Nipple Skin-Sparing Mastectomy

Introduction

The radicality of mastectomy for breast cancer treatment has decreased over time, from Halsted’s radical mastectomy, which was standard of care until the 1960s, to Patey’s modified radical mastectomy that avoided the excision of the pectoralis muscle, based on his studies on the relationship of lymphatic drainage of the breast to the pectoralis major. At the end of the 20th century, Toth and Lappert described the procedure of mastectomy with the minimum amount of skin excision with immediate breast reconstruction to improve the final aesthetic result of the breast. At this time, the nipple-areola complex (NAC) was also excised along with previous scars. One of the main concerns was the likelihood that the NAC would contain occult tumor cells. This concern was based on studies reporting occult NAC involvement in around 5% to 12% of cases, although the figure could be as high as 50%. A meta-analysis published in 2010 comparing skin-sparing mastectomy to conventional mastectomy showed no difference in local recurrence (LRR) between the two procedures. Another meta-analysis comparing nipple skin-sparing mastectomies (NSMs) versus SSM showed no differences in LRR or overall survival.

One significant advantage of the NSM technique is the removal of the whole breast tissue as a radical surgical procedure while preserving native breast integrity, the skin of the NAC, as well as the submammary fold, therefore improving cosmetic outcomes. Subcutaneous mastectomy differs from NSM in that, in the latter, all breast tissue is removed and the retroareolar tissue is submitted separately for histologic evaluation. Even though the majority of the breast tissue is removed, some studies have shown that removing the maximum amount of breast tissue is a major surgical challenge. In the SKINI trial, the radicality of SSM and NSM was assessed by quantifying histologically detected residual breast tissue and residual disease. Residual breast tissue was common after SSM and NSM, and the study showed that surgeon expertise was an independent factor.

The increased esthetic outcomes and quality of life (QoL) after NSM and immediate reconstruction have moved surgeons to adopt this technique in selected patients instead of SSM. Patients generally report low satisfaction with a reconstructed nipple, and psychosocial well-being and sexual well-being are lower in SSM compared to NSM.

Indications

Indications for NSM have broadened over time. Initially, indications for NSM were limited because of the fear of leaving breast tissue in the retroareolar area and, consequently, increasing local recurrence. These initial indications were based on factors that were predictors of cancer involvement in the nipple and in those patients with an increased risk of complications from the NAC-sparing procedure. They included small tumors <2 cm, favorable characteristics, no positive nodes, and no prior breast surgery.

Over time, as teams have gained experience, patient factors initially felt to contraindicate NSM have been reconsidered. Now, it is used in patients with locally advanced breast cancer, any tumor size, no clinical or imaging evidence of NAC involvement or skin involvement, good responders after neoadjuvant therapy, or patients with previous/postradiation, high body mass index (BMI), or large breast size.

Contraindications

There are clearly some contraindications to preserving the NAC, and these are related to the initial affected nipple, as in the case of Paget’s disease of the nipple and/or malignant nipple discharge, and inflammatory breast cancer.

In those patients with ductal carcinoma in situ (DCIS) who are not candidates for breast conservative surgery w/wo oncoplastic surgery, NSM is a feasible option. Special attention needs to be paid to microcalcifications close to the subareolar region and to the superficial margin, as positive margins may require additional radiation therapy that can compromise aesthetic outcomes and decrease patient satisfaction. Appropriate patient selection is crucial for the success of the technique and to minimize complications.

In women with an elevated lifetime risk of breast cancer, whether BRCA mutation carriers ( Fig. 43.1 ) or with a lifetime risk >20%, bilateral risk reduction NSM seems to be safe. Previously, Hartmann and colleagues reported data on BRCA mutation carriers, and after 13.4 years’ median follow-up no BRCA carriers developed breast cancer. At that time the risk reduction mastectomy was performed as a subcutaneous mastectomy, where no retroareolar tissue was differentially excised. Nowadays, several studies have shown that NSM is an appropriate strategy for high-risk patients. Along with a significant reduction in breast cancer, in the majority of the studies with a median follow-up of 26 to 56 months, breast cancer did not develop in any patients undergoing bilateral risk-reducing NSM.

Surgical Technique

Careful selection of patients is the first step for a successful procedure. The NSM procedure has slight variations in every single case, based on patient and oncologic factors. There is evidence that more experience is associated with fewer complications. A team learning curve for the procedure is required. Surgeons starting to perform the technique should choose patients with the least risk of complications. The surgeon should assess BMI, ptosis, breast size and shape, and whether it is a therapeutic (tumor location) or a risk-reducing NSM. Determining the optimal approach and reconstructive options requires ongoing collaboration with the reconstructive plastic surgery team.

Preoperative breast imaging is crucial to evaluate the extent of the disease. Bilateral mammograms and breast and axillary ultrasound are necessary. Magnetic resonance imaging may help in some circumstances in addition to the physical examination to assess nipple invasion. In the first reports of the technique, NSMs were performed in tumors >2 cm from the nipple, although as surgeon expertise increases negative tumor margins at the NAC can be achieved even with tumors <2 cm from the nipple, as long as they are not invading the NAC.

Reviewing breast imaging before starting the procedure will give an idea of the mastectomy flap thickness. Flap thickness varies between patients; however, it is important to perform the dissection following the avascular plane between the gland and the subcutaneous adipose tissue along the superficial fascia.

Several methods of flap dissection have been described. It can be performed with sharp dissection or with electrocautery or other types of blades (i.e., plasma). While some studies have reported differences between sharp and electrocautery dissection, in other studies, no differences in terms of necrosis or infection regardless of the method used have been reported. Other techniques that includes the use of cervical dilators have been reported to have low rates of complications.

Another important step is dissection of the retroareolar tissue. A sample of retroareolar tissue must be sent for intraoperative frozen section analysis. Different ways to obtain the nipple margin have been described ; the goal is to ensure complete excision of ductal tissue beneath the nipple ( Fig. 43.2 ).

In cases of risk-reduction NSMs where the risk of cancer is low, intraoperative evaluation of retroareolar tissue is not recommended.

The occurrence of a positive nipple margin ranges between 3% and 21%. If the final pathology shows disease in the nipple margin, then the current standard practice is complete excision of the skin of the NAC. Generally, pathologic examination of this NAC excision does not show additional tumor. Early results suggest that excision of the nipple with retention of the areola is a safe approach for management of a positive nipple margin after NSM.