The oncological safety of nipple-sparing mastectomy - a Swedish matched cohort study

The oncological safety of nipple-sparing mastectomy in the context of immediate breast reconstruction is debatable. Previous studies report wide variations in local recurrence rates and randomised or matched cohort study designs are lacking. The aim of this study is to compare the local recurrence rate after nipple-sparing mastectomy to that after conventional mastectomy. Further, to compare the disease-free, overall and breast cancer-specific survival rates.

A retrospective review of all patients undergoing nipple-sparing mastectomy with immediate implant-based breast reconstruction at Karolinska University Hospital, Sweden, in the years 2000-2012 was conducted. These were matched 1:3 to patients operated by conventional mastectomy. Matching variables were age, tumour stage and year of surgery.

Sixty-nine nipple-sparing mastectomies in 67 patients (study group) and 206 conventional mastectomies in 203 patients (control group) were included in the study. Median follow-up was 36 and 35 months for the study and control group, respectively. No local recurrence occurred in the study group, while seven local recurrences were observed in the control group (p = 0.197). The estimated 5-year figures were 100% and 95.8% (local recurrence-free survival), 94.1% and 82.5% (disease-free survival), 96.2% and 91.3% (overall survival) and 98.0% versus 94.8% (breast cancer-specific survival). Survival rates did not differ significantly between groups.

Nipple-sparing mastectomy may be offered to selected breast cancer patients without any negative impact on oncological safety.