Outcome after mastectomy for ipsilateral breast tumor recurrence after breast conserving surgery

Ipsilateral breast tumor recurrence (IBTR) is a risk after breast conserving surgery, and is traditionally treated with mastectomy. Given the limited literature on outcome after mastectomy for IBTR, we evaluated our long-term data for this group. A retrospective review was conducted using a database of 2101 breast cancer patients at a single institution. Fifty-nine patients underwent breast conserving surgery and experienced an IBTR. Exclusion criteria included repeat lumpectomy or metastatic disease before mastectomy. Patients presented with invasive ductal (58%), invasive lobular (7%), other invasive (11%), or ductal carcinoma in situ (24%). Initial tumors were Tis (24%), T1 (42%), T2 (20%), T3 (2%), or not recorded (12%). IBTR lesions were Tis (20%), T1 (46%), T2 (25%), or T3 (9%). Median follow-up after mastectomy was 4.6 years. Thirteen patients (22%) had post-mastectomy recurrence (PMR), which decreased overall survival (P = 0.002). PMR was more common with larger IBTR tumors (P = 0.03), specifically IBTR ≥ T2 (P = 0.003). Eighty-five per cent of PMR occurred within 2 years of mastectomy. Mastectomy for IBTR remains effective treatment for most patients, but the risk of PMR remains. Patients with IBTR tumors >2 cm have an increased risk of PMR. Strict follow-up should be routine, especially during the first 24 months.