Symmetric Breast Surgery: Balancing Procedures versus Prophylactic Mastectomy and Immediate Reconstruction.

BACKGROUND: Various techniques for management of the contralateral breast exist in patients with unilateral breast cancer, including contralateral prophylactic mastectomy with immediate breast reconstruction (PMIBR), and symmetrization techniques including augmentation, reduction, or mastopexy. The purpose of this prospective cohort study was to evaluate and compare complications and patient-reported satisfaction of patients with contralateral PMIBR versus having symmetrization procedures. METHODS: A 7-year, single-institution, prospectively maintained database was reviewed. Patient-reported BREAST-Q scores were obtained at baseline, 3 months, and 12 months prospectively. Postoperative complications, oncologic outcomes, and BREAST-Q scores were compared. RESULTS: A total of 249 patients were included, 93 (37%) of whom underwent contralateral PMIBR and 156 (63%) of whom underwent contralateral symmetrization. The patients who underwent PMIBR were younger and had less comorbidities compared with patients with symmetrization. Rates of major and minor complications were similar, apart from higher rates of minor wound dehiscence in the PMIBR group. When comparing mean change at 12-month follow-up to preoperative results, there was a significant decrease in physical well-being of the chest in the symmetrization compared with the PMIBR group (2.94 versus -5.69; P = 0.042). There were no significant differences in mean breast satisfaction and psychosocial well-being, and nonsignificant decreases in sexual well-being between groups. CONCLUSIONS: Patients with unilateral breast cancer who underwent immediate contralateral breast management, with either contralateral PMIBR or symmetrization techniques, demonstrated similar profiles of major complications and good overall satisfaction except for one physical well-being domain. Management of the contralateral breast with symmetrization may provide similar outcomes compared with PMIBR, which often is considered not necessary in patients without specific indications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Contralateral prophylactic mastectomy: Weighing the risks of delayed chemotherapy, radiotherapy, and hormonal therapy.

BACKGROUND: Many patients with unilateral breast cancer opt for contralateral prophylactic mastectomy (CPM) at the time of therapeutic mastectomy (immediate CPM) or following completion of adjuvant therapy. Studies show that immediate CPM increases the risk of surgical complications related to unilateral mastectomy (UM) alone, which may lead to delays in adjuvant therapy initiation. However, it is unclear if these complications cause clinically significant delays in initiating adjuvant chemotherapy, radiotherapy, or hormonal therapy. METHODS: A retrospective chart review was conducted on patients with breast cancer who underwent immediate CPM versus UM alone at Columbia University Medical Center from January 2000 to December 2020. Patient demographic and oncologic characteristics; complications; and timing of adjuvant chemotherapy, radiotherapy, and/or hormonal therapy relative to therapeutic mastectomy were collected. RESULTS: In this study, 239 UM alone patients were propensity score matched to 239 immediate CPM patients. No significant difference in complication rates was found between the index and contralateral breasts in CPM patients. A similar percentage of CPM and UM patients experienced postoperative complications (19% vs. 17%, p = 0.64). No significant difference in time to adjuvant chemotherapy, radiotherapy, or hormonal therapy was found between CPM patients with complications and all CPM patients or all UM patients. CONCLUSIONS: There is a lack of clear guidance for clinical decision-making regarding timing of CPM relative to adjuvant therapy. Our study suggests that immediate CPM does not significantly increase the risks of postoperative complications or complication-related delays in the initiation of adjuvant chemotherapy, radiotherapy, or hormonal therapy. This information may help patients and providers to plan, select, and schedule breast cancer treatment options.

Preserving choice in breast cancer treatment: A different perspective on contralateral prophylactic mastectomy.

