Positive surgical margins and ipsilateral breast tumor recurrence predict disease-specific survival after breast-conserving therapy

BACKGROUND. The current study identified determinants of systemic recurrence and disease-specific survival (DSS) in patients with early-stage breast carcinoma treated with breast-conserving surgery and radiation therapy (breast-conserving therapy, or BCT). METHODS. The study population consisted of 1,043 consecutive women with Stages I of II breast carcinoma who underwent BCT between 1970 and 1994. Clinical and pathologic characteristics evaluated included age, tumor size, tumor grade, estrogen and progesterone receptor status, surgical margins, axillary lymph node involvement, and use of adjuvant therapy. RESULTS. At a median follow-up time of 8.4 years, 127 patients (12%) had developed an ipsilateral breast tumor recurrence (IBTR), and 184 patients (18%) had developed a systemic recurrence. On multivariate logistic regression analysis, tumor size greater than 2 cm, positive lymph nodes, lack of adjuvant tamoxifen therapy, and positive margins (odds ratio [OR], 3.7; 95% confidence interval [CI], 1.1-12.3; P = 0.034) were predictors of systemic recurrence. When IBTR was added into the model, adjuvant therapy and surgical margins were not independent predictors; however, IBTR was an independent predictor of systemic recurrence (IBTR vs. no IBTR; OR, 6.2; 95% CI, 3.1-12.3; P < 0.001). The 10 year DSS rate after BCT was 87%. On multivariate Cox proportional hazards model analysis, the following factors were independent predictors of poor DSS: tumor size greater than 2 cm (vs. ≤ 2 cm; relative risk [RR], 2.3; 95% CI, 1.2-4.3; P = 0.010), negative progesterone receptor status (vs. positive; RR, 2.7; 95% CI, 1.4-5.1; P = 0.003), positive margins (vs. negative; RR, 3.9; 95% CI, 1.4-11.5; P = 0.011), and IBTR (vs. no IBTR; RR, 5.5; 95% CI, 2.8-11.0; P < 0.001). CONCLUSIONS. Positive surgical margins and IBTR are predictors of systemic recurrence and disease-specific survival after BCT. Aggressive local therapy is necessary to ensure adequate surgical margins and to minimize IBTR.