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.

Lobular-Like Features and Outcomes of Mixed Invasive Ductolobular Breast Cancer (MIDLC): Insights from 54,403 Stage I-III MIDLC Patients

BACKGROUND

Mixed invasive ductolobular breast cancer (MIDLC) is a rare histological subtype of breast cancer (BC), with components of both invasive ductal cancer (IDC) and invasive lobular cancer (ILC). Its clinicopathological features and outcomes have not been well characterized.

METHOD

The National Cancer Database 2010-2017 was reviewed to identify women with stage I-III BCs. Univariate analysis was performed using Chi-square or Wilcoxon rank-sum tests and multivariable analysis with logistic regression to predict surgical decisions. Survival was assessed using multivariable Cox proportional hazards regression analysis.

RESULTS

We identified 955,828 women with stage I-III BCs (5.7% MIDLC, 10.3% ILC, and 84.0% IDC). MIDLC was more like ILC than IDC in terms of multicentricity (14.2% MIDLC, 13.0% ILC, 10.0% IDC), hormone receptor positivity (96.6% MIDLC, 98.2% ILC, 81.2% IDC), and use of neoadjuvant chemotherapy (NAC; 5.8% MIDLC, 5.2% ILC, 10.8% IDC). 744,607 women underwent upfront surgery. The mastectomy rates were 42.3% for MIDLC, 46.5% for ILC, and 33.3% for IDC (all p < 0.001). With 5.5 years of median follow-up, the adjusted overall survival in the upfront surgery hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) biological subgroup was better in MIDLC (hazard ratio 0.88, p < 0.001) and ILC (hazard ratio 0.91, p < 0.001) than in IDC. Like ILC, MIDLC also had a lower pathological complete response to NAC than IDC (12.3% MIDLC, 7.3% ILC, 28.6% IDC).

CONCLUSIONS

MIDLC displays a mixed pattern of characteristics favoring features of ILC compared with IDC, with favorable 5-year overall survival compared with IDC within the HR+/HER2- subtype who underwent upfront surgery.

Benign Breast Disease and Breast Cancer Risk in the Percutaneous Biopsy Era

Importance

Benign breast disease (BBD) comprises approximately 75% of breast biopsy diagnoses. Surgical biopsy specimens diagnosed as nonproliferative (NP), proliferative disease without atypia (PDWA), or atypical hyperplasia (AH) are associated with increasing breast cancer (BC) risk; however, knowledge is limited on risk associated with percutaneously diagnosed BBD.

Objectives

To estimate BC risk associated with BBD in the percutaneous biopsy era irrespective of surgical biopsy.

Design, Setting, and Participants

In this retrospective cohort study, BBD biopsy specimens collected from January 1, 2002, to December 31, 2013, from patients with BBD at Mayo Clinic in Rochester, Minnesota, were reviewed by 2 pathologists masked to outcomes. Women were followed up from 6 months after biopsy until censoring, BC diagnosis, or December 31, 2021.

Exposure

Benign breast disease classification and multiplicity by pathology panel review.

Main Outcomes

The main outcome was diagnosis of BC overall and stratified as ductal carcinoma in situ (DCIS) or invasive BC. Risk for presence vs absence of BBD lesions was assessed by Cox proportional hazards regression. Risk in patients with BBD compared with female breast cancer incidence rates from the Iowa Surveillance, Epidemiology, and End Results (SEER) program were estimated.

Results

Among 4819 female participants, median age was 51 years (IQR, 43-62 years). Median follow-up was 10.9 years (IQR, 7.7-14.2 years) for control individuals without BC vs 6.6 years (IQR, 3.7-10.1 years) for patients with BC. Risk was higher in the cohort with BBD than in SEER data: BC overall (standard incidence ratio [SIR], 1.95; 95% CI, 1.76-2.17), invasive BC (SIR, 1.56; 95% CI, 1.37-1.78), and DCIS (SIR, 3.10; 95% CI, 2.54-3.77). The SIRs increased with increasing BBD severity (1.42 [95% CI, 1.19-1.71] for NP, 2.19 [95% CI, 1.88-2.54] for PDWA, and 3.91 [95% CI, 2.97-5.14] for AH), comparable to surgical cohorts with BBD. Risk also increased with increasing lesion multiplicity (SIR: 2.40 [95% CI, 2.06-2.79] for ≥3 foci of NP, 3.72 [95% CI, 2.31-5.99] for ≥3 foci of PDWA, and 5.29 [95% CI, 3.37-8.29] for ≥3 foci of AH). Ten-year BC cumulative incidence was 4.3% for NP, 6.6% for PDWA, and 14.6% for AH vs an expected population cumulative incidence of 2.9%.

Conclusions and Relevance

In this contemporary cohort study of women diagnosed with BBD in the percutaneous biopsy era, overall risk of BC was increased vs the general population (DCIS and invasive cancer combined), similar to that in historical BBD cohorts. Development and validation of pathologic classifications including both BBD severity and multiplicity may enable improved BC risk stratification.

ASO Author Reflections: Toward Individualized Management of Heterogenous Mixed Invasive Ductolobular Breast Cancers

Mixed invasive ductolobular breast cancer (MIDLC) is a rare breast cancer with varying lobular and ductal components. Characteristics, management, and outcomes of MIDLC are not well understood due to the rarity of the cancer and the lack of uniform diagnostic criteria and reporting. There is a need for better understanding and individualized management of this heterogeneous spectrum of breast cancers.

Presurgical Oral Tamoxifen vs Transdermal 4-Hydroxytamoxifen in Women With Ductal Carcinoma In Situ: A Randomized Clinical Trial

Importance

Oral tamoxifen citrate benefits women with ductal carcinoma in situ (DCIS), but concern about toxic effects has limited acceptance. Previous pilot studies have suggested transdermal 4-hydroxytamoxifen gel has equivalent antiproliferative efficacy to oral tamoxifen, with low systemic exposure.

Objective

To demonstrate that 4-hydroxytamoxifen gel applied to the breast skin is noninferior to oral tamoxifen in its antiproliferative effect in DCIS lesions.

