Long-term outcomes after breast conservation therapy for early stage breast cancer in a community setting

Abstract

We, as a large community practice, retrospectively reviewed our experience in treating early stage breast cancer to determine rates of breast-conserving therapy (BCT), disease outcomes after such treatment, and risk factors for local recurrence. A hospital tumor registry was used to identify breast cancer cases diagnosed between 1987 and 2003. Rates of BCT and radiotherapy were examined using primary treatment data. For subsequent disease outcomes analyses, cases were limited to only those treated between 1987 and 1994 to allow for adequate follow-up. For the subset of 521 T1-2N0 patients treated with BCT, we calculated crude rates of first failure at 8 years, with outcomes classified as local failure (LF), distant or regional node failure (DNF), dead without failure (DWF), or alive without failure (AWF). Polychotomous logistic regression was done to assess the influence of age at diagnosis, tumor grade, total radiation dose to the tumor bed, and use of systemic therapy. From 1987 to 2003, rates of BCT went from 69% to 89% and the rate of radiation after breast-conserving surgery was 90%. For the subset of 521 T1-2N0 patients treated with BCT who had at least 8 years of follow-up, median age was 58 years, 15% had grade 1 tumors, 83% had T1 tumors, 4.6% had positive margins, 83% got a total radiation dose >or=60 Gy to the tumor bed, and 51% had systemic therapy. At 8 years, 7% of patients had LF, 8% DNF, 10% were DWF, and 75% were AWF. Patient age (p = 0.076), tumor grade (p = 0.056), use of systemic therapy (p = 0.077), and radiation dose (p = 0.127) had borderline significant effects on the risk of LF versus AWF. The majority of patients in this community were treated with BCT and most received radiotherapy. Local control was excellent and comparable to that seen in large academic centers.