Contralateral Prophylactic Mastectomy: Factors Predictive of Occult Malignancy or High-Risk Lesion and the Impact of MRI and Genetic Testing

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.

Assessment of the effect of the American Society of Breast Surgery guidelines on contralateral prophylactic mastectomy rates for unilateral breast cancer

BACKGROUND

In July 2016, the American Society of Breast Surgeons published guidelines discouraging contralateral prophylactic mastectomy for average-risk women with unilateral breast cancer. We incorporated these into practice with structured patient counseling and aimed to assess the effect of this initiative on contralateral prophylactic mastectomy rates.

METHODS

We evaluated female patients with unilateral breast cancer undergoing mastectomy at our institution from January 2011 to November 2022. Variables associated with contralateral prophylactic mastectomy and trends over time were analyzed using the Wilcoxon rank sum test or χ2 analysis as appropriate.

RESULTS

Among 3,208 patients, (median age 54 years) 1,366 (43%) had a unilateral mastectomy, and 1,842 (57%) also had a concomitant contralateral prophylactic mastectomy. Across all patients, contralateral prophylactic mastectomy rates significantly decreased post-implementation from 2017 to 2019 (55%) vs 2015 to 2016 (62%) (P = .01) but increased from 2020 to 2022 (61%). Immediate breast reconstruction rate was 70% overall (81% with contralateral prophylactic mastectomy and 56% without contralateral prophylactic mastectomy, P < .001). Younger age, White race, mutation status, and earlier stage were also associated with contralateral prophylactic mastectomy. Genetic testing increased from 27% pre-guideline to 74% 2020 to 2022, as did the proportion of patients with a pathogenic variant (4% pre-guideline vs 11% from 2020-2022, P < .001), of whom 91% had a contralateral prophylactic mastectomy. Among tested patients without a pathogenic variant and patients not tested, contralateral prophylactic mastectomy rates declined from 78% to 67% and 48% to 38% pre -and post-guidelines, respectively, P < .001.

CONCLUSION

Implementation of specific patient counseling was effective in decreasing contralateral prophylactic mastectomy rates. While recognizing that patient choice plays a significant role in the decision for contralateral prophylactic mastectomy, further educational efforts are warranted to affect contralateral prophylactic mastectomy rates, particularly in the setting of negative genetic testing.

Delayed Sentinel Lymph Node Dissection in Patients with a Preoperative Diagnosis of Ductal Cancer In Situ by Preoperative Injection with Superparamagnetic Iron Oxide (SPIO) Nanoparticles: The SentiNot Study

BACKGROUND

Difficulty in preoperatively assessing the risk for occult invasion or surgery that precludes future accurate axillary mapping in patients with ductal cancer in situ (DCIS) account for overutilization of SLND.

METHODS

Prospective, multicenter, cohort study, including women with any DCIS planned for mastectomy or DCIS grade 2 and > 20 mm, any DCIS grade 3, any mass-forming DCIS and any planned surgery. Patients received an interstitial SPIO injection during breast surgery, but no upfront SLND was performed. If invasion was identified on final pathology, delayed SLND (d-SLND) was performed separately with the coadministration of isotope ± blue dye (BD). Study outcomes were proportion of upfront SLNDs that were avoided, detection rates during d-SLND, and impact on healthcare costs.

RESULTS

In total, 78.7% of study participants (N = 254, mean age 60 years, mean DCIS size 37.8 mm) avoided upfront SLND. On d-SLND (median 28 days, range 9-46), SPIO outperformed Tc99 with (98.2% vs. 63.6%, p < 0.001) or without BD (92.7% vs. 50.9%, p < 0.001) and had higher nodal detection rate (86.9% vs. 32.3%, p < 0.001) and with BD (93.9% vs. 41.4%, p < 0.001). Only 27.9% of all SLNs retrieved were concordant for Tc99 and SPIO. Type of breast procedure (WLE vs. oncoplastic BCT vs. mastectomy) affected these outcomes and accounted for the low performance of Tc99 (p < 0.001). d-SLND resulted in a 28.1% total cost containment for women with pure DCIS on final pathology (4190 vs. 5828 USD, p < 0.001).

CONCLUSIONS

Marking the SLN with SPIO may avoid overtreatment and allow for accurate d-SLND in patients with DCIS.

Comprehensive Care of Women With Genetic Predisposition to Breast and Ovarian Cancer

Women at risk for hereditary breast and ovarian cancer syndromes are frequently seen in primary care and gynecology clinics. They present with a distinctive set of clinical and emotional needs that revolve around complex risk management discussions and decision making. The care of these women calls for the creation of individualized care plans that facilitate adjustment to the mental and physical changes associated with their choices. This article provides an update on comprehensive evidence-driven care of women with hereditary breast and ovarian cancer. The aim of this review is to aid clinicians in identifying those at risk for hereditary cancer syndromes and provide practical advice on patient-centered medical and surgical risk management. Topics of discussion include enhanced surveillance, preventive medications, risk-reducing mastectomy and reconstruction, risk-reducing bilateral salpingo-oophorectomy, fertility, sexuality, and menopausal management, with attention to the importance of psychological support. High-risk patients may benefit from a multidisciplinary team that provides realistic expectations with consistent messaging. The primary care provider must be aware of the special needs of these patients and the consequences of their risk management interventions.