Design, Setting, and Participants

This randomized, double-blind, phase 2 preoperative window trial was performed at multicenter breast surgery referral practices from May 31, 2017, to January 27, 2021. Among 408 women with estrogen receptor-positive DCIS who were approached, 120 consented and 100 initiated study treatment. The most common reasons for nonparticipation were surgical delay, disinterest in research, and concerns about toxic effects. Data were analyzed from January 26, 2021, to October 5, 2022.

Intervention

Random assignment to oral tamoxifen citrate, 20 mg/d, and gel placebo or 4-hydroxytamoxifen gel, 2 mg/d per breast, and oral placebo, for 4 to 10 weeks, followed by DCIS resection.

Main Outcomes and Measures

The primary end point was absolute change in DCIS Ki-67 labeling index (Ki67-LI). Secondary end points included 12-gene DCIS Score, breast tissue tamoxifen metabolite concentrations, tamoxifen-responsive plasma protein levels, and patient-reported symptoms. Noninferiority of Ki67-LI reduction by 4-hydroxytamoxifen gel was tested using analysis of covariance; within- and between-arm comparisons were performed with paired t tests for mean values or the Wilcoxon rank sum test for medians.

Results

Of 90 participants completing treatment (mean [SD] age, 55 [11] years; 8 [8.9%] Asian, 16 [17.8%] Black, 8 [8.9%] Latina, and 53 [58.9%] White), 15 lacked residual DCIS in the surgical sample, leaving 75 evaluable for the primary end point analysis (40 in the oral tamoxifen group and 35 in the 4-hydroxytamoxifen gel group). Posttreatment Ki67-LI was 3.3% higher (80% CI, 2.1%-4.6%) in the 4-hydroxytamoxifen gel group compared with the oral tamoxifen group, exceeding the noninferiority margin (2.6%). The DCIS Score decreased more with oral tamoxifen treatment (-16 [95% CI, -22 to -9.4]) than with 4-hydroxytamoxifen gel (-1.8 [95% CI, -5.8 to 2.3]). The median 4-hydroxytamoxifen concentrations deep in the breast were nonsignificantly higher in the oral tamoxifen group (5.7 [IQR, 4.0-7.9] vs 3.8 [IQR, 1.3-7.9] ng/g), whereas endoxifen was abundant in the oral tamoxifen group and minimal in the 4-hydroxytamoxifen gel group (median, 13.0 [IQR, 8.9-20.6] vs 0.3 [IQR, 0-0.3] ng/g; P < .001). Oral tamoxifen caused expected adverse changes in plasma protein levels and vasomotor symptoms, with minimal changes in the transdermal group.

Conclusions and Relevance

In this randomized clinical trial, antiproliferative noninferiority of 4-hydroxytamoxifen gel to oral tamoxifen was not confirmed, potentially owing to endoxifen exposure differences. New transdermal approaches must deliver higher drug quantities and/or include the most potent metabolites.

Trial Registration

ClinicalTrials.gov Identifier: NCT02993159.

The Benefits of Local Anesthesia Used in Mastectomy Without Reconstruction

BACKGROUND

The opioid epidemic has driven renewed interest in local anesthesia to reduce postoperative opioid use. Our objective was to determine if local anesthesia decreased hospital pain scores, oral morphine equivalents (OME), length of stay (LOS), and nausea/vomiting.

METHODS

Single institution retrospective study of females who underwent mastectomy without reconstruction.

RESULTS

Overall, 712 patients were included; 63 (8.8%) received bupivacaine (B), 512 (72%) liposomal bupivacaine (LB), and 137 (19%) no local. 95% were discharged on POD1. Liposomal bupivacaine use increased from 2014 to 2019. Additional factors associated with use of local regimen were surgeon and extent of axillary surgery. Fewer patients used postop opioids during their hospital stay if any local was used compared to none (76 vs 88%; 0.003). Compared to none, local had shorter mean PACU LOS (95 vs 87 min; P = .02), lower mean intraoperative-OME (96 vs 106; P < .001), and lower mean postoperative OME/hr (1.4 vs 1.8 P = .001). Multivariable analysis (MVA) showed lower OME/hr with LB compared to B and none (P = .002); this translates to 22 mg and 30 mg of oxycodone in a 24-hr period, respectively. MVA showed lower POD1 pain scores with LB relative to none (P = .049). Local did not impact nausea/emesis.

CONCLUSION

Local anesthesia was superior to no local in several measures. However, a consistent benefit of a specific local anesthetic agent was not demonstrated (LB vs B). A prospective study is warranted to determine the optimal local regimen for this cohort and further inform clinical relevance.

Trimodality Therapy Improves Disease Control in Radiation-Associated Angiosarcoma of the Breast

PURPOSE

To evaluate the impact of trimodality treatment versus monotherapy or dual therapy for radiation-associated angiosarcoma of the breast (RAASB) after prior breast cancer treatment.

EXPERIMENTAL DESIGN

With Institutional Review Board approval, we identified patients diagnosed with RAASB and abstracted data on disease presentation, treatment, and oncologic outcomes. Trimodality therapy included (i) taxane induction, (ii) concurrent taxane/radiation, and then (iii) surgical resection with wide margins.

RESULTS

A total of 38 patients (median age 69 years) met inclusion criteria. Sixteen received trimodality therapy and 22 monotherapy/dual therapy. Skin involvement and disease extent were similar in both groups. All trimodality patients required reconstructive procedures for wound closure/coverage, compared with 48% of monotherapy/dual therapy patients (P < 0.001). Twelve of 16 (75%) patients receiving trimodality therapy had a pathologic complete response (pCR). With median follow-up of 5.6 years, none had local recurrence, 1 patient (6%) had distant recurrence, and no patients died. Among 22 patients in the monotherapy/dual therapy group, 10 (45%) had local recurrence, 8 (36%) had distant recurrence, and 7 (32%) died of disease. Trimodality therapy demonstrated significantly better 5-year recurrence-free survival [RFS; 93.8% vs. 42.9%; P = 0.004; HR, 7.6 (95% confidence interval, CI: 1.3-44.2)]. Combining all patients with RAASB regardless of treatment, local recurrence was associated with subsequent distant recurrence (HR, 9.0; P = 0.002); distant recurrence developed in 3 of 28 (11%) patients without local recurrence compared with 6 of 10 (60%) with local recurrence. The trimodality group had more surgical complications that required reoperation or prolonged healing.

