Minimally Invasive Nipple-Sparing Mastectomy Can Be Done but Should It?

The cosmetic options for mastectomy have progressed over time with the nipple-sparing mastectomy (NSM) becoming the preferred approach for suitable patients who are being treated for breast cancer or for breast cancer risk reduction.¹ NSM has been established as an oncologically safe procedure with increasing patient eligibility.¹ Farr et al² recently published a case series from the United States of 20 patients who underwent bilateral single-port robotic NSM by a single surgeon for breast cancer risk reduction or early-stage breast cancer, concluding that the procedure was feasible and safe.

Most recently, Kim et al³ performed a retrospective multicenter cohort study of 1583 patients with breast cancer who underwent NSM at 21 university hospitals in Korea from 2018 to 2020. The authors compared a minimally invasive approach (M-NSM) vs a conventional approach (C-NSM) and found no significant difference between the 2 groups regarding acute (<30 days) and chronic (<90 days) postoperative complications within the first 3 months after surgery. Wound infections were more common after M-NSM while nipple-areolar complex necrosis and postoperative seroma were more common after C-NSM. The authors concluded that an M-NSM approach was as equally safe as C-NSM.³

Based upon this study and others, there appear to be similar postoperative complication rates between M-NSM and C-NSM,⁴ thus supporting the safety of an M-NSM approach. However, 2 critical questions remain to be answered in pursuing M-NSM: (1) how much residual breast tissue (RBT) remains after M-NSM and (2) what are the long-term oncologic outcomes in both the breast cancer risk reduction and treatment settings? RBT after C-NSM and skin-sparing mastectomies ranges from 21% to 51%.⁵ Recent data suggest RBT may be lower in M-CSM (13%)⁶; however, their cohort was limited to 54 cases, limiting its comparability. Additionally, Farr et al² identified nipple-areolar complex sensation was preserved in 65% of patients, which raises the concern of RBT in these cases, which could then potentially impact future oncologic outcomes.

In 2019 the US Food and Drug Administration issued a warning that the use of robotically assisted devices for mastectomy has not been granted marketing authorization due to a lack of evidence for safety and effectiveness.⁷ While the data presented here are promising from a complication stand-point, it should not be viewed as practice changing given the study’s retrospective design and heterogeneity in surgical technique. While we await the results of prospective clinical trial data performed in a highly controlled setting (NCT05720039) that will answer these fundamental questions around M-NSM, surgeons should view this data with caution.