Contralateral prophylactic mastectomy is the removal of both breasts when only one is affected by cancer. Rates of this controversial cancer treatment have been increasing since the late 1990s, even among women who do not have the kind of family history or known genetic mutation that would put them at high-risk for another breast cancer. Citing contralateral prophylactic mastectomy's lack of oncologic benefit and increased risk of surgical complications, the American Society of Breast Surgeons discourages contralateral prophylactic mastectomy for average-risk women with unilateral cancer, as does most of the medical literature on this topic. Within this literature, desire for contralateral prophylactic mastectomy is often painted as the product of an emotional overreaction to a cancer diagnosis and misunderstanding of breast cancer risk. Drawing on the personal experience of a breast cancer survivor, as well as relevant medical literature on breast cancer screening and surgery, this article offers a different perspective on the ongoing popularity of contralateral prophylactic mastectomy, one that focuses on practical experiences and logical deliberations about those experiences. Specifically, it calls attention to two features of the contralateral prophylactic mastectomy decision-making situation that have been inadequately covered in the medical literature: (1) the way that breast cancer screening after a breast cancer diagnosis can become a kind of radiological overtreatment, even for "average-risk" women; and (2) how desire for bodily symmetry after breast cancer, which can best be achieved through bilateral reconstruction or no reconstruction, drives interest in contralateral prophylactic mastectomy. The goal of this article is not to suggest that all women who want contralateral prophylactic mastectomy should have the surgery. In some cases, it is not advisable. But many "average-risk" women with unilateral cancer have good reasons for wanting contralateral prophylactic mastectomy, and we believe their right to choose it should be protected.

Complications Associated with Contralateral Prophylactic Mastectomy: A Systematic Review and Meta-Analysis.

BACKGROUND: No meta-analysis has examined whether contralateral prophylactic mastectomy increases complication risk for unilateral breast cancer patients undergoing unilateral mastectomy. METHODS: Fifteen studies on complications of unilateral mastectomy plus contralateral prophylactic mastectomy met inclusion criteria. Meta-analyses compared complications of (1) diseased versus contralateral breasts in unilateral plus contralateral prophylactic mastectomy patients and (2) patients undergoing unilateral plus contralateral prophylactic mastectomy versus unilateral alone when grouped by reconstructive method. RESULTS: For all unilateral plus contralateral prophylactic mastectomy patients, the diseased breast was significantly more prone to complications versus the contralateral breast (relative risk, 1.24; p = 0.03). In studies that stratified by reconstructive method, the complication risk was significantly higher for unilateral plus contralateral prophylactic mastectomy versus unilateral mastectomy alone for patients with no reconstruction (relative risk, 2.03; p = 0.0003), prosthetic-based reconstruction (relative risk,1.42; p = 0.003), and autologous reconstruction (relative risk, 1.32; p = 0.005). The only prospective trial showed similar results, including for more severe complications. Smaller retrospective studies without stratification by reconstructive method showed similar complications for unilateral plus contralateral prophylactic mastectomy versus unilateral mastectomy alone (relative risk, 1.06; p = 0.70). These groups had similar incidences of complication-related delay in adjuvant therapy, as demonstrated by one study. CONCLUSIONS: After unilateral plus contralateral prophylactic mastectomy, diseased breasts are at higher risk for complications. Stronger evidence supports higher complication risk for unilateral plus contralateral prophylactic mastectomy than unilateral alone. More work is needed to determine the effect of complications on timing of adjuvant therapy.

A Comparison of Complications in Therapeutic versus Contralateral Prophylactic Mastectomy Reconstruction: A Paired Analysis.

