast-conserving surgery.

Objective: To examine the effect of microscopic tumor at the margins on local recurrence after breast-conserving surgery for invasive carcinoma.

Design: Retrospective review of patients treated with surgical resection followed by radiation therapy.

Setting: A university-based radiation department and a community-based cancer referral center.

Patients: A consecutive series of 272 women treated between 1982 and 1990.

Main Outcome Measure: Local recurrence according to the histopathologic status of excised margins and the total dose of radiation.

Results: During a mean follow-up period of 48 months, the overall rate of local recurrence was 6.3%. Local recurrence was more frequent (P = .0001) in patients with histologically positive margins (18.2%) than in those with unknown margins (7.1%) or negative margins (3.7%). In the 44 patients with positive margins, the local recurrence rate was 8.3% after radiation doses of 66 Gy or more compared with 21.9% following lower doses.

Conclusions: Microscopic involvement of resection margins increases the risk of local recurrence following breast-conserving surgery for invasive carcinoma. Therefore, every effort should be made to achieve negative margins intraoperatively.