CONCLUSIONS

Trimodality therapy for RAASB was more toxic but is promising, with a high rate of pCR, durable local control, and improved RFS.

Long-term outcomes of intraoperatively-placed applicator brachytherapy for rapid completion of breast conserving treatment: An analysis of a prospective registry data

Background and purpose

To evaluate the long-term outcome of accelerated partial breast irradiation utilizing intraoperatively placed applicator-based brachytherapy (ABB) in early-stage breast cancer.

Materials and methods

From our prospective registry, 223 patients with pTis-T2, pN0/pN1mic breast cancer were treated with ABB. The median treatment duration including surgery and ABB was 7 days. The prescribed doses were 32 Gy/8 fx BID (n = 25), 34 Gy/10 fx BID (n = 99), and 21 Gy/3 fx QD (n = 99). Endocrine therapy (ET) adherence was defined as completion of planned ET or ≥ 80% of the follow-up (FU) period. Cumulative incidence of ipsilateral breast tumor recurrence (IBTR) was estimated and influencing factors for IBTR-free survival rate (IBTRFS) were analyzed.

Results

218/223 patients had hormone receptor-positive tumors, including 38 (17.0%) with Tis and 185 (83.0%) with invasive cancer. After a median FU of 63 months, 19 (8.5%) patients had recurrence [17 (7.6%) with an IBTR]. Rates of 5-year IBTRFS and DFS were 92.2% and 91.1%, respectively. The 5-year IBTRFS rates were significantly higher for post-menopausal women (93.6% vs. 66.4%, p = 0.04), BMI < 30 kg/m2 (97.4% vs. 88.1%, p = 0.02), and ET-adherence (97.5% vs. 88.6%, p = 0.02). IBTRFS did not differ with dose regimens.

Conclusions

Postmenopausal status, BMI < 30 kg/m2, and ET- adherence predicted favorable IBTRFS. Our results highlight the importance of careful patient selection for ABB and encouragement of ET compliance.

Abstract 4213: Comparison of benign breast disease subtypes and breast cancer risk among Hispanic and non-Hispanic white women in New Mexico

Introduction: Benign breast disease (BBD) is an important breast cancer (BC) risk factor, which may be classified as non-proliferative disease (NPD), proliferative disease without atypia (PDWA), or atypical hyperplasia (AH) for risk stratification. Data related to the frequency of specific types of BBD and their relationship to BC risk in the Hispanic American population are limited. To address this knowledge gap, we compared BBD and associated BC risk among Hispanic white (HW) and non-Hispanic white (NHW) in New Mexico (NM).

Methodology: A retrospective IRB-approved study was performed of women 19 years or older residing in six counties in NM (Bernalillo, Sandoval, Sante Fe, Socorro, Torrance, Cibola/Valencia) between 1996 and mid-2007 to compare the frequency of BBD subtypes and BC risk among HW and NHW. We excluded women who had a history of BC prior to BBD diagnosis or who were diagnosed with BC within 6 months after BBD biopsy. Race and ethnicity were self-reported by women at the time of biopsy. BBD was categorized as NPD, PDWA, or AH based on medical records. Incident BC (in-situ or invasive) was ascertained via linkage to the NM Surveillance Epidemiology End Results (SEER) Registry and BC risk was assessed using standardized incidence ratios (SIRs), comparing the observed number of BC events to that expected based on the NM SEER six-county race- and ethnicity-specific incidence rates, accounting for age and calendar period.

Results: Our analysis included 3,870 HW and 6,996 NHW women with BBD. The HW were younger (47.1 vs. 51 years) compared to NHW. HW women had slightly more NPD (69.4% vs. 66.6%) but less PDWA (26.2% vs. 29.4%) and similar frequency of AH (4.3% vs. 3.9%) as compared to NHW. Over a median post-BBD follow-up period of 13 years (range 6 months-17 years), 644 BCs were observed (4.81% in HW and 6.55% in NHW). The observed BC risk among women with BBD was higher than population-based expected rates (SIR 1.98, 95% CI 1.82-2.13, p&lt;0.001) and showed expected increases in risk with increasing degrees of BBD abnormality: SIR=1.90 for NPD, 2.00 for PDWA, and 3.01 for AH. Comparing BC risk by ethnic subgroups, HW women had an overall risk of BC after BBD that was statistically indistinguishable from NHW women (SIR=2.17, 95% CI 1.86-2.48 in HW women, and SIR=1.91, 95% CI 1.73-2.08 in NHW women). Within the major subgroups of the BBD findings, there were no significant differences in risk of BC after BBD for HW versus NHW women.

Conclusions: In this population-based study, benign breast disease subtypes and their associated breast cancer risk were similar among the Hispanic and non-Hispanic white women.

Citation Format: Kush Raj Lohani, Andrea M. Nibbe, Robert A. Vierkant, Laura M. Pacheco-Spann, Lisa R. Seymour, Celine M. Vachon, Mark E. Sherman, Amy C. Degnim, Deirdre Hill. Comparison of benign breast disease subtypes and breast cancer risk among Hispanic and non-Hispanic white women in New Mexico. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4213.

Benign Breast Disease, NSAIDs, and Postmenopausal Breast Cancer Risk in the CPS-II Cohort

ABSTRACT

Nonsteroidal anti-inflammatory agents (NSAID) are associated with modest inconsistent reductions in breast cancer risk in population-based cohorts, whereas two focused studies of patients with benign breast disease (BBD) have found lower risk with NSAID use. Given that BBD includes fibroinflammatory lesions linked to elevated breast cancer risk, we assessed whether NSAID use was associated with lower breast cancer risk among patients with BBD.Participants were postmenopausal women in the Cancer Prevention Study-II (CPS-II), a prospective study of cancer incidence and mortality, who completed follow-up surveys in 1997 with follow-up through June 30, 2015. History of BBD, NSAID use, and covariate data were updated biennially. This analysis included 23,615 patients with BBD and 36,751 patients with non-BBD, including 3,896 incident breast cancers over an average of 12.72 years of follow-up among participants. NSAID use, overall and by formulation, recency, duration, and pills per month was analyzed versus breast cancer risk overall and by BBD status using multivariable-adjusted Cox models; BBD status and NSAID use were modeled as time-dependent exposures.Patients with BBD who reported using NSAIDs experienced lower breast cancer risk (HR, 0.87; 95% CI, 0.78-0.97), with similar effects for estrogen receptor (ER)-positive breast cancers [HR, 0.85; 95% confidence interval (CI), 0.74-0.97] and ER-negative breast cancers (HR, 0.87; 95% CI, 0.59-1.29); among women without BBD, NSAID use was unrelated to risk (HR, 1.02; 95% CI, 0.92-1.13; Pinteraction = 0.04). Associations stratified by age, obesity, menopausal hormone use, and cardiovascular disease were similar.Among patients with BBD, NSAID use appears linked to lower breast cancer risk. Further studies to assess the value of NSAID use among patients with BBD are warranted.

