Breast conservation therapy for early breast cancer. Comparison of breast conserving surgery with or without radiotherapy

Radiation therapy (RT) following breast conserving surgery (BCS) for early breast cancer has been performed only in those patients with some unfavorable prognostic factors, i.e. young age, positive nodes, positive margins, etc at our facility. The purpose of this study was to retrospectively compare the outcomes of (BCS) with or without RT. From November 1989 to August 1998, 161 patients (163 breasts) underwent BCS in our facility. Of these, 38 patients (39 breasts) received RT to the breast (RT(+) group) and the remaining 123 patients (124 breasts) did not receive RT (RT(-) group). Patients in the RT(+) group were significantly younger and had larger tumors, more positive nodes, extensive intraductal spread and positive margins. Median follow-up period was 37 months (range 2.4-108 months). Ten patients in the RT(-) group and 1 patient in the RT(+) group developed ipsilateral breast recurrence. The 5-year ipsilateral breast recurrence rates were 9.9% in the RT(-) group and 3.4% in the RT(+) group (N.S.), and the 5-year breast conserving rates were 90.3% and 96.0% (N.S.), respectively. The five-year disease specific survival rates were 96.6% and 96.0%, respectively (N.S.). Multivariate analysis revealed that non-invasive cancers (p=0.0095), lymphatic invasion (p=0.05) and RT(-) (p=0.07) had higher ipisilateral breast recurrence rate. Severe complications related to RT have not been observed. Even though patients in the RT(+) group had more risk factors for local recurrence, both groups showed identical ipsilateral breast recurrence rates and survival rates. (author)