Prophylactic mastectomy and occult malignancy: Surgical and imaging considerations

BACKGROUND

Sentinel node biopsy (SLNB) is not routinely recommended for patients undergoing prophylactic mastectomy (PM), yet omission remains a subject of debate among surgeons. A modern patient cohort was examined to determine occult malignancy (OM) incidence within PM specimens to reinforce current recommendations.

METHODS

All PM performed over a 5-year period were retrospectively identified, including women with unilateral breast cancer who underwent synchronous or delayed contralateral PM or women with elevated cancer risk who underwent bilateral PM.

RESULTS

The study population included 772 patients (598 CPM, 174 BPM) with a total of 39 OM identified: 17 invasive cancers (14 CPM, 3 BPM) and 22 DCIS (19 CPM, 3 BPM). Of the 86 patients for whom SLNB was selectively performed, 1 micrometastasis was identified. In the CPM cohort, risk of OM increased with age, presence of LCIS of either breast, or presence of a non-BRCA high-penetrance gene mutation, while preoperative magnetic resonance imaging was associated with lower likelihood of OM.

CONCLUSIONS

Given the low incidence of invasive OM in this updated series, routine SLNB is of low value for patients undergoing PM. For patients with indeterminate radiographic findings, discordant preoperative biopsies, LCIS, or non-BRCA high-penetrance gene mutations, selective SLNB implementation could be considered.

[Prophylactic mastectomy and occult cancer: a ten-year experience at a cancer center]

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.

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.

A standard mastectomy should not be the only recommended breast surgical treatment for non-metastatic inflammatory breast cancer: A large population-based study in the Surveillance, Epidemiology, and End Results database 18

BACKGROUND

Standard mastectomy has long been the recommended breast surgical treatment for non-metastatic inflammatory breast cancer (IBC). The objective of this population-based study was to evaluate the significance of various breast surgical treatments for this highly aggressive subtype.

METHODS

The Surveillance, Epidemiology, and End Results program registry was searched to identify women with non-metastatic IBC receiving standard treatment including breast surgery, radiation therapy and chemotherapy diagnosed between 1998 and 2013. Comparisons of the proportions of various breast surgery procedures over the years were performed using Pearson's chi-square test. Breast cancer-specific survival (BCSS) and overall survival (OS) were estimated using the Kaplan-Meier product limit method and compared across groups using the log-rank statistic. Cox models were then fitted to compare the association between various breast surgical procedures and BCSS or OS after adjusting for patient and tumor characteristics.

RESULTS

A total of 3374 cases were identified. Over the years, the proportion of contralateral prophylactic mastectomy (CPM), breast reconstruction and both were increasing. The proportion of implant-based reconstruction was also increasing with no difference in survival compared with other types of reconstruction. There was no statistically significant difference in BCSS or OS among various breast surgery treatments, such as breast conserving surgery, CPM, breast reconstruction and standard unilateral mastectomy.

CONCLUSIONS

Breast surgery is of great significance to the clinical outcome of IBC. Standard mastectomy should not be the only recommended breast surgical treatment.

Contralateral Prophylactic Mastectomy for Women with T4 Locally Advanced Breast Cancer

BACKGROUND

The use of contralateral prophylactic mastectomy (CPM) for women with unilateral breast cancer is increasing. The authors were interested in assessing whether this trend extended to patients with T4 disease.

METHODS

We identified 92 patients from our prospective breast surgery registry with unilateral clinical T4 M0 disease who underwent mastectomy at our institution from October 2008 to July 2015. Patient, tumor, and treatment variables were compared between patients who did and those who did not undergo CPM, and the reasons patients elected CPM were ascertained.

RESULTS

Of the 92 patients, 33 (36 %) underwent a CPM, including 25 of 55 patients (45 %) with inflammatory breast cancer. Immediate breast reconstruction was performed for 11 of the 92 patients (12 %), including 4 CPM patients. Pathology showed benign findings in all 33 CPM cases, including 3 patients with atypical hyperplasia. The primary reason for CPM reported by the patients included fear of occult current or future breast cancer in 12 cases (36 %), symmetry in 11 cases (33 %), avoidance of future chemotherapy in 5 cases (15 %), deleterious BRCA mutation in 2 cases (6 %), contralateral benign breast disease in 2 cases (6 %), and medical oncologist recommendation in 1 cases (3 %). Patients selecting CPM were younger and more likely to have undergone BRCA testing.

CONCLUSIONS

A substantial rate of CPM was observed among women undergoing mastectomy for unilateral T4 breast cancer despite the considerable risk of mortality from their index cancer. The reasons for selection of CPM paralleled those reported for patients with early-stage disease. The most common motivation was fear of occult current or future breast cancer and included the desire to avoid further chemotherapy.