BACKGROUND: Although breast reconstruction after bilateral mastectomies including a contralateral prophylactic mastectomy is known to have a higher overall complication profile, whether reconstructive complication rates differ between the therapeutic mastectomy and contralateral prophylactic mastectomy sides remains unclear. METHODS: Women undergoing bilateral mastectomies with autologous or implant-based breast reconstruction for a unilateral breast cancer at a single institution were identified (2009 to 2019). Postoperative complications were stratified by laterality (therapeutic mastectomy versus contralateral prophylactic mastectomy). Paired data were analyzed to compare the risks of complications between prophylactic and therapeutic reconstruction sides in the same patient. RESULTS: A total of 130 patients (260 reconstructions) underwent bilateral autologous or implant-based reconstruction. Although most women underwent a simple mastectomy, a higher proportion of therapeutic mastectomies were modified radical mastectomies including axillary lymph node dissections compared to contralateral prophylactic mastectomies (15.4 percent versus 0 percent). Forty-four percent of women completed postmastectomy radiation therapy of the therapeutic side before definitive reconstruction. Overall, both therapeutic and prophylactic reconstructions had a similar incidence of reconstructive failure (p = 0.57), return to the operating room (p = 0.44), mastectomy skin flap necrosis (p = 0.32), seroma (p = 0.82), fat necrosis (p = 0.16), wound infection (p = 0.56), and cellulitis (p = 0.56). Nearly one-fifth of patients experienced complications limited to the prophylactic side [contralateral prophylactic mastectomy reconstruction complications, n = 26 (20.0 percent); therapeutic mastectomy reconstruction complications, n = 15 (11.5 percent)]. CONCLUSION: Despite a history of local radiation therapy and more extensive oncologic surgery on the therapeutic side, there are no significant differences in the incidence of postsurgical complications on the therapeutic mastectomy and contralateral prophylactic mastectomy sides after bilateral reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

[Prophylactic mastectomy and occult cancer: a ten-year experience at a cancer center]. / Chirurgie de réduction de risque mammaire et découverte fortuite de cancer : dix ans d'expérience dans un centre de lutte contre le cancer.

INTRODUCTION: Women identified as high-risk for breast cancer may choose between close follow-up and radical mastectomy. Prophylactic mastectomy, as any other surgery, is associated with benefits and harms. The aim of this study was to assess the morbidity associated with prophylactic mastectomy and to evaluate the prevalence of occult cancers. METHODS: All patients who underwent unilateral or bilateral prophylactic mastectomy between 2007 and 2017 in our institution were eligible for inclusion in this retrospective study. Medical history, type of surgery, occurrence of complication or reoperation and pathological reports were examined in medical charts. RESULTS: 79 women underwent prophylactic mastectomy over the studied period of which 58.2% were contralateral after breast cancer. A genetic mutation was present in 86.1% of cases. Postoperative complications occurred in 43.0% of cases. An additional surgery for medical or esthetic purpose was needed in 72.1% of cases. Occult cancer was found in 11.4% of the pathological reports. Triple negative invasive ductal carcinoma was discovered in two cases (2.5%). DISCUSSION: Prophylactic mastectomy is the only effective preventive action against breast cancer. Women must be clearly informed of possible complications, high reoperation rate and potential pathological findings. Identifying women most at risk for breast cancer would help to better target those who will benefit most from surgery.

Understanding Stakeholder Preference for Contralateral Prophylactic Mastectomy: A Conjoint Analysis.

BACKGROUND: Despite increasing numbers of women with unilateral breast cancer undergoing CPM, quantitative evidence of all stakeholder preferences regarding CPM is lacking, particularly for healthy volunteers. Conjoint analysis, a marketing tool, can be used to quantify tradeoffs surrounding CPM. STUDY DESIGN: The objective of this study was to quantify preferences for aspects of contralateral prophylactic mastectomy (CPM) decision-making process among key stakeholders. Healthy volunteers, women with cancer (WwCa), surgical oncologists, and plastic surgeons were surveyed with the same conjoint simulation exercise. Respondents chose between either single (SM) or double (DM) mastectomy under varying recurrence and complication rates, surveillance, and symmetry conditions. Hierarchical Bayesian models calculated partworth utilities and importance scores. RESULTS: Overall, 1,244 respondents participated. The top 3 important factors for all stakeholders were surgical complication rates after DM, type of surgery (SM vs DM) independent of other variables, and 10-year future contralateral cancer risk after SM. HV and surgeons placed greatest importance on high rates of surgical complications after DM. WwCa preferred DM, regardless of complication risk or low rates of a 10-year future cancer episode after SM. Surgical oncologists strongly preferred SM and were more accepting of future cancer risk of 3% or 10% than other stakeholders. Symmetry and need for surveillance were least important factors for all stakeholders. CONCLUSIONS: The threshold of acceptability for future cancer episodes and risk tolerance for complications varies by stakeholder, with a profound influence upon WwCA. Current findings suggest room for improved provider and patient alignment through behavioral techniques, such as framing, meanwhile highlighting changes in risk perception after a breast cancer diagnosis.

