The Impact of Mastectomy Weight on Reconstructive Trends and Outcomes in Nipple-Sparing Mastectomy: Progressively Greater Complications with Larger Breast Size

Purpose:

            Reconstructive trends and outcomes for nipple-sparing mastectomy (NSM) continue to be defined. The graduated impact of breast size and mastectomy weight remain incompletely evaluated. We therefore examine patient-specific trends and outcomes in a large number of NSMs stratified by mastectomy weight to fully evaluate the impact of breast size on reconstructive complications and further aid in risk stratification of patients presenting for breast reconstruction after NSM.

Methods:

            All patients undergoing NSM from 2006 to June 2016 were identified. Demographics and outcomes were analyzed and stratified by mastectomy weight ≥800 grams (large group), between 799 and 400 grams (intermediate group), and <400 grams (small group).

Descriptive statistics and measures of central tendency were used to describe absolute and mean results, respectively. Student’s t-tests were used to analyze binary data sets while Chi-squared analysis was used to compare proportional responses. A binary logistic regression analysis was also performed. P-values of less than 0.05 were significant.

Results:

            Of 809 NSMs, 66 (8.2%) had mastectomy weights ≥800 grams, 328 (40.5%) had mastectomy weights between 799 and 400 grams, and 415 NSMs (51.3%) had mastectomy weights <400 grams.

            NSMs in the large group were significantly more likely to experience major mastectomy flap necrosis (p=0.0005), complete nipple-areola complex necrosis (p<0.0001), explantation (p<0.0001), cellulitis treated with oral (p=0.0008) and intravenous (p=0.0126) antibiotics, abscess (p=0.0254), and seroma (p=0.0126) compared to NSMs in the intermediate group.

            Compared to small NSMs, NSMs in the large group had greater major mastectomy flap necrosis (p<0.0001), complete (p<0.0001) and partial (p=0.0409) nipple-areola complex necrosis, explantation (p<0.0001), cellulitis treated with oral (p<0.0001) and intravenous (p<0.0001) antibiotics, abscess (p=0.0119) and seroma (p<0.0001).

            NSMs in the intermediate group were more likely to experience major (p<0.0001) and minor (p<0.0001) mastectomy flap necrosis, complete (p=0.0015) and partial (p<0.0001) nipple-areola complex necrosis, cellulitis treated with oral antibiotics (p=0.0062), and seroma (p=0.0248) compared to small NSMs.

            A logistic regression analysis examining risk for occurrence of any complication was performed. Mastectomy weight ≥800 grams (p<0.0001; Odds Ratio [OR] 5.108), mastectomy weight between 799 and 400 grams (p<0.0001; OR 2.614), immediate, permanent implant reconstruction (p=0.037; OR 1.699) and follow-up time (p=0.003; OR 0.981) were positively predictive of occurrence of any complication with immediate breast reconstruction after NSM.

Conclusions:

            Trends and outcomes in immediate NSM reconstruction are greatly influenced by mastectomy weight and breast size. Progressively greater reconstructive complications, including ischemic and infectious complications, were significantly associated with increasing mastectomy weight in NSM. With this information, risk stratification and patient selection may be further optimized as a rising number of patients present to plastic surgeons for consideration of immediate breast reconstruction after NSM.