The ongoing advancements in breast cancer screening detects more cases at earlier stages. Improved diagnostics have benefited breast cancer patients and complimented other therapy advancements by decreasing comprehensive treatment and easing the journey to remission/cure for many patients . While patients recognize the importance of oncologic safety, they also demand (and deserve) management that facilitates social, psychosocial, and sexual well-being as well as maximal aesthetic outcome and functional recovery. This prompted breast cancer surgeons to consider methods that will improve patient quality of life with complete resection of the tumor(s).
Although breast-conserving therapy is typically the first choice to treat breast cancer, there are several cases where it is not recommended. Patients with diffuse lesions or multiple lesions or patients with a small breast size (which is typical for Asian woman) will experience serious breast deformation if a breast-conserving surgery is performed . The proportion of patients receiving breast-conserving therapy is generally lower in China than in Western countries [16, 17]. However, total mastectomy is also not a desirable choice for most Chinese patients . The long, conspicuous scar and massive skin resection required by a total mastectomy negatively influences the postoperative aesthetic outcome and leads to upper extremity dysfunction that affects the patient’s quality of life . Due to sparing NAC and avoiding excessive skin resection, open NSM improved breast appearance after total mastectomy. Unfortunately, it has a high probability of NAC ischemia and necrosis  and an obvious scar in the chest wall. Therefore, it does not completely meet the aesthetic demand of patients.
Endoscopy-assisted NSM is often used to improve the postoperative aesthetic outcome. In our study, we introduced SIE-NSM in which two operations (axillary lymph node staging and mammary gland resection) were completed via a small, inconspicuous single-port incision in the axillary fossa, and a sufficient operation space was created by utilizing the insufflation method.
This study showed that there was no statistical difference in the local recurrence rate between the SIE-NSM group and C-OM group. However, we also observed a smaller tumor size and a lower age of patients in the SIE-NSM group. Therefore, we conducted multivariable binary logistic regression analysis using tumor size and age as covariates to assess the risk of local recurrence, and no statistically significant difference was found. This observation requires further prolonged follow-up and will be validated by an ongoing randomized controlled clinical trial (NCT04461847) of SIE-NSM vs C-OM conducted by our center.
We evaluated the aesthetic outcome and psychosocial well-being after operation with the BREAST-Q. Scores in the SIE-NSM group were all significantly better than those in the C-OM group. To adjust for age and BMI, multivariable linear regression model analysis was performed, and the SIE-NSM group still had significantly superior scores. We hypothesize several explanations for an increase in satisfaction with breasts and chest well-being: (1) a significantly shorter incision in the SIE-NSM; (2) no visible surgical scar on the chest because the single-port incision was hidden in the axillary fossa (Fig. 6); (3) SIE-NSM spared the NAC; and (4) due to small breast size, the loss of the mammary gland yet the sparing of the NAC only affected the symmetry of the breasts slightly. The significant improvement in satisfaction with breasts and chest well-being impacted the psychosocial well-being and sexual well-being in SIE-NSM group. This suggests that SIE-NSM improves the postoperative aesthetic outcome while also improving the psychosocial well-being and quality of life.
Upper extremity function is also an important factor influencing quality of life after mastectomy. C-OM requires the resection of a massive amount of chest skin and limits of movement of the upper extremity. Patients in the SIE-NSM group had less chest wall/breast pain, had a better range of motion in the shoulder, and had significantly superior use of their arms in daily life compared to the C-OM group. Because the patients in the SIE-NSM group were generally younger, a multivariable linear regression model analysis after adjusting for age was conducted. The results were similar. This indicated that SIE-NSM reduced the traction of the chest wall scar to the upper extremity by preserving the integrity of the chest skin. Therefore, this improved upper extremity function and quality of life.
NAC ischemia and necrosis are common and serious complications after open NSM, and the highest incidence rate of ischemia was 64.1% . NSM with an incision on the breast surface can damage the skin and subcutaneous vasculature of the breast, while the areolar incision can directly damage the NAC blood supply and lead to a high incidence rate of NAC ischemia and necrosis . A recent study has shown that endoscopic NSM with an axillary incision can significantly decrease the incidence rate of NAC ischemia and necrosis . In this study, only three SIE-NSM patients (4.2%) developed grade 1–3 NAC ischemia. No grade 4 or 5 (severe) NAC ischemia or necrosis was observed likely due to the incision in the axillary fossa, the deep nipple mammary duct was excised by laparoscopic scissors (reduced deep thermal damage caused by a harmonic scalpel or electrocautery), and the blood supply of the NAC and skin flap was assessed by ICG angiography before the operation [23, 24]. The blood supply to the NAC is classified by where the perfusion originates. Type V1 originates predominantly from the underlying breast tissue (Fig. 7A), type V2 originates from the surrounding skin (Fig. 7B), and type V3 is a combination of V1 and V2 (Fig. 7C). For type V1, when the mammary gland resection occurs, the vertical blood supply will be completely damaged, and ischemia and necrosis happen easily. The three patients with NAC ischemia had type V1. For these patients we avoided compression dressings and used nitroglycerin ointment because Gdalevitch et al  found that the use of nitroglycerin ointment could improve the blood supply to the skin flap and reduce necrosis in patients undergoing NSM and immediate reconstruction.
Subcutaneous effusion is a common complication after total mastectomy and can significantly influence the rehabilitation process. We observed that the incidence rate of subcutaneous effusion was 10.7% in the C-OM group and 0% in the SIE-NSM group. This observation can be explained by the following possible causes: (1) the heat from the electrotome used to dissect the skin flap in C-OM resulted in fat liquidation, which increased the risk of subcutaneous effusion. The dissection of the skin flap in SIE-NSM was performed with laparoscopic scissors, which reduced the production of subcutaneous effusion; (2) liposuction during SIE-NSM greatly decreased the fat content in the breast and reduced the occurrence of fat liquidation; and (3) after liposuction, the endoscopic amplification clearly displayed the membrane anatomy and ligaments around the mammary gland , which avoided damage to the membrane anatomy and reduced subcutaneous effusion.
In this study, blood loss was significantly lower in the SIE-NSM group compared to the C-OM group. This was due to the clear visualization of the membrane anatomy surrounding the mammary gland in SIE-NSM. The dissection was performed between the membrane anatomical structures, which reduced bleeding. Furthermore, the tumescent solution used preoperatively contained epinephrine, which could constrict the blood vessels and reduce blood loss. The operative time in the SIE-NSM group was longer than that in the C-OM group, likely due to the requirement of precise technique, which lengthens the operation time. The liposuction required to establish the operation space and expose the membrane anatomy lengthened the time as well.