Long-term results of multicatheter interstitial high-dose-rate brachytherapy for accelerated partial-breast irradiation.

PURPOSE: The purpose of this study was to report the long-term results of women treated in one center with accelerated partial-breast irradiation (APBI) with interstitial high-dose-rate (HDR) brachytherapy.

MATERIALS AND METHODS: We analyzed data from women treated in one center with adjuvant interstitial HDR brachytherapy for early-stage breast cancer. Treatment regimen was homogeneous for all women with treatment dose 32Gy in 8 fractions twice daily given to the tumor bed with interstitial HDR brachytherapy.

RESULTS: About 364 women were treated with interstitial HDR brachytherapy as APBI from March 2000 to March 2014. Mean age at diagnosis was 62 years. Stage distribution was as follows: T1a = 12%, T1b = 33%, T1c = 40%, T2 = 14%, and Tis = 1%. 97% of patients were N0. 88% had invasive ductal carcinoma. 86% had positive hormone receptor status. 14 ipsilateral breast tumor recurrences were identified with 12 deemed local recurrences and 2 deemed to be second ipsilateral primaries. Actuarial 5-year and 10-year overall survival rates were 95.1% and 92.2%, respectively. Actuarial 5-year and 10-year local relapse-free survival rates were 96.2% and 88.8%, respectively.

CONCLUSIONS: The results of this previously unreported series of women treated with a homogeneous APBI method exclusively with interstitial HDR brachytherapy present further data justifying that in appropriately selected women, APBI with interstitial brachytherapy provides rates of local control and survival comparable with whole-breast irradiation.