Repeat Breast-Conserving Surgery for Ipsilateral Breast Tumour Recurrence: Towards a Paradigm Shift - A Narrative Review

Background and Objective: Ipsilateral breast tumour recurrence (IBTR) following breast-conserving therapy has traditionally been managed with salvage mastectomy because of concerns regarding oncological safety and toxicity associated with repeat breast conservation and re-irradiation. However, accumulating evidence from retrospective series, meta-analyses, prospective cohort studies, and phase II trials has challenged this longstanding paradigm. This perspective evaluates the evidence supporting repeat breast-conserving treatment (rBCT) as an alternative to salvage mastectomy in selected patients with IBTR.

Methods: A targeted narrative review of published literature was conducted, encompassing meta-analyses, prospective cohort studies, population-based analyses, phase II trials, and relevant international clinical practice guidelines addressing the management of IBTR following breast-conserving therapy. Studies were selected on the basis of clinical relevance, methodological quality, and influence on contemporary practice.

Key Content and Findings: Two independent meta-analyses, prospective cohort data from the GEC-ESTRO multicentre study, and two landmark phase II trials (NRG Oncology/RTOG 1014 and RE-IORT) collectively demonstrate that rBCT — defined as repeat breast-conserving surgery (rBCS) combined with adjuvant partial breast re-irradiation (APBI) — achieves local control and overall survival comparable to salvage mastectomy in carefully selected patients. Re-irradiation is an oncological prerequisite; its omission is associated with a two- to fourfold increase in second local recurrence. Axillary management is evolving towards de-escalation via repeat sentinel lymph node biopsy and targeted axillary dissection. Patient selection, tumour biology, and multidisciplinary planning are central to safe implementation.

Conclusions: rBCT represents a clinically valid alternative to salvage mastectomy in carefully selected patients with IBTR, supported by consistent evidence across meta-analyses and prospective trials. Randomised controlled trial data are lacking; ongoing trials (BREAST, REPEAT, BRASIL) are expected to provide the level I evidence required to inform formal guideline revision. rBCT should be routinely offered and discussed at MDT level in eligible patients.