Decision analysis to assess the efficacy of routine sentinel lymphadenectomy in patients undergoing prophylactic mastectomy

Society of Surgical Oncology Breast Disease Site Working Group Statement on Contralateral Mastectomy: Indications, Outcomes, and Risks

Rates of contralateral mastectomy (CM) among patients with unilateral breast cancer have been increasing in the United States. In this Society of Surgical Oncology position statement, we review the literature addressing the indications, risks, and benefits of CM since the society's 2017 statement. We held a virtual meeting to outline key topics and then conducted a literature search using PubMed to identify relevant articles. We reviewed the articles and made recommendations based on group consensus. Patients consider CM for many reasons, including concerns regarding the risk of contralateral breast cancer (CBC), desire for improved cosmesis and symmetry, and preferences to avoid ongoing screening, whereas surgeons primarily consider CBC risk when making a recommendation for CM. For patients with a high risk of CBC, CM reduces the risk of new breast cancer, however it is not known to convey an overall survival benefit. Studies evaluating patient satisfaction with CM and reconstruction have yielded mixed results. Imaging with mammography within 12 months before CM is recommended, but routine preoperative breast magnetic resonance imaging is not; there is also no evidence to support routine postmastectomy imaging surveillance. Because the likelihood of identifying an occult malignancy during CM is low, routine sentinel lymph node surgery is not recommended. Data on the rates of postoperative complications are conflicting, and such complications may not be directly related to CM. Adjuvant therapy delays due to complications have not been reported. Surgeons can reduce CM rates by encouraging shared decision making and informed discussions incorporating patient preferences.

De-escalating axillary surgery in early-stage breast cancer

The role of axillary surgery has evolved over the last three decades from routine axillary lymph node dissection (ALND) to sentinel lymph node biopsy to omission of axillary surgery altogether in select patients. This evolution has been achieved through the design and conduct of multiple clinical trials demonstrating that ALND does not impact survival and is not necessary for local control in patients with early-stage breast cancer and limited nodal involvement. Importantly, this practice-changing shift mirrored the trend towards earlier stage at diagnosis and the recognition of the interplay between local and systemic therapies in maintaining local control. There are numerous clinical scenarios today in which axillary staging can be safely avoided, including (1) DCIS treated with lumpectomy, (2) at the time of contralateral prophylactic mastectomy, and (3) in elderly patients with early-stage, HR+/HER2-clinically node-negative (cN0) disease. Ongoing clinical trials seek to expand the cohorts in which surgical nodal staging can be omitted. These populations include a broader range of early-stage, cN0 patients undergoing upfront surgery, as seen in the SOUND, INSEMA, BOOG 2013-08, SOAPET and NAUTILUS trials. Omission of axillary surgery in cN0 patients with HER2+ or triple-negative disease treated with neoadjuvant chemotherapy is also being tested in the ASICS and EUBREAST-01 trials. Continued advances in imaging and the growing role of genomic assays in selecting patients for systemic therapy are likely to further minimize the need for axillary surgery; thereby further reducing the morbidity of local therapy for women with breast cancer.

The Use of Sentinel Lymph Node Biopsy in BRCA1/2 Mutation Carriers Undergoing Prophylactic Mastectomy: A Retrospective Consecutive Case-Series Study

INTRODUCTION

Sentinel lymph node biopsy in prophylactic mastectomy is controversial. It avoids lymphadenectomy in occult carcinoma but is associated with increased morbidity. Women with BRCA mutations have a higher incidence of occult carcinoma and our objective was to assess the clinical utility of sentinel lymph node biopsy when these women undergo prophylactic mastectomy.

MATERIALS AND METHODS

Seven-year retrospective consecutive case-series study of women, with a BRCA deleterious mutation, admitted to prophylactic mastectomy, at our center. Breast MRI < 6 months before surgery was routine, unless contraindicated.

RESULTS

Fifty-seven patients (43% BRCA1; 57% BRCA2) underwent 80 prophylactic mastectomies. 72% of patients had had breast cancer treated before prophylactic mastectomy or synchronously to it. The occult carcinoma incidence was 5%, and half of the cases were invasive. SLNB was performed in 19% of the prophylactic mastectomies; none of these had tumor invasion. Women with invasive carcinoma who had not undergone sentinel lymph node biopsy were followed closely with axillary ultrasound. The median follow-up was 37 months, with no local recurrence; 1 patient died of primary tumor systemic relapse.