Secondary Angiosarcoma With C-MYC Amplification Following Prophylactic Bilateral Mastectomy and Autologous Breast Reconstruction: Report of a Case and Review of the Literature.

In this article, we report a very rare case of secondary angiosarcoma in a young woman with no prior history of breast cancer who had bilateral prophylactic mastectomies with autologous reconstruction due to a strong family history of breast cancer and BRCA1 gene variant of uncertain significance. The surgery was complicated by recurrent fat necrosis requiring several excisions and additional reconstruction followed by the development of localized lymphedema and subsequent angiosarcoma in the reconstructed breast 10 years later. The angiosarcoma was high grade with prominent epithelioid features associated with abundant tumor-infiltrating lymphocytes. Amplification of C-MYC locus 8q21.24 was demonstrated by fluorescence in situ hybridization study. We postulate that chronic trauma from several surgeries including tissue hypoxia and impaired lymphatic drainage may have provided a milieu for angiogenesis and mutagenic transformation. Amplification of C-MYC locus 8q21.24 was most likely a strong oncogenic driver of angiosarcoma. To the best of our knowledge, this is the first report of its kind in the literature.

Bilateral immediate two-stage breast reconstruction in patients with unilateral breast cancer: Outcomes analysis and risk assessment.

INTRODUCTION: Contralateral prophylactic mastectomy has the potential to decrease the occurrence of cancer and reduce psychological burden. However, it is known that complications after bilateral mastectomy are higher compared with unilateral mastectomy. Our goal was to evaluate outcomes of immediate breast reconstruction in patients undergoing bilateral mastectomy and to compare complication rates between therapeutic and prophylactic sides. PATIENTS AND METHODS: Electronic medical records of patients with unilateral breast cancer who underwent bilateral mastectomy and immediate reconstruction with expanders were reviewed. Postoperative complications were compared between therapeutic and prophylactic mastectomy sides. RESULTS: Sixty-two patients were analyzed. The overall complication rate after both stages was 23.9% on the therapeutic side and 16.5% on the prophylactic side. Infection was the most common complication on both sides. All infections on the prophylactic mastectomy side were successfully treated with intravenous (IV) antibiotics (salvage rate of 100%), whereas 35.7% of infected tissue expander/implants on the therapeutic mastectomy side were explanted despite treatment. CONCLUSION: Careful counselling of patients undergoing elective contralateral prophylactic mastectomy is essential as complications can develop in either breast after reconstruction.

Complications of Contralateral Prophylactic Mastectomy: Do They Delay Adjuvant Therapy?

