[Second conservative radiosurgical treatment for ipsilateral breast cancer recurrence]

Purpose: Currently, radical mastectomy represents the gold standard for ipsilateral breast cancer recurrence. However, we already showed that a second conservative treatment was feasible combining lumpectomy plus low-dose rate interstitial brachytherapy. In this study, we reported the preliminary results of a second conservative treatment using a high-dose rate brachytherapy.

Patients and methods: From June 2005 to July 2009, 42 patients presenting with an ipsilateral breast cancer recurrence underwent a second conservative treatment. Plastic tubes were implanted intra-operatively at the time of the lumpectomy. After a post-implant CT scan, a total dose of 34 Gy in 10 fractions over 5 consecutive days was delivered through an ambulatory procedure. The toxicity evaluation used the Common Terminology Criteria for Adverse Events v3.0.

Results: The median follow-up was 21 months (6-50 months), median age at the time of the local recurrence was 65 years (30-85 years). The median delay between the primary and the recurrence was 11 years (1-35 years). The location of the recurrence was in the tumor bed for 22 patients (52.4%), in the same quadrant for 14 patients (33.3%) and unknown for six patients (14.3%). The median tumor size of the recurrence was 12 mm (2-30 mm). The median number of plastic tubes and plans were nine (5-12) and two (1-3) respectively. The median CTV was 68 cm(3) (31.2-146 cm(3)). The rate of second local control was 97%. Twenty-two patients (60%) experienced complications. The most frequent side effect consisted in cutaneous and sub-cutaneous fibrosis (72% of all the observed complications).

Conclusion: A second conservative treatment for ipsilateral breast cancer recurrence using high-dose rate brachytherapy appears feasible leading to encouraging results in terms of second local control with an acceptable toxicity. Considering that a non-inferiority randomized trial comparing mastectomy versus second conservative treatment could be difficult to perform, what proof level will be necessary to achieve in order to change the medical procedures?