P108. Extreme oncoplastic conservation is a safe new alternative to mastectomy

Abstract Objectives Extreme oncoplastic breast conserving surgery (eOPBCS) allows breast conservation for tumours ≥ 50 mm, but long-term outcomes are unclear. We investigated early complications and the longer-term clinical and oncological outcomes following eOPBCS to assess the clinical utility and safety of this technique. Materials and methods A prospectively collected database of all eOPBCS procedures (1993–2016) using LD miniflaps (LDm) and therapeutic mammoplasties (TM) was interrogated and cross-checked with hospital records to establish length of follow up (FU), clinical outcomes (complications, revisions), local recurrence (LR) and survival. Results Ninety eOPBCS procedures (62 LDm, 28 TM) performed for large tumours (mean 67 [50–177] mm) were identified, overall FU 80 (10–308) months (LDm 91 [13–308], TM 54 [10–120] months). Forty two per cent were node positive, and 2 were benign (benign cases excluded from LR and FU analysis). Eleven patients required surgery for involved excision margins (LDm 3 re-excisions and 2 mastectomies, TM 6 mastectomies). Surgery for complications and subsequent revision was required in 6% and 37% of LDm and 18% and 7% of TM patients, respectively. Seven patients developed LR (LDm 5 versus TM 2) giving a predicted 5 and 10 year LR rate of 1.1% and 16%. Conclusion Long-term FU of this unique series has confirmed that eOPBCS is a safe procedure for patients with bulky tumours normally treated by mastectomy, without risking local control. TM patients experienced more early complications but LDm patients required more revisions over a more prolonged period of FU.