CONCLUSIONS

Our data do not support this procedure for routine (in agreement with previous literature), in this high risk for occult carcinoma population.

Sentinel Lymph Node Biopsy in Breast Cancer: A Clinical Review and Update

Sentinel lymph node biopsy has become a standard staging tool in the surgical management of breast cancer. The positive impact of sentinel lymph node biopsy on postoperative negative outcomes in breast cancer patients, without compromising the oncological outcomes, is its major advantage. It has evolved over the last few decades and has proven its utility beyond early breast cancer. Its applicability and efficacy in patients with clinically positive axilla who have had a complete clinical response after neoadjuvant chemotherapy is being aggressively evaluated at present. This article discusses how sentinel lymph node biopsy has evolved and is becoming a useful tool in new clinical scenarios of breast cancer management.

Selective Use of Sentinel Lymph Node Surgery in Patients Undergoing Prophylactic Mastectomy Using Intraoperative Pathology

BACKGROUND

Routine sentinel lymph node (SLN) surgery during prophylactic mastectomy (PM) is unnecessary, because most PMs do not contain cancer. Our institution utilizes intraoperative pathology to guide the surgical decision for resection of SLNs in PM. The purpose of this study was to review the effectiveness of this approach.

METHODS

We identified all women aged ≥18 years who underwent bilateral PM (BPM) or contralateral PM (CPM) at our institution from January 2008 to July 2016. We evaluated the frequency of SLN resection and rate of occult breast cancer (DCIS or invasive disease) in the PM. We used the following definitions: over-treatment-SLN surgery in patients without cancer; under-treatment-no SLN surgery in patients with cancer; appropriate treatment-no SLN in patients without cancer or SLN surgery in patients with cancer.

RESULTS

PM was performed on 1900 breasts: 1410 (74.2%) CPMs and 490 (25.8%) BPMs. Cancer was identified in 58 (3.0%) cases (32 invasive disease and 26 DCIS) and concurrent SLN surgery was performed in 44 (75.9%) of those cases. Overall, SLN surgery guided by intraoperative pathology resulted in appropriate treatment of 1787 (94.1%) cases: 1319 (93.5%) CPMs and 468 (95.5%) BPMs, by avoiding SLN in 1743/1842 cases without cancer (94.6%), and performing SLN surgery in 44/58 cases with cancer (75.9%).

CONCLUSIONS

Use of intraoperative pathology to direct SLN surgery in patients undergoing PM minimizes over-treatment from routine SLN in PM and minimizes under-treatment from avoiding SLN in PM, demonstrating the value of intraoperative pathology in this era of focus on appropriateness of care.

Society of Surgical Oncology Breast Disease Working Group Statement on Prophylactic (Risk-Reducing) Mastectomy

Over the past several years, there has been an increasing rate of bilateral prophylactic mastectomy (BPM) and contralateral prophylactic mastectomy (CPM) surgeries. Since publication of the 2007 SSO position statement on the use of risk-reducing mastectomy, there have been significant advances in the understanding of breast cancer biology and treatment. The purpose of this manuscript is to review the current literature as a resource to facilitate a shared and informed decision-making process regarding the use of risk-reducing mastectomy.

The value of breast MRI in high-risk patients with newly diagnosed breast cancer to exclude invasive disease in the contralateral prophylactic mastectomy: Is there a role to choose wisely patients for sentinel node biopsy?

The aim of this study was to evaluate the presence of clinically and mammographically occult disease using breast MRI in a cohort of cancer patients undergoing contralateral prophylactic mastectomy (CPM) and the utmost indication of axillary assessment (sentinel node biopsy (SLNB)) for this side. A retrospective review of patients with unilateral invasive breast cancer or ductal carcinoma in situ (DCIS) from institutional MRI registry data (2004–2010) was conducted. Characteristics of patients undergoing CPM with breast MRI obtained less than 6 month before surgery were evaluated. A total of 2322 consecutive patients diagnosed with DCIS or stage I to III infiltrating breast cancer underwent preoperative breast MRI. Of these, 1376 patients (59.2%) had contralateral clinical breast exam and mammography without abnormalities; and 116 patients (4.9%) underwent CPM (28 excluded patients had breast MRI more than 6 months before CPM). The mean age of the 88 patients was 49 years (range 28–76 years). Two (2.3%) DCIS identified on surgical pathology specimen were not depicted by MRI and the 5 mm T1N0 invasive cancer (1.1%) was identified on MRI. Preoperative MRI showed 95% accuracy to demonstrate absence of occult disease with negative predicted value (NPV) of 98% (95% CI: 91.64–99.64%). Occult disease was present in 3.4% of CPM. MRI accurately identified the case of invasive cancer in this cohort. The high negative predictive value suggests that MRI can be used to select patients without consideration of SLNB for the contralateral side.

