Abstract
Aim of this study is to show that ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery can be reduced by proper surgery and modern radiotherapy techniques. Three hundred and seventy eight women with stage I or II breast cancer had breast conserving surgery and received 51โ56.1 Gy of postoperative radiation to the whole breast in 1.7 Gy fractions, but patients received different boost strategies. Group 1 (n = 188) received electron boost radiation of 12 Gy subsequent to the irradiation to the whole breast, group 2 (n = 190) received intraoperative electron boost radiation of 9 Gy directly to the tumor bed, followed by whole breast irradiation. After a median follow up period of 81.0 months in group 1 and a median follow up period of 51.1 months in group 2, 12 IBTRs (6.4%) could be observed in group 1 and no IBTR could be observed in group 2 (0.0%). The 5โyear actuarial rates of IBTR were 4.3% (95% CI, 1.9โ8.3%) and 0.0% (95% CI, 0.0โ1.9%), respectively (p = 0.0018). The 5โyear actuarial rates of distant recurrence were 8.6% (95% CI, 4.9โ13.5%) and 4.2% (95% CI, 1.8โ8.2%), respectively (p = 0.08). The 5 year diseaseโfree survival rates were 90.9% (95% CI, 85.8โ94.7%) in group 1 and 95.8% (95% CI, 91.8โ98.2%) in group 2 (p = 0.064). Immediate IORTโboost and whole breast irradiation yields excellent local control at 5 years, and was associated with a statistically significant decreased rate of IBTR compared with a similar cohort of patients treated with whole breast irradiation and conventional electron boost. ยฉ 2005 WileyโLiss, Inc.