Oncological Safety of Oncoplastic Level II Mammoplasties After Neoadjuvant Chemotherapy for Large Breast Cancers: A Matched-Cohort Analysis.

BACKGROUND

Oncoplastic surgery (OPS) has extended the indications for breast-conserving surgery (BCS). Its role in patients with large breast cancers treated with neoadjuvant chemotherapy (NAC) is unclear. This study evaluated the oncological safety of OPS for tumors with partial response after NAC.

METHODS

A consecutive series of 65 patients who underwent OPS (study group) after NAC for large breast cancer from January 2004 to July 2018 was compared with 130 matched patients treated by NAC, followed by standard BCS in 65 cases and mastectomy in 65 cases (two case-controlled groups).

RESULTS

The mean initial radiological tumor size was 46 mm. Residual pathological tumor size was 22 mm in the OPS cohort, 19 mm in the standard BCS cohort, and 31 mm in the mastectomy cohort (p > 0.05). The mean follow-up was 59 months in the study cohort. Five-year local recurrence rates were 0%, 0%, and 10.5% (0-22%) for the OPS, BCS, and mastectomy cohorts, respectively, while 5-year regional recurrence rates were 4.1% (0-11.1%), 0, and 19.4% (0-35.2%, p > 0.05), respectively. Five-year overall survival was 85.3% for the OPS cohort, 94.1% for the standard BCS cohort (p = 0.194), and 79.9% for the mastectomy cohort (p = 0.165).

CONCLUSIONS

OPS is safe after NAC for large breast cancers, and provides excellent local control, identical to that of tumors with a better response, treated by standard BCS. After NAC, OPS can be a valuable treatment option for tumors that did not shrink optimally and would not be suitable for standard BCS.