Patient sample

A retrospective review of patients undergoing bilateral risk-reducing mastectomy between January 2010 and May 2022 from a single tertiary referral centre was performed. Specific approval from the IRB/Ethics Committee was not required for this retrospective project as all data had been collected already as part of routine clinical patient care, and therefore the work falls under the remit of Audit and Clinical Governance Service Improvement Projects. IRB approval is not required for such projects which do not alter the care of the patients in the study and registration numbers are not issued by the ethics committee for such projects that do not fall under their remit. Approval for undertaking this retrospective project was granted by the hospital’s audit and clinical governance department, and all ethical principles were followed in the creation of this manuscript. The hospital project ID is 3160 and hospital project registration number is PRN9160. Patients were identified from the prospectively maintained departmental breast reconstruction register together with operating theatre records. Data were then extracted from an archival electronic hospital records system for cases diagnosed prior to October 2014 and EPIC Systems Corporation for cases thereafter. All patients undergoing risk-reducing mastectomy were included, irrespective of any breast reconstruction. As this data were collected as part of routine clinical care provided to patients, consent did not need to be sought specifically for this retrospective paper. There were no patient identifying data. All patients were counselled and informed on the benefits versus risks of treatment options as part of ongoing routine care.

Data collection

Data collected included demographics, body mass index (BMI), pre-operative genetic test results, family history of breast or ovarian cancer, comorbidities, performance status (classified by the American Society of Anaesthesiologists [ASA] score), and smoking status at time of surgery. The following factors were also recorded: 1) type of mastectomy (simple, skin-sparing, nipple-sparing, or skin-reducing) 2) reconstruction technique (implant-based, solely autologous, or implant-assisted flaps) 3) laterality of RRM (unilateral or bilateral) 4) postoperative histopathology 5) 3-month post-operative complications (rates of flap/ implant loss, necrosis, infection and reoperation/ readmission) 6) any de novo cancer occurrence 7) whether risk-reducing salpingo-oophrectomy had been performed and 8) the timing of this in relation to the BRRM. Readmission was defined as any inpatient stay related to the surgical procedure after primary discharge. Reoperation was defined as any major surgical procedure requiring unplanned return to the operating room. Final follow-up was taken to be the most recent oncology, breast surgery or plastic surgery appointment with a clinician.

Statistical analyses

Statistical analysis was performed using IBM SPSS statistical software (v28.0; IBM Corp., Armonk, New York, USA). The cohort was divided into two groups with group 1 corresponding to patients undergoing surgery berween January 2010 and December 2014 and group 2 between January 2015 and April 2022. This turning point between the two groups was an arbitrary time point that allowed for coverage of similar periods of time in both groups, and therefore observation of trends over time, as well as coinciding with the adoption of our totally electronic patient record and a lowering of the national threshold for genetic testing from a likelihood of 20% to 10%. Pearson’s chi-squared test was used for comparison of categorical variables with post-hoc analysis performed for sub-group analysis. Fisher’s exact test was used where expected counts were below five. For comparing continuous data, analysis of normality using the Kolmogorov-Smirnov and Shapiro-Wilks tests alongside visual inspection of normal Q-Q plots was conducted, with the independent T-test used for normally distributed data and the Mann-Whitney U test for nonparametric data. A value of p<0.05 was considered to be significant.

Indications for BRRM

BRRM can reduce breast cancer risk by more than 90% in patients with BRCA gene mutations and/or family history and is the most effective prophylactic therapy against breast cancer development [16,17]. Inherited mutations in high penetrance breast cancer susceptibility genes such as BRCA1 and BRCA2 are associated with relatively high lifetime breast cancer risk [6]. In the present study, all but one patient underwent genetic testing, with more than three-quarters (86.59%) testing positive for a mutation. However, it should be noted that whilst genetic testing can exclude carriage of a known familial gene mutation, limitations of current technologies and intrinsic genetic test sensitivity (approximately 85%) prevent some mutations from being detected and any prophylactic intervention can only be based on family history of breast cancer [18,19]. The small number of patients in the present study without an identified mutation had a strong family history of breast cancer, and were therefore appropriate candidates for BRRM (Fig 1) [6].

Increased use of nipple-sparing mastectomy (NSM)