BACKGROUND: There is ongoing debate regarding the optimal timing of contralateral prophylactic mastectomy fueled by concern that performing it at the time of the mastectomy for the index breast cancer may delay adjuvant therapy. The study objective was to examine the effect of simultaneous contralateral prophylactic mastectomy with immediate breast reconstruction on the complication rate and adjuvant therapy timing. METHODS: A retrospective study was conducted of consecutive patients who underwent contralateral prophylactic mastectomy with immediate breast reconstruction and received adjuvant therapy over a 6-year period. Demographic, treatment, and outcomes data were collected, and relationships between multiple variables and outcomes were evaluated. RESULTS: Of 241 patients (482 breasts) included, 186 (372 breasts) underwent simultaneous index breast mastectomy and contralateral prophylactic mastectomy with immediate breast reconstruction followed by adjuvant therapy (immediate group), and 55 (110 breasts) underwent index mastectomy, then adjuvant therapy, followed by delayed contralateral prophylactic mastectomy with immediate breast reconstruction (delayed group). Demographics were similar, although breast cancer stage (p < 0.001), tumor category (p = 0.0072), and nodal category (p < 0.001) were significantly higher in the delayed group. In the immediate group, complications before adjuvant therapy occurred in 31 patients (16.7 percent), and in six patients (3.2 percent) complications occurred only in the contralateral prophylactic mastectomy breast; delay to adjuvant therapy occurred in 11 patients (5.9 percent), in four (2.2 percent) of whom the contralateral prophylactic mastectomy breast was responsible for the delay. CONCLUSIONS: Contralateral prophylactic mastectomy with immediate breast reconstruction can be performed safely at the time of the index mastectomy in carefully selected patients. These findings will engage patients seeking contralateral prophylactic mastectomy in shared decision-making regarding optimal timing with respect to the risks and benefits. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Second primary breast cancer after unilateral mastectomy alone or with contralateral prophylactic mastectomy.

BACKGROUND: An increasing number of patients undergo contralateral prophylactic mastectomy (CPM) for unilateral breast cancer. However, the benefit of CPM has not been quantified in the setting of contemporary breast cancer therapy. METHODS: We performed an analysis of 180 068 patients in the Surveillance, Epidemiology, and End Results (SEER) database, diagnosed with unilateral ductal breast carcinoma between 1998 and 2013 and treated with unilateral mastectomy (UM) or CPM. UM was performed in 146 213 patients (81.2%); CPM was performed in 33 855 patients (19.8%). Primary outcome of interest was cumulative incidence of a second primary breast cancer in the ipsilateral or contralateral breast greater than 3 months after initial diagnosis. Cumulative incidence analysis was based on a Cox proportional model to generate curves of second primary breast cancer in any breast, ipsilateral breast only, or contralateral breast only. RESULTS: Patients who underwent CPM had a significantly reduced incidence of second primary breast cancer 10 and 15 years after surgery (CPM 0.93% [0.73%, 1.12%] vs UM 4.44% [4.28%, 4.60%]). Patients who underwent CPM had significantly lower adjusted hazard of second primary breast cancer when compared with UM (HR 0.38 vs 1.0, P < .0001). CONCLUSIONS: CPM offers some protection from a second primary breast cancer, attributable to a reduced incidence in the contralateral breast. These findings provide additional information to providers and patients as they make decisions regarding surgical management. They should also be interpreted in the context of the absolute incidence of second primary breast cancer after UM and previous literature demonstrating no survival benefit.

The relationship between contralateral prophylactic mastectomy and breast reconstruction, complications, breast-related procedures, and costs: A population-based study of health insurance data.

