Purpose: To initiate fractionated, interstitial high dose rate brachytherapy of the tumour bed as the sole radiation modality after breast conserving surgery.
Patients and methods: In 41 cases of selected stage I-II breast cancer the tumour bed was marked with titanium clips during breast conserving surgery. The tumour bed was implanted with flexible plastic catheters to deliver postoperative radiotherapy. In 8 cases 7 x 4.33 Gy (30.3 Gy), in 33 cases 7 x 5.2 Gy (36.4 Gy) interstitial 192Ir high dose rate brachytherapy was given to the clipped area. Irradiation of the whole conserved breast was omitted. The radiation side effects were assessed by mammograms and MRI-examinations.
Results: At a median follow up of 17 (4-36) months neither distant nor regional failure was observed. Local recurrence was detected in 1/41 (2.4%) case. G2 radiation side effects were observed in 2/21 (9.5%).
Conclusions: Postoperative sole brachytherapy of the tumour bed with careful patient selection and adequate quality assurance seems to be a feasible alternative to whole breast teletherapy. Sole brachytherapy shortens the time of radiotherapy from 5-6 weeks to 5 days, and reduces the costs of treatment. The skin and volume sparing effect of interstitial irradiation may decrease the side effects of radiotherapy.