Second conservative treatment for second ipsilateral breast tumor event: A systematic review of the different re-irradiation techniques

•For breast cancer recurrence, salvage mastectomy is challenged by 2nd conservative approach for selected patients.•For 2nd conservative treatment, a re-irradiation of the tumor bed is warranted in an adjuvant setting.•Multicatheter interstitial brachytherapy is the most popular re-irradiation technique described in the literature.•New re-irradiation procedures are investigated: Intra-operative, external beam radiation therapy, balloon based brachytherapy.•The aim of this review was to describe and report the oncological outcome and toxicity profile of the different re-irradiation techniques currently available/explored in order to save the patient from a mutilating treatment.