PREVENTION RELEVANCE

We examined whether NSAID use, a modifiable exposure, is associated with breast cancer risk in postmenopausal women from the Cancer Prevention Study-II with self-reported benign breast disease, an often inflammatory condition associated with higher rates of breast cancer.

Immune cells are increased in normal breast tissues of BRCA1/2 mutation carriers

PURPOSE

Breast cancer risk is elevated in pathogenic germline BRCA 1/2 mutation carriers due to compromised DNA quality control. We hypothesized that if immunosurveillance promotes tumor suppression, then normal/benign breast lobules from BRCA carriers may demonstrate higher immune cell densities.

METHODS

We assessed immune cell composition in normal/benign breast lobules from age-matched women with progressively increased breast cancer risk, including (1) low risk: 19 women who donated normal breast tissue to the Komen Tissue Bank (KTB) at Indiana University Simon Cancer Center, (2) intermediate risk: 15 women with biopsy-identified benign breast disease (BBD), and (3) high risk: 19 prophylactic mastectomies from women with germline mutations in BRCA1/2 genes. We performed immunohistochemical stains and analysis to quantitate immune cell densities from digital images in up to 10 representative lobules per sample. Median cell counts per mm2 were compared between groups using Wilcoxon rank-sum tests.

RESULTS

Normal/benign breast lobules from BRCA carriers had significantly higher densities of immune cells/mm2 compared to KTB normal donors (all p < 0.001): CD8 + 354.4 vs 150.9; CD4 + 116.3 vs 17.7; CD68 + 237.5 vs 57.8; and CD11c + (3.5% vs 0.4% pixels positive). BBD tissues differed from BRCA carriers only in CD8 + cells but had higher densities of CD4 + , CD11c + , and CD68 + immune cells compared to KTB donors.

CONCLUSIONS

These preliminary analyses show that normal/benign breast lobules of BRCA mutation carriers contain increased immune cells compared with normal donor breast tissues, and BBD tissues appear overall more similar to BRCA carriers.

Radiation-associated angiosarcoma of the breast with initial presentation as non-mass enhancement on MRI

Radiation-associated angiosarcoma of the breast (RAASB) is a rare and aggressive malignancy occurring after radiation therapy as part of breast cancer treatment. RAASB usually presents several years after prior radiation and typically involves the skin with or without involvement of the parenchyma. Most RAASB are detected as cutaneous changes on physical exam. Herein, we present a unique case of a clinically occult RAASB diagnosed as non-mass enhancement on annual surveillance breast MRI.

Quality control recommendations for RNASeq using FFPE samples based on pre-sequencing lab metrics and post-sequencing bioinformatics metrics

Background

Formalin-fixed, paraffin-embedded (FFPE) tissues have many advantages for identification of risk biomarkers, including wide availability and potential for extended follow-up endpoints. However, RNA derived from archival FFPE samples has limited quality. Here we identified parameters that determine which FFPE samples have the potential for successful RNA extraction, library preparation, and generation of usable RNAseq data.

Methods

We optimized library preparation protocols designed for use with FFPE samples using seven FFPE and Fresh Frozen replicate pairs, and tested optimized protocols using a study set of 130 FFPE biopsies from women with benign breast disease. Metrics from RNA extraction and preparation procedures were collected and compared with bioinformatics sequencing summary statistics. Finally, a decision tree model was built to learn the relationship between pre-sequencing lab metrics and qc pass/fail status as determined by bioinformatics metrics.

Results

Samples that failed bioinformatics qc tended to have low median sample-wise correlation within the cohort (Spearman correlation < 0.75), low number of reads mapped to gene regions (< 25 million), or low number of detectable genes (11,400 # of detected genes with TPM > 4). The median RNA concentration and pre-capture library Qubit values for qc failed samples were 18.9 ng/ul and 2.08 ng/ul respectively, which were significantly lower than those of qc pass samples (40.8 ng/ul and 5.82 ng/ul). We built a decision tree model based on input RNA concentration, input library qubit values, and achieved an F score of 0.848 in predicting QC status (pass/fail) of FFPE samples.

Conclusions

We provide a bioinformatics quality control recommendation for FFPE samples from breast tissue by evaluating bioinformatic and sample metrics. Our results suggest a minimum concentration of 25 ng/ul FFPE-extracted RNA for library preparation and 1.7 ng/ul pre-capture library output to achieve adequate RNA-seq data for downstream bioinformatics analysis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01355-0.

Node Positivity Among Sonographically Suspicious but FNA-Negative Axillary Nodes

BACKGROUND

Fine needle aspiration (FNA) of sonographically suspicious axillary lymph nodes is helpful to clinically stage patients and guide consideration of neoadjuvant therapy in breast cancer. However, data are limited for suspicious nodes that are FNA negative. Our goal is to compare the frequency of node positivity between patients with negative axillary ultrasound (AUSneg) versus suspicious AUS with negative FNA (FNAneg).

METHODS

With IRB approval, we identified all clinically node-negative (cN0) patients with invasive breast cancer treated with upfront surgery at our tertiary care center between 2016 and 2021. AUS is routinely performed with FNA of suspicious lymph node(s). We compared clinicopathologic characteristics and nodal positivity rates between AUSneg and FNAneg groups.

