The Long-Term Outcomes of Partial Breast Irradiation Using External Beam after Breast Conserving Surgery

To examine long-term outcomes of a single institution’s cases of partial breast irradiation.

Between January 1990 and March 2001, a total of 104 patients with T1 or T2 breast cancer were treated with partial breast irradiation using external beam after breastconserving surgery. Ipsilateral breast tumor recurrence (IBTR) and contralateral breast tumor occurrence (CBTO) were examined. Median follow-up time was 10.2 years.

IBTR rates at 5, 10 and 15 years were 2%, 6.5% and 13.2%, respectively. CBTO rates at 5, 10 and 15 years were 0%, 1% and 5%, respectively. Failure within radiation field occurred in 1 patient and failure outside radiation field occurred in 7 patients. Of 7 recurrences outside radiation field, 1 recurred diffusely in the skin of the breast, 3 recurred in another portion of the breast and 3 recurred in the breast near the radiation field. The incidence of failure outside radiation field was high compared to that of CBTO, but this difference was not statistically significant (p=0.059).

This study speculates that PBI is a feasible alternative to WBI.

Keywords: Breast cancer, External beam irradiation, Partial breast irradiation, Recurrence, Surgery.