Single fraction boost with high dose rate interstitial brachytherapy in conservative treatment of breast carcinoma

We evaluated the effectiveness of interstitial high dose rate brachytherapy as a single fraction boost to the surgical bed in patients with breast cancer undergoing conservative treatment. The comparison was with the alternative of electron boost. Between April 1999 and December 2000, we conducted a prospective study of 84 patients with infiltrative breast carcinoma treated with conservative surgery, with free margins. This was followed by external radiotherapy to the breast of up to 46 Gy and one application of brachytherapy with needles inserted into the surgical bed, and administering 7 Gy to 90% with high dose rate (HDR). With a mean follow-up of 43 months, only one patient had therapeutic failure in the implant area, and local control was 98.5%. Another patient had a 2nd tumour in a different quadrant and 3 developed metastasis. Survival at 5 years was 98.7%. Acute toxicity was minimal, with excellent or good cosmetic appearance in 95%. Brachytherapy with high dose rate as single fraction boost in conservative treatment of breast carcinoma is simple, fast, well tolerated, with excellent local control, good cosmetic appearance, and with minimal late-onset toxicity.