RESULTS

A total of 1580 cN0 patients with invasive breast cancer were analyzed, including 1240 AUSneg and 340 FNAneg patients. The FNAneg group was younger (median age 59.7 years versus 63.5 years, p < 0.001) and had higher clinical T (cT) category (29.1% versus 21.7% with cT2-cT4 disease, p = 0.005). Final axillary pathologic node positivity did not differ significantly between the AUSneg and FNAneg groups (16.5% versus 19.1%, p = 0.25). Among FNAneg patients, 58/340 (17.1%) had a clip placed, with retrieval confirmed in 28/58 (48.3%). Of the 28 retrieved clipped nodes, 27 were sentinel nodes. Final pathologic nodal status (pN+%) did not differ between patients in whom retrieval of the clipped node was confirmed versus not confirmed (28.6% versus 16.7%, p = 0.28).

CONCLUSIONS

Both patients with sonographically suspicious node(s) and negative FNA and patients with negative AUS have a similarly low chance of positive nodes. Additionally, routine targeted excision of FNA-negative clipped nodes is not warranted.

Towards defining morphologic parameters of normal parous and nulliparous breast tissues by artificial intelligence

BACKGROUND

Breast terminal duct lobular units (TDLUs), the source of most breast cancer (BC) precursors, are shaped by age-related involution, a gradual process, and postpartum involution (PPI), a dramatic inflammatory process that restores baseline microanatomy after weaning. Dysregulated PPI is implicated in the pathogenesis of postpartum BCs. We propose that assessment of TDLUs in the postpartum period may have value in risk estimation, but characteristics of these tissues in relation to epidemiological factors are incompletely described.

METHODS

Using validated Artificial Intelligence and morphometric methods, we analyzed digitized images of tissue sections of normal breast tissues stained with hematoxylin and eosin from donors ≤ 45 years from the Komen Tissue Bank (180 parous and 545 nulliparous). Metrics assessed by AI, included: TDLU count; adipose tissue fraction; mean acini count/TDLU; mean dilated acini; mean average acini area; mean "capillary" area; mean epithelial area; mean ratio of epithelial area versus intralobular stroma; mean mononuclear cell count (surrogate of immune cells); mean fat area proximate to TDLUs and TDLU area. We compared epidemiologic characteristics collected via questionnaire by parity status and race, using a Wilcoxon rank sum test or Fisher's exact test. Histologic features were compared between nulliparous and parous women (overall and by time between last birth and donation [recent birth: ≤ 5 years versus remote birth: > 5 years]) using multivariable regression models.

RESULTS

Normal breast tissues of parous women contained significantly higher TDLU counts and acini counts, more frequent dilated acini, higher mononuclear cell counts in TDLUs and smaller acini area per TDLU than nulliparas (all multivariable analyses p < 0.001). Differences in TDLU counts and average acini size persisted for > 5 years postpartum, whereas increases in immune cells were most marked ≤ 5 years of a birth. Relationships were suggestively modified by several other factors, including demographic and reproductive characteristics, ethanol consumption and breastfeeding duration.

CONCLUSIONS

Our study identified sustained expansion of TDLU numbers and reduced average acini area among parous versus nulliparous women and notable increases in immune responses within five years following childbirth. Further, we show that quantitative characteristics of normal breast samples vary with demographic features and BC risk factors.

Serum hormone levels and normal breast histology among premenopausal women

PURPOSE

Breast terminal duct lobular units (TDLUs) are the main source of breast cancer (BC) precursors. Higher serum concentrations of hormones and growth factors have been linked to increased TDLU numbers and to elevated BC risk, with variable effects by menopausal status. We assessed associations of circulating factors with breast histology among premenopausal women using artificial intelligence (AI) and preliminarily tested whether parity modifies associations.

METHODS

Pathology AI analysis was performed on 316 digital images of H&E-stained sections of normal breast tissues from Komen Tissue Bank donors ages ≤ 45 years to assess 11 quantitative metrics. Associations of circulating factors with AI metrics were assessed using regression analyses, with inclusion of interaction terms to assess effect modification.

RESULTS

Higher prolactin levels were related to larger TDLU area (p < 0.001) and increased presence of adipose tissue proximate to TDLUs (p < 0.001), with less significant positive associations for acini counts (p = 0.012), dilated acini (p = 0.043), capillary area (p = 0.014), epithelial area (p = 0.007), and mononuclear cell counts (p = 0.017). Testosterone levels were associated with increased TDLU counts (p < 0.001), irrespective of parity, but associations differed by adipose tissue content. AI data for TDLU counts generally agreed with prior visual assessments.

CONCLUSION

Among premenopausal women, serum hormone levels linked to BC risk were also associated with quantitative features of normal breast tissue. These relationships were suggestively modified by parity status and tissue composition. We conclude that the microanatomic features of normal breast tissue may represent a marker of BC risk.

Abstract 2203: Towards prediction of breast cancer risk in benign biopsies with high-plex GeoMx spatial protein profiling

Background: Biopsy diagnoses of benign breast disease (BBD) confer a 1.5- to 4-fold increased risk of developing breast cancer (BC) compared with women without BBD. Previously, we reported that decreased numbers of specific immune cell types in lobules of BBD biopsies predicted increased BC risk, suggesting the promise of future tissue biomarker studies to define BC risk markers among BBD patients. Thus, we applied protein-based GeoMx® Digital Spatial Profiling (DSP) to BBD biopsies preceding BC (cases) and to BBD biopsies from cancer-free patients (controls) to identify possible BC risk markers, which we then evaluated in subsequent BC tissues and in surrounding normal lobules of cases.

Methods: Archived pathology slides of BBD biopsies were reviewed and used to guide preparation of TMAs containing 1.0-mm diameter FFPE cores of lobules from an age- and cohort-period-matched set of 91 cases and 88 controls from the Mayo Clinic BBD Cohort. For patients who later developed BC, we prepared TMAs of BC tissue and surrounding mapped normal lobules. We applied GeoMx® DSP (immune and canonical signaling proteins) to both sets of TMAs. Following QC and data normalization, associations of case status with log-transformed biomarker expression in lobules of BBD biopsies were carried out using linear mixed modeling approaches, accounting for multiple ROIs per individual. Biomarkers significantly associated with case status (p&lt;0.05) were further examined in BCs and adjacent normal lobules, using similar approaches.

