Sentinel lymph node biopsy during prophylactic mastectomy: Is there a role?

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.

Incidence of Occult Breast Cancer in Carriers of BRCA1/2 or Other High-Penetrance Pathogenic Variants Undergoing Prophylactic Mastectomy: When is Sentinel Lymph Node Biopsy Indicated?

BACKGROUND

This study sought to determine the likelihood of occult malignancy during risk-reducing mastectomy in high-penetrance pathogenic variant carriers to help refine axillary staging recommendations.

METHODS

The authors performed a retrospective cohort study analyzing all female carriers of pathogenic variants in BRCA1/2, PALB2 or other genes who underwent prophylactic surgery at their institution between 2006 and 2021. Occult breast cancer was defined as the unanticipated presence of in situ or invasive malignancy on pathologic evaluation of prophylactic mastectomy specimens.

RESULTS

Of 523 women, 243 carriers met the inclusion criteria for the study including 124 BRCA1 (51.0%), 108 BRCA2 (44.4%), and 11 PALB2, TP53, CDH1, or PTEN (4.6%) carriers. The median age was 44 years (interquartile range, 37-52 years). Overall, 128 women (52.7%) underwent bilateral prophylactic mastectomies, and 115 (47.3%) underwent contralateral prophylactic mastectomy. In the 371 mastectomies performed, 16 (4.3%) occult malignancies were diagnosed. Most of the occult malignancies were ductal carcinoma in situ (13 mastectomies, 3.5%), whereas 3 mastectomies (0.8%) contained invasive breast cancer. If Breast Imaging Reporting and Data System (BIRADS) 1-2 or BIRADS 3 findings were reported on preoperative magnetic resonance imaging (MRI), the rate of occult malignancy decreased to 3.0 and 2.8%, respectively, per mastectomy. The patient-level factors associated with a likelihood of occult breast cancer greater than 10% included a history of prior breast cancer, age exceeding 60 years, and BIRADS 4 findings on preoperative imaging.

CONCLUSIONS

Occult invasive malignancy was detected in less than 1% of the risk-reducing mastectomies performed for women with BRCA1/2 or PALB2 pathogenic variants. Sentinel lymph node biopsy can be safely avoided when BIRADS 1-3 findings are reported on preoperative MRI.

Internal Mammary Lymph Node Biopsy during Microsurgical Breast Reconstruction: A Prospective Study

BACKGROUND

 Accurate assessment of regional lymph node basins is critical for oncological management of breast cancer. The internal mammary lymph node (IMLN) basin directly drains the medial pole of the breast, but biopsy is not commonly performed. While the axillary sentinel lymph node sample remains the standard of care, the majority of patients who have been found to have a positive IMLN biopsy have simultaneously had negative axillary sentinel lymph nodes. This study prospectively examines routine IMLN biopsy during microsurgical breast reconstruction.

METHODS

 An IRB-approved study of routine IMLN biopsies in 270 consecutive patients who underwent microsurgical breast reconstruction was performed from July 1, 2018, to June 1, 2021. Recorded data included unilateral or bilateral breast reconstruction, unilateral or bilateral IMLN sampling, patient demographics, disease stage, and pathologic findings of IMLN.

RESULTS

 The majority of patients, 240 of 270 patients (88.9%), had bilateral reconstruction. Overall, 5 out of 270 (1.9%) patients had positive IMLN; one of these patients had positive axillary sentinel lymph nodes. The IMLN biopsy results in two of the five patients affected the clinical course as they were upstaged and required chemoradiation.

CONCLUSION

 Direct visualization of the internal mammary lymph nodes during dissection of the recipient vessels for microsurgical breast reconstruction allows for convenient sampling, with minimal donor site morbidity and enhances the therapeutic management of patients in whom nodal involvement is present. As such, the authors recommend IMLN sampling.

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.

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.

Sentinel lymph node biopsy in low risk settings

BACKGROUND

Sentinel lymph node biopsy (SLNB) should be performed in patients with ductal carcinoma in situ (DCIS) undergoing mastectomy. Yet, the same logic is controversial in the setting of prophylactic mastectomy.

METHODS

Surgeons were surveyed as to their practices. Statistical analyses were performed to identify associated factors.

RESULTS

238 surgeons responded to the survey. 73.1% of respondents stated they would always perform SLNB in the setting of mastectomy for DCIS, but only 6.6% would always do so in the prophylactic setting. While generally perceived that the rate of SLN positivity in the setting of pure DCIS and prophylactic mastectomy was <5% (96.9% and 99.5%, respectively), 61.8% of surgeons who reported "always" performing SLNB in the setting of DCIS treated with mastectomy stated they "never" performed a SLNB for prophylactic mastectomy.

CONCLUSION

SLNB practice patterns for these low risk settings are disparate. Consensus is required to rationalize practice.

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.

Is Sentinel Lymph Node Biopsy Necessary in Patients Undergoing Prophylactic Mastectomy? A Systematic Review and Meta-Analysis

The gain by performing sentinel lymph node biopsy (SLNB) during prophylactic mastectomy (PM) is debatable, and we performed a meta-analysis of existing literature to evaluate that the role of SLNB in subjects undergoing PM. A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google Scholar, Science Direct, and Web of Science. The search identified 11 relevant articles reporting on patients who underwent SLNB at the time of PM. Data were abstracted from each study and used to calculate a pooled odds ratio (OR) and 95% confidence interval (95% CI). We included 14 studies comprising of 2,708 prophylactic mastectomies. Among 2,708 prophylactic mastectomies, the frequency of occult invasive cancer (51 cases) was 1.8% and the rate of positive SLNs (33 cases) was 1.2%. In 25 invasive cancers at the time of PM were found to have negative SLNs which avoided axillary lymph node dissection (ALND). In seven cases with positive SLNBs were found not to have invasive cancer at the time of PM and needed a subsequent ALND. Most of the patients with positive SLNs had locally advanced disease in the contralateral breast. SLNB may be suitable for patients with ipsilateral, locally advanced breast cancer and is not recommend for all patients undergoing PM.