Accelerated treatment of breast cancer

Purpose: Radiation therapy (RT) restricted to the tumor bed, by means of an interstitial implant, and lasting 4 to 5 days after lumpectomy was prospec tively evaluated in early-stage breast cancer patients treated with breast- conserving therapy (BCT). The goals of the study were to determine whether treatment time can be reduced and whether elective treatment of the entire breast is necessary. Materials and Methods: Between January 1993 and January 2000, 174 cases of early-stage breast cancer were managed with lumpectomy followed by RT restr icted to the tumor bed using an interstitial implant. Each brachytherapy pa tient was matched with one external beam RT (ERT) patient derived from a re ference group of 1,388 patients treated with standard BCT. Patients were ma tched for age, tumor size, histology, margins of excision, absence of an ex tensive intraductal component, nodal status, estrogen receptor status, and tamoxifen use. Median follow-up for both the ERT and brachytherapy groups w as 36 months. Results: No statistically significant differences were noted in the 5-year actuarial rates of ipsilateral breast treatment failure or locoregional fai lure between ERT and brachytherapy patients (1% v 0%, P = .31 and 2% v 1%, P = .63, respectively). In addition, there were no statistically significan t differences noted in rates of distant metastasis (6% v 3%, P = .24), dise ase-free survival (87% v 91%, P = .55), overall survival (90% v 93%, P = .6 6), or cause-specific survival (97% v 99%, P = .28). Conclusion: Accelerated treatment of breast cancer using an interstitial im plant to deliver radiation to the tumor bed alone over 4 to 5 days seems to produce 5-year results equivalent to those achieved with conventional ERT. Extended follow-up will be required to determine the long-term efficacy of this treatment approach. (C) 2001 by American Society of Clinical Oncology .