Results: The mean age at BBD biopsy was 52 years, and at BC diagnosis of cases, 61.4 years (mean time from BBD to BC was 10.2 years). A family history of BC was more frequent among cases (70% versus 43%; chi-square p=0.002). Of 72 biomarkers tested, 46 (64.4%) were evaluable after QC and normalization and 5 were associated with BC risk after adjustment for family history of BC: BCL2 (p=0.005), STING (p=0.006), CD44 (p=0.02), S100 protein (p=0.03) and pan-AKT (p=0.05); each showed higher levels in lobules of BBD biopsies of controls than cases. Three unique patterns appeared when examining these biomarkers across tissue type within cases: for BCL2 (p=5 x 10-9) and STING (p=2 x 10-19), levels were high in both BC and lobules surrounding BC but low in preceding BBD; for GAPDH (p=4 x 10-53) and pan-AKT (p=2 x 10-33), levels were high in BC, low in preceding BBD, and moderate in lobules surrounding BC; and for CD44 (p=2 x 10-6) and S100B (p=2 x 10-49), levels were low in BC, high in lobules surrounding BC and moderate in preceding BBD.

Conclusions: Using a novel TMA of lobules in combination with DSP, we preliminarily identified immune-based and PI3 kinase-related protein biomarkers in BBD biopsies associated with BC risk. In case-only analyses, these markers demonstrated complex differences between lobules in BBD biopsies, subsequent BCs and adjacent normal lobules.

Citation Format: Robert Alan Vierkant, Jodi M. Carter, Stacey J. Winham, Chen Wang, Jennifer M. Kachergus, Ji Shi, Raymond M. Moore, Bryan M. McCauley, Laura M. Pacheco-Spann, E A. Thompson, Derek C. Radisky, Amy C. Degnim, Mark E. Sherman. Towards prediction of breast cancer risk in benign biopsies with high-plex GeoMx spatial protein profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2203.

Abstract 5947: Immune biomarkers in breast tissues of patients with BRCA1/2 mutations, benign breast disease, and normal tissue donors

Introduction: The immune microenvironment of the breast is critical in the development and progression of breast cancer. By analyzing the immune components of breast tissues from patients at varying degrees of breast cancer risk, we may gain enhanced understanding of breast cancer risk and mechanisms of carcinogenesis.

Methods: We compared the immune cell composition in breast lobules of age-matched patients with normal and benign breast disease (BBD) at progressively lower breast cancer risk: 1) 18 women with germline mutations in (BRCA1/2); 2) women at intermediate risk (BBD), and 3) women at normal risk (Komen Tissue Bank- (KTB)). We performed immunohistochemical stains for T lymphocytes (CD4, CD8); dendritic cells (CD11c); B lymphocytes (CD20) and macrophages (CD68) and quantitated immune cell densities in up to 10 representative lobules per sample.

Results: The median age of all groups was 43.8 years (range: 34-67). BRCA carriers and BBD patients had a higher percentage of fibrocystic lobules (50% fibrocystic) compared to KTB samples (15% fibrocystic), p&lt;0.001. BRCA carriers had significantly higher densities of CD4, CD8, CD11c, and CD68 positive immune cells compared to KTB donor breast tissues, see Table. Compared with BBD patients, mutation carriers had higher densities of CD8+ cells and suggestively higher CD4+ cells, with similar results for other markers assessed.

Conclusions: Preliminarily, these data showed that benign prophylactic breast tissues from BRCA mutation carriers contain increased numbers of several immune cell types versus tissues from patients at lower breast cancer risk, including BBD patients and research tissue donors. Further investigation is needed to confirm and expand these findings in relation to breast cancer risk.

Table: Pairwise Wilcoxon rank-sum p-values comparing immune cell densities in breast lobules from women with BRCA germline mutations, vs BBD and KTB groups. All Lobules BRCA BBD KTB BRCA vs BBD BRCA vs KTB Median Median Median p-value p-value (IQR) (IQR) (IQR) CD4+, cells/mm2 116.3 63.8 17.7 0.08 &lt;0.001 (46.4-183.6) (25.0-121.1) (13.3-40.6) CD8+, cells/mm2 354.4 200 150.9 0.01 &lt;0.001 (285.5-473.2) (118.9-385) (110.1-225.0) CD11c+, % pp 3.5 3.4 0.4 0.66 &lt;0.001 (1.9-6.8) (1.6-4.7) (0-0.6) CD20+, cells/mm2 6.2 16.7 0 0.16 0.65 (0-25.4) (0-58.3) (0-20.8) CD68, cells/mm2 237.5 219 57.8 0.99 &lt;0.001 (122.9-281.8) (75.0-459.4) (29.2-100.0) IQR - Interquartile Range pp - pixel positive

Citation Format: Joshua W. Ogony, Tanya L. Hoskin, Melody L. Stallings Mann, Stacey J. Winham, Rushin Brahmbhatt, Muhammad Asad Arshad, Alvaro Pena Jimenez, Teresa M. Allers, Mark E. Sherrman, Daniel W. Visscher, Derek C. Radisky, Amy C. Degnim. Immune biomarkers in breast tissues of patients with BRCA1/2 mutations, benign breast disease, and normal tissue donors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5947.

Sexual Well-Being After Nipple-Sparing Mastectomy: Does Preservation of the Nipple Matter?

INTRODUCTION

The primary aim of this study was to evaluate patient-reported outcome measures in patients undergoing mastectomy with and without breast reconstruction (immediate or delayed) with and without nipple preservation.

METHODS

All female patients undergoing mastectomy between 2011 and 2015 at Mayo Clinic Rochester were identified and were mailed the BREAST-Q survey. Breast satisfaction, psychosocial well-being, and sexual well-being were evaluated and compared by surgery type using Wilcoxon rank-sum tests for univariate analysis and linear regression for multivariable analysis adjusting for potential confounders.

RESULTS

Of 1547 patients, 771 completed the BREAST-Q survey (response rate 50%). Of these 771 respondents, 237 (31%) did not have reconstruction, 198 (26%) had nipple-sparing mastectomy with reconstruction (NSM), and 336 (44%) had skin-sparing mastectomy with reconstruction (SSM) ± nipple-areolar complex (NAC) reconstruction (via surgery ± tattoo). Patients with breast reconstruction had consistently higher BREAST-Q scores versus those without. Comparing NSM with all SSMs, there was no difference in satisfaction with breasts (mean 71.8 vs. 70.2, p = 0.21) or psychosocial well-being (mean 81.9 vs. 81.3, p = 0.47); however, sexual well-being was significantly higher in the NSM group on univariate (mean 64.5 vs. 58.0, p = 0.002) and multivariable (β = -4.69, p = 0.03) analysis. Sexual well-being scores were similar for NSM and the SSM subgroups with any type of NAC reconstruction.