A nipple-sparing approach to mastectomy has historically been associated with concerns about risk of nipple-areolar-complex (NAC) necrosis and de novo cancer in residual tissue. However, growing evidence for its oncological safety combined with cosmetic appeal and positive psychological adjustment has led to increasing popularity of NSM as a prophylactic procedure [20,21]. The current study highlights a significant increase in rates of NSM from approximately one in seven (14.6%) for the early period to more than half (56.1%) of all BRRMs for the second time period. This is consistent with an upwards trend internationally [20]. Furthermore, there is no evidence from the current study for any increase in de novo breast cancer which therefore supports current literature on the safety of NSM for BRRM [22]. Although candidacy for NSM is usually predicated on a patient having relatively small breasts without ptosis, eligibility criteria in terms of breast size and degree of ptosis have expanded in recent years, with a variety of incisions developed to manage ptosis and enable skin reduction if necessary [23]. Of the 29 patients who underwent NSM across the entire study period, six developed necrosis involving one or both nipples that required surgical debridement (20.7%)–this is a similar figure to other published reports although lack of standard methods for assessment of necrosis has resulted in a wide range of reported rates [24–26]. Smoking is an established risk-factor for NAC necrosis due to adverse effects on macro and microvasculature [26]. Two-thirds (4/6) of patients with NAC necrosis in this study were ex-smokers; clinician-led encouragement and public health initiatives, may reduce the chance of necrotic complications if smoking is avoided or curtailed prior to surgery. Furthermore, the type and length of incision for NSM influence risk of necrosis and therefore both patient and surgical factors need to be carefully assessed when determining candidacy for NSM [26].

Reconstruction and ADM

This study reveals a significant decrease in flap-implant combined reconstruction and is consistent with nationwide trends documenting a sharp decline in combined procedures, particularly implant-assisted LD flaps [27,28]. This may partly be attributed to the advent of ADM and mesh devices. These act as biological scaffolds that become incorporated into host tissue and provide additional tissue coverage for implant-only reconstruction with more effective healing and reduction in rates of peri-implant inflammation and capsular contracture [29]. Indeed, this preference for implant reconstruction without autologous tissue has also has been encouraged by availability of a more comprehensive selection of implants that permit a more tailored surgical approach and “individualisation” of outcomes [30].

Increased use of the prepectoral approach in implant-based reconstruction

Although a subpectoral approach for implant placement has been conventional for breast reconstruction, ADMs have permitted the alternative option of prepectoral placement of implants that are encased by “mesh”. This approach reduces animation deformity and post-operative pain scores by leaving the pectoralis major muscle undisturbed, while simultaneously addressing problems of inadequate soft tissue support for implants placed subcutaneously. Current cosmetic outcomes and complication rates appear comparable to subpectoral placement although there is a lack of long-term efficacy data on the advantages of prepectoral reconstruction [31,32].

The current study found a significant increase in prepectoral breast reconstruction over time, although numbers remain low (only 6/26 for group 2). This is partly explained by stringent patient selection criteria with clear contraindications to pre-pectoral IBBR that include: poor skin quality/vascular compromise of skin flaps, poorly controlled diabetes, active tobacco use, previous or planned radiotherapy and presence of invasive tumour [33]. Younger patients are more likely to be physically active and are more often considered for a prepectoral approach [32]. There are a dearth of studies examining use of prepectoral implants for reconstruction after BRRM. Two studies have reported high levels of patient satisfaction and low complication rates [34,35]. This upwards trend in use of prepectoral reconstruction is likely to continue for two important reasons. Firstly, an increasing number of cases of risk-reducing mastectomy are being performed in younger patients, with greater absolute benefit for life-expectancy when RRM is performed at an early age [32]. Secondly, Marks et al conducted a survey revealing that almost 50% of American plastic surgeons used prepectoral techniques in “all” or “most” cases of breast reconstruction. Moreover, prepectoral IBBR was more likely to be adopted by surgeons with less than 15 years’ experience [36], suggesting that contemporaneously trained surgeons are more receptive to and proficient with this technique.

Limitations and COVID-19 considerations

There are some limitations to this study. Firstly, the follow-up range is wide, with three patients undergoing surgery in the final year of the study period. Sample size is relatively small and longer follow-up as well as larger sample sizes are required to more accurately determine rates of de novo breast cancer development and to characterise long-term complications such as development of capsular contracture more accurately.

Furthermore, several different breast surgeons have performed risk-reducing breast surgery over the decade in question and this may be reflected in mastectomy trends (especially for NSM). However, trends in reconstruction are less likely to be attributed to staff changes in this study as the same three plastic surgeons performed the majority of reconstructions up until 2015 after which one oncoplastic breast surgeon undertook both the extirpative and reconstructive components of surgery.

The COVID-19 pandemic limited the practice of BRRM and reconstruction due to restricted operative capacity, prioritisation of urgent cancer cases and cancellation of elective cases. As such, only five patients had surgery between January 2020 and the end of the study period (May 2022), with two cases of conventional mastectomy without reconstruction during this later time period. It would be useful to characterise the future trends in reconstructive practices post-pandemic with recent events having accelerated a decline in autologous tissue reconstruction [37].

Improvements in surgical techniques and materials technology should focus on maximising risk reduction while optimising functional, aesthetic and quality of life outcomes.

Conclusion

The current study highlights the changing landscape of bilateral risk-reducing mastectomy and reconstruction, reflecting a national shift towards more nipple-sparing approaches and fewer complex autologous procedures. When considering the range of techniques within both mastectomy and associated reconstruction, several permutations of surgical options can be offered to patients. As breast surgery continues to evolve, it is important to evaluate specific trends such as more conservative forms of mastectomy as well as novel techniques and devices for breast reconstruction to ensure optimal patient care and levels of satisfaction.