Extreme oncoplasty: Expanding indications for breast conservation.

Introduction: Presence of multiple lesions and/or tumor span ≥5 cm are traditional indications for mastectomy. Patient desire for breast conservation has increased the interest in extreme oncoplastic breast conserving surgery (EOBCS) to avoid mastectomy; however, perioperative outcomes in this population have not been well described.

Methods: This is an observational cohort of breast cancer patients with multiple lesions and disease span ≥5 cm who underwent EOBCS. Patient demographics, disease span, margin width, mastectomy and re-excision rates, and cosmesis were evaluated.

Results: One hundred-eleven patients underwent EOBCS between 2012 and 2017. Eighty-two patients presented with multifocal or multicentric disease with an average of 3.2 lesions per breast spanning 57.1 ± 23.6 mm. Eighteen patients presented with unifocal tumors measuring an average of 67.6 mm (range 50-160 mm) on imaging. Eleven patients with an imaging size of <5 cm had a disease span ≥5 cm on final pathology. No tumor on ink occurred in 87 (78.3%) patients. Fifty-seven (51.4%) patients had additional surgery for inadequate margins. Fifteen (12.6%) patients elected to have mastectomy while 42 (37.8%) patients opted for re-excision. Good to excellent cosmetic results were reported in 95% of patients who ultimately achieved breast conservation. Recurrence rate was 1.1% in patients who completed EOBCS and adjuvant radiation therapy.

Conclusion: EOBCS can allow for breast conservation in patients who are traditionally counseled to undergo mastectomy. Although the re-excision rate was significant, most patients ultimately achieved breast conservation with adequate margins. Further study is warranted to determine the long-term oncologic outcomes of this approach.