CONCLUSIONS

This study demonstrates that NSM positively impacts patient sexual well-being after breast reconstruction compared with SSM, particularly SSM without nipple reconstruction or tattoo. SSM with any type of NAC reconstruction achieved similar satisfaction and sexual well-being to those undergoing NSM.

The breast tissue microbiome, stroma, immune cells and breast cancer

BACKGROUND

Stromal and immune cell composition alterations in benign breast tissue associate with future cancer risk. Pilot data suggest the innate microbiome of normal breast tissue differs between women with and without breast cancer. Microbiome alterations might explain tissue microenvironment variations associated with disease status.

METHODS

Prospectively-collected sterile normal breast tissues from women with benign (n=16) or malignant (n=17) disease underwent 16SrRNA sequencing with Illumina MiSeq and Hybrid-denovo pipeline processing. Breast tissue was scored for fibrosis and fat percentages and immune cell infiltrates (lobulitis) classified as absent/mild/moderate/severe. Alpha and beta diversity were calculated on rarefied OTU data and associations analyzed with multiple linear regression and PERMANOVA.

RESULTS

Breast tissue stromal fat% was lower and fibrosis% higher in benign disease versus cancer (median 30% versus 60%, p=0.01, 70% versus 30%, p=0.002, respectively). The microbiome varied with stromal composition. Alpha diversity (Chao1) correlated with fat% (r=0.38, p=0.02) and fibrosis% (r=-0.32, p=0.05) and associated with different microbial populations as indicated by beta diversity metrics (weighted UniFrac, p=0.08, fat%, p=0.07, fibrosis%). Permutation testing with FDR control revealed taxa differences for fat% in Firmicutes, Bacilli, Bacillales, Staphylococcaceae and genus Staphylococcus, and fibrosis% in Firmicutes, Spirochaetes, Bacilli, Bacillales, Spirochaetales, Proteobacteria RF32, Sphingomonadales, Staphylococcaceae, and genera Clostridium, Staphylococcus, Spirochaetes, Actinobacteria Adlercreutzia. Moderate/severe lobulitis was more common in cancer (73%) than benign disease (13%), p=0.003, but no significant microbial associations were seen.

CONCLUSION

These data suggest a link between breast tissue stromal alterations and its microbiome, further supporting a connection between the breast tissue microenvironment and breast cancer.

Automated quantification of levels of breast terminal duct lobular (TDLU) involution using deep learning

Convolutional neural networks (CNNs) offer the potential to generate comprehensive quantitative analysis of histologic features. Diagnostic reporting of benign breast disease (BBD) biopsies is usually limited to subjective assessment of the most severe lesion in a sample, while ignoring the vast majority of tissue features, including involution of background terminal duct lobular units (TDLUs), the structures from which breast cancers arise. Studies indicate that increased levels of age-related TDLU involution in BBD biopsies predict lower breast cancer risk, and therefore its assessment may have potential value in risk assessment and management. However, assessment of TDLU involution is time-consuming and difficult to standardize and quantitate. Accordingly, we developed a CNN to enable automated quantitative measurement of TDLU involution and tested its performance in 174 specimens selected from the pathology archives at Mayo Clinic, Rochester, MN. The CNN was trained and tested on a subset of 33 biopsies, delineating important tissue types. Nine quantitative features were extracted from delineated TDLU regions. Our CNN reached an overall dice-score of 0.871 (±0.049) for tissue classes versus reference standard annotation. Consensus of four reviewers scoring 705 images for TDLU involution demonstrated substantial agreement with the CNN method (unweighted κappa = 0.747 ± 0.01). Quantitative involution measures showed anticipated associations with BBD histology, breast cancer risk, breast density, menopausal status, and breast cancer risk prediction scores (p < 0.05). Our work demonstrates the potential to improve risk prediction for women with BBD biopsies by applying CNN approaches to generate automated quantitative evaluation of TDLU involution.

Primary tumor resection in patients with stage IV breast cancer: 10-year experience

The role of surgery in the management of stage IV breast cancer is controversial. Existing studies in Stage IV breast cancer have not closely evaluated the role of patient response to induction systemic therapy (IST) in its relationship to survival outcomes. We identified all patients with a diagnosis of de novo stage IV breast cancer who underwent surgery of their primary tumor from January 2008 to December 2018. Patients were grouped according to their response in the primary disease site into progression (progressive primary disease) or no progression (nonprogressive primary; comprising complete, partial and stable response). We identified a total of 45 stage IV breast cancer patients who underwent operative intervention of their primary breast tumor. Prior to surgical intervention, progression in the primary site during IST was identified in 13/42 patients (31%), of whom four patients also had progression in the distant disease. The 5-year survival was higher in the nonprogressive primary (74%) than the progressive primary disease group (52%) which did not reach statistical significance (p = 0.08). Age, pathologic tumor size, clinical nodal status, number of positive lymph nodes, and distant disease response to systemic therapy were significantly associated with survival. In this single institution experience, select patients with stage IV breast cancer at initial diagnosis who underwent resection of the primary tumor following systemic therapy achieved favorable overall and distant progression-free survival. Surgery is reasonable to consider for local palliation or in selected patients who have excellent response to systemic therapy and good performance status.

Surgical Management of Axilla Following Neoadjuvant Endocrine Therapy

BACKGROUND

Randomized clinical trials support deescalation of axillary surgery in breast cancer patients with low-volume axillary disease treated with a surgery-first approach. However, few data exist to guide axillary surgery following neoadjuvant endocrine therapy (NET). Therefore, we evaluated the extent and outcomes of axillary surgery in a contemporary cohort of NET patients, a treatment approach that has become particularly relevant during the coronavirus disease-19 (COVID-19) pandemic.

PATIENTS AND METHODS

We identified invasive breast cancer patients treated with NET between October 2008 and November 2019. Patients presenting with stage IV disease or recurrent disease were excluded. Statistical analyses were performed using chi-square, Fisher's exact, and Wilcoxon rank-sum tests.