BACKGROUND: Increasingly, women are undergoing contralateral prophylactic mastectomy for the treatment of unilateral breast cancer. The relationship between contralateral prophylactic mastectomy and breast reconstruction, postsurgical complications, additional breast-related procedures, and cost has not received the attention it deserves. METHODS: Data from the New York comprehensive, all-age, all-payer, Statewide Planning and Research Cooperative System were queried to identify patients undergoing unilateral mastectomy or contralateral prophylactic mastectomy from 2008 to 2010. We identified the complications and breast-related procedures within a 2-y follow-up period. Costs of the index operation and subsequent follow-up were estimated. Univariate and multivariate analyses were conducted. RESULTS: Of 12,959 women identified, 10.7% underwent contralateral prophylactic mastectomy. On univariate analysis, contralateral prophylactic mastectomy was positively associated with breast reconstruction, complications, and additional breast-related procedures. Rates of complications were greater for women who had contralateral prophylactic mastectomy (29.5% vs 20.8% for unilateral mastectomy group; P < .001), but not after stratifying by breast reconstruction. Additional breast-related procedures were more common in the contralateral prophylactic mastectomy group than in the unilateral mastectomy group, but only for those who underwent breast reconstruction (82.8% vs 72.1%; P < .001). Unadjusted costs were greater for women with contralateral prophylactic mastectomy than with unilateral mastectomy but did not differ between the groups after adjusting for breast reconstruction and additional breast-related procedures. CONCLUSION: Women who elected contralateral prophylactic mastectomy in this population-based study were more likely to have both breast reconstruction and additional breast-related procedures than women with unilateral mastectomy. The greater rates of complications and costs associated with contralateral prophylactic mastectomy were explained by breast reconstruction and additional breast-related procedures. Surgeons should counsel patients regarding the increased cost and likelihood of undergoing additional, non-complication-related procedures after contralateral prophylactic mastectomy with breast reconstruction.

Risk-reducing mastectomy: a case series of 124 procedures in Brazilian patients.

PURPOSE: Women with mutations in breast cancer predisposition genes have a significantly higher lifetime risk of developing breast cancer and can opt for risk-reducing mastectomy. Women with positive family history of cancer can also opt for prophylactic surgery as a preventive method in selected cases. Current studies showed reduced risk of developing breast cancer after prophylactic nipple-sparing mastectomy, however, despite the good clinical outcomes, one of the main concerns regarding nipple-sparing mastectomy (NSM) is the oncological safety of nipple-areola complex preservation. In this study, we aimed to evaluate the indications, complication rates, and unfavorable events of 62 Brazilian patients that underwent risk-reducing NSM from 2004 to 2018. METHODS: Patient data were reviewed retrospectively and descriptive statistics were utilized to summarize the findings. RESULTS: The mean patients age was 43.8 years. The main indication for risk-reducing NSM was the presence of pathogenic mutation (53.3%), followed by atypia or lobular carcinoma in situ (25.8), and family history of breast cancer and/or ovarian cancer (20.9%). There were four (3.2%) incidental diagnosis of ductal carcinoma in situ and one invasive ductal carcinoma (0.8%). From the 124 prophylactic NSM performed, two (1.6%) complications had occurred: one (0.8%) infection and one (0.8%) partial nipple necrosis. In a mean follow-up of 50 months, there was one (1.6%) newly diagnosed breast cancer in the 62 patients undergoing prophylactic NSM. CONCLUSIONS: Our findings demonstrated efficacy and safety to perform NSM as prophylactic surgery with good oncological outcomes and low complication rates in a case series of Brazilian patients.

Assessing the additional surgical risk of contralateral prophylactic mastectomy and immediate breast implant reconstruction.

INTRODUCTION: There has been a sharp rise in the rate of contralateral prophylactic mastectomy over the last decade, despite the low incidence of new primary cancers predicted for the contralateral breast. This study compares the postoperative complication rates between the diseased breast treated with mastectomy and the contralateral breast that underwent prophylactic mastectomy, followed by immediate bilateral breast implant reconstruction. We hypothesized that there will be no difference in postoperative outcomes between prophylactic and diseased groups, as the surgical approach would be comparable. METHODS: After IRB approval, a retrospective chart review identified consecutive unilateral breast cancer patients who underwent bilateral mastectomy and immediate breast reconstruction between May 2008 and May 2018 at a tertiary academic medical center. A paired sample t-test and a penalized logic regression model were constructed to identify relationships between breast laterality and outcomes. RESULTS: A total of 1117 patients with unilateral breast cancer who underwent bilateral mastectomy and immediate breast implant reconstruction were identified. Rates of capsular contracture and infection were significantly greater in the diseased breast, while rates of revision were significantly greater in the contralateral prophylactic breast. There were no statistically significant differences between breasts in rates of explant, skin flap necrosis or hematoma. When adjusted for confounding variables, a higher infection rate was observed in the diseased breast. CONCLUSION: This study detected significant differences in postoperative complication rates between the diseased and prophylactic breasts following bilateral mastectomy and immediate breast implant reconstruction. Postoperative complications occurred more frequently in the diseased breast compared with low rates of complications in the contralateral prophylactic breast. This information is helpful for preoperative decision making, as surgeons and patients carefully weigh the additional risks of contralateral prophylactic procedure.

Postoperative complications in combined gynecologic, plastic, and breast surgery: An analysis from National Surgical Quality Improvement Program.

Patients undergoing the addition of a contralateral prophylactic mastectomy with unilateral breast cancer have an increased and potentially doubled post-operative complication rate. One documented detriment from post-operative complications is the potential delay in initiating adjuvant therapy. To determine if the addition of a gynecologic and/or plastic reconstructive procedure to breast surgery results in an increased risk of postoperative complications and re-admissions, we evaluated outcomes in patients undergoing single vs multi-site surgery in a large national surgical database. We utilized the National Surgery Quality Improvement Program (NSQIP) database to identify patients who underwent breast surgery between 2011 and 2015. We extracted patients who underwent prophylactic oophorectomy with or without hysterectomy as a comparison group. Chi square analysis was used to assess postoperative outcomes including complications, readmission, and reoperation. All statistics were performed in SPSS v. 24. During the study timeframe, 77 030 patients had a solitary or combined breast surgical procedure and a second cohort of 124 patients underwent gynecologic surgery. Breast cancer patients who did not have a simultaneous reconstruction or gynecologic procedure were older with more comorbidities. Patients undergoing coordinated procedures had a significantly longer length of stay, higher complication, readmission, and reoperation rates (P < 0.001 for all) as compared with patients who underwent single site surgery. Patients with surgery for breast cancer, either with a plastic or gynecologic procedure, have greater postoperative complications. Higher complication rates for those with coordinated operations may lead to delays in adjuvant therapy and discussions regarding the indications for simultaneous surgery are recommended.

Residual glandular tissue (RGT) in BRCA1/2 germline mutation carriers with unilateral and bilateral prophylactic mastectomies.

BACKGROUND: Prophylactic mastectomy (PME) is increasingly performed in women carrying deleterious BRCA1 and BRCA2 germline mutations. The oncologic risk resulting from residual fibroglandular tissue (RGT) is unknown. METHODS: All women who had received a mastectomy and at least one postoperative breast MRI, between 2006 and 2016 were extracted from the register of the Center for Hereditary Breast and Ovarian Cancer Cologne (CHBOC). The index MRI was evaluated in terms of basic clinical data and the morphological criteria of RGT. The RGT volume was measured in diameter and was semi-automatically evaluated using software. RESULTS: We identified 169 women carrying BRCA1/2 mutations who underwent prophylactic and curative mastectomy: a total of 338 breasts. RGT was found in 128 of the 338 breasts (37.9%). 68 of the 128 breasts (53.1%) were related to bilateral PME, 37 (28.9%) to unilateral PME and 23 (18.0%) to curative mastectomy. RGT was predominantly unifocal and located in the retroareolar breast region. RGT was observed more often after bilateral PME (p < 0.0001). In this subgroup, the nipple-sparing mastectomy dominated (108 of 136, 79.4%), in contrast to 23 standard mastectomies (23 of 94, 24.5%) in the subgroup of curative mastectomy (23%). There was a trend towards higher amounts of RGT in surgical units with fewer mastectomies performed. During follow-up, two breast cancers were detected after bilateral and unilateral PME, respectively. CONCLUSIONS: Our results suggest that the indication for surgery and in particular the selected surgical procedure affect the surgical outcome with respect to RGT. Oncological safety should not be neglected, especially in the high-risk group of BRCA1/2 mutation carriers.