Concordance between decision analysis and matching systematic review of randomized controlled trials in assessment of treatment comparisons: a systematic review

Background

Systematic review (SR) of randomized controlled trials (RCT) is the gold standard for informing treatment choice. Decision analyses (DA) also play an important role in informing health care decisions. It is unknown how often the results of DA and matching SR of RCTs are in concordance. We assessed whether the results of DA are in concordance with SR of RCTs matched on patient population, intervention, control, and outcomes.

Methods

We searched PubMed up to 2008 for DAs comparing at least two interventions followed by matching SRs of RCTs. Data were extracted on patient population, intervention, control, and outcomes from DAs and matching SRs of RCTs. Data extraction from DAs was done by one reviewer and from SR of RCTs by two independent reviewers.

Results

We identified 28 DAs representing 37 comparisons for which we found matching SR of RCTs. Results of the DAs and SRs of RCTs were in concordance in 73% (27/37) of cases. The sensitivity analyses conducted in either DA or SR of RCTs did not impact the concordance. Use of single (4/37) versus multiple data source (33/37) in design of DA model was statistically significantly associated with concordance between DA and SR of RCTs.

Conclusions

Our findings illustrate the high concordance of current DA models compared with SR of RCTs. It is shown previously that there is 50% concordance between DA and matching single RCT. Our study showing the concordance of 73% between DA and matching SR of RCTs underlines the importance of totality of evidence (i.e. SR of RCTs) in the design of DA models and in general medical decision-making.

Prophylactic Mastectomy: An Appraisal

The main indication of prophylactic mastectomy pertains to BRCA1 or BRCA2 mutation carriers. Prophylactic mastectomy includes the simple method and the subcutaneous method. Both methods can be followed by breast plastic reconstruction either at the same time or later. This review examines key issues regarding prophylactic mastectomy: the selection of patients, its effectiveness, its limitations, convergence/divergence in existing guidelines, and future perspectives.

Sentinel lymph node biopsy at the time of mastectomy does not increase the risk of lymphedema: implications for prophylactic surgery

Women diagnosed with or at high risk for breast cancer increasingly choose prophylactic mastectomy. It is unknown if adding sentinel lymph node biopsy (SLNB) to prophylactic mastectomy increases the risk of lymphedema. We sought to determine the risk of lymphedema after mastectomy with and without nodal evaluation. 117 patients who underwent bilateral mastectomy were prospectively screened for lymphedema. Perometer arm measurements were used to calculate weight-adjusted arm volume change at each follow-up. Of 234 mastectomies performed, 15.8 % (37/234) had no axillary surgery, 63.7 % (149/234) had SLNB, and 20.5 % (48/234) had axillary lymph node dissection (ALND). 88.0 % (103/117) of patients completed the LEFT-BC questionnaire evaluating symptoms associated with lymphedema. Multivariate analysis was used to assess clinical characteristics associated with increased weight-adjusted arm volume and patient-reported lymphedema symptoms. SLNB at the time of mastectomy did not result in an increased mean weight-adjusted arm volume compared to mastectomy without axillary surgery (p = 0.76). Mastectomy with ALND was associated with a significantly greater mean weight-adjusted arm volume change compared to mastectomy with SLNB (p < 0.0001) and without axillary surgery (p = 0.0028). Patients who underwent mastectomy with ALND more commonly reported symptoms associated with lymphedema compared to those with SLNB or no axillary surgery (p < 0.0001). Patients who underwent mastectomy with SLNB or no axillary surgery reported similar lymphedema symptoms. Addition of SLNB to mastectomy is not associated with a significant increase in measured or self-reported lymphedema rates. Therefore, SLNB may be performed at the time of prophylactic mastectomy without an increased risk of lymphedema.

Sentinel lymph node biopsy in breast cancer: a comprehensive literature review

Sentinel lymph node biopsy has emerged as the new standard of care for nodal staging in early-stage breast disease. In the this review, the procedure of SLNB in breast cancer will be examined in greater detail with the aim of understanding techniques that may improve results and of identifying future research questions in this field.