RESULTS

194 invasive breast cancers in 186 patients (median age 66 years) were evaluated; 81 patients had breast-conserving surgery (BCS), while 113 underwent mastectomy. Eighty-four patients (43.3%) were biopsy-proven cN+ with 4/84 (4.8%) ypN0 following NET. Among cN+ patients, 14 (16.7%) had sentinel lymph node biopsy (SLNB) only, 27 (32.1%) had SLNB + axillary lymph node dissection (ALND), and 43 (51.2%) had ALND. Among 110 cN0 patients, 99 had axillary surgery with 28/99 (28.3%) ypN+: SLNB in 83 (75.5%), SLNB+ALND in 14 (12.7%), and ALND in 2 (1.8%). Among all ypN+ patients, 23/108 (21.3%) had SLNB alone: 18/43 (41.9%) of BCS and 5/65 (7.7%) mastectomy patients (p < 0.001). After median follow-up of 35 months, no regional recurrences were observed.

CONCLUSIONS

Among biopsy-proven cN+ NET patients, we observed deescalation of axillary surgery in selected patients, despite a low nodal pathologic complete response (pCR) rate, without nodal recurrences. These data suggest that patients with low-volume axillary disease treated with NET may be managed similarly to patients treated with a surgery-first approach.

Somatic mutations in benign breast disease tissues and association with breast cancer risk

Background

Benign breast disease (BBD) is a risk factor for breast cancer (BC); however, little is known about the genetic alterations present at the time of BBD diagnosis and how these relate to risk of incident BC.

Methods

A subset of a long-term BBD cohort was selected to examine DNA variation across three BBD groups (42 future estrogen receptor-positive (ER+) BC, 36 future estrogen receptor-negative (ER−) BC, and 42 controls cancer-free for at least 16 years post-BBD). DNA extracted from archival formalin fixed, paraffin-embedded (FFPE) tissue blocks was analyzed for presence of DNA alterations using a targeted panel of 93 BC-associated genes. To address artifacts frequently observed in FFPE tissues (e.g., C>T changes), we applied three filtering strategies based on alternative allele frequencies and nucleotide substitution context. Gene-level associations were performed using two types of burden tests and adjusted for clinical and technical covariates.

Results

After filtering, the variant frequency of SNPs in our sample was highly consistent with population allele frequencies reported in 1 KG/ExAC (0.986, p < 1e−16). The top ten genes found to be nominally associated with later cancer status by four of 12 association methods(p < 0.05) were MED12, MSH2, BRIP1, PMS1, GATA3, MUC16, FAM175A, EXT2, MLH1 and TGFB1, although these were not statistically significant in permutation testing. However, all 10 gene-level associations had OR < 1 with lower mutation burden in controls compared to cases, which was marginally statistically significant in permutation testing (p = 0.04). Comparing between the three case groups, BBD ER+ cases were closer to controls in mutation profile, while BBD ER− cases were distinct. Notably, the variant burden was significantly higher in controls than in either ER+ or ER− cases. CD45 expression was associated with mutational burden (p < 0.001).

Conclusions

Somatic mutations were more frequent in benign breast tissue from women who did not develop cancer, opening questions of clonal diversity or immune-mediated restraint on future cancer development. CD45 expression was positively associated with mutational burden, most strongly in controls. Further studies in both normal and premalignant tissues are needed to better understand the role of somatic gene mutations and their contribution to future cancer development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01032-8.

Abstract 2274: Somatic variant burdenin benign breast disease and association with risk of subsequent breast cancer

Benign breast disease (BBD) is an established risk factor for development of breast cancer (BC). However, little is known about the prevalence of somatic genetic alterations at the time of BBD diagnosis and relationship to subsequent BC. To characterize DNA variants in BBD and investigate association with BC risk, we isolated DNA from formalin-fixed paraffin-embedded (FFPE) BBD biopsies and assessed mutations using a panel of 93 breast cancer predisposition genes (Qiagen GeneRead). The study set consisted of 120 BBD patients from three age-matched groups defined based on 16 years of BC follow-up: BBD-controls (cancer-free after 16 years), BBD-ER+, or BBD-ER- breast cancer (within 16 years). Bioinformatics quality checks included comparisons of paired fresh-frozen and FFPE replicates to reduce false variant calls induced by FFPE artifacts. Gene-level variant burden differences among study groups were assessed using 12 statistical approaches, adjusted for patient age, year of biopsy, and histology. To investigate possible immune implications of increased variant burden, extent of leukocytes in the BBD biopsies was assessed using CD45 immunohistochemistry. To assess variant profile changes during the progression from BBD to BC, we also performed targeted sequencing of 12 BBD-matched subsequent tumor samples (six ER+ and six ER-) developed within 5 years of BBD diagnosis. Gene-level association results showed consistently skewed distributions suggesting a higher variant burden in BBD controls: among the top 10 genes associated with case-status (p&lt;0.05), all had BC-risk odds ratio estimates less than 1.0. Immune infiltrates, assessed by CD45 H-scores, were positively associated with overall variant burden (r=0.42, p=0.0031), and noticeably higher in cancer-free controls (r=0.50, p=0.005). Comparison of mutation variants in 12 BBD cases that developed cancer within 5 years of diagnosis and their subsequent tumors revealed that more than half of the non-SNP variants were shared between the BBD and the subsequent tumor (54.6%), whereas less than one quarter were unique to the tumor (20.6%) or unique to the BBD (24.9%). Through BBD-BC paired variant analysis, three subjects were found with newly emergent clones uniquely appearing in the tumors and four subjects had loss of clones in the tumor that were present in the BBD. These results show that somatic variant burden is lower in patients with BBD that progress to BC, mutation profiles of BC progression are heterogeneous, and BBD tissues with reduced variant burden also show reduced immune infiltrate. This implicates a potential protective role for immune activation in BBD. Future directions will define the characteristics of the potentially protective immune response and its role in variant heterogeneity in a larger sample set, integrated with paired RNA sequencing to better understand the pathways involved and the relationship to immune infiltration.

Citation Format: Stacey J. Winham, Julie M. Cunningham, Yuanhang Liu, Aditya V. Bhagwate, Ethan P. Heinzen, Samantha J. McDonough, Melody L. Stallings-Mann, Robert A. Vierkant, Jodi M. Carter, Mark E. Sherman, Derek C. