Prognostic factors after conservative surgery and radiation therapy for early stage breast cancer

A retrospective review was conducted of all early-stage breast cancer patients treated with breast-conservation surgery plus radiation therapy (BCS/RT) to determine mortality and recurrence rates and to evaluate prognostic factors for these outcomes. Between 1982 and 1988, 121 patients with stages I and II breast cancer were treated with BCS/RT at our institution. Most of the patients (83%) had re-excision of the initial biopsy site and at final surgical evaluation, only 4 patients had positive margins (3.2%). Median follow-up was 89.7 months. Cox proportional hazards regression models were used to select prognostic factors significant for breast cancer-specific mortality, overall disease recurrence, and local recurrence. Breast cancer survival rates were 92% at 5 years and 83% at 10 years. Prognostic factors predicting breast cancer mortality included positive lymph nodes (relative risk=.9; 95% confidence interval, 1.2,12.2) and a higher grade (relative risk=1.9; 95% confidence interval, 1.1,3.3). For disease recurrence, prognostic factors included positive nodes (relative risk=2.6; 95% confidence interval, 1.2, 5.5), and a negative progesterone-receptor status (relative risk=0.3; 95% confidence interval, 0.2, 0.8). Local recurrence rates were 2.5% at 5 years and 14% at 10 years. No prognostic factors were significant for local recurrence; however, most patients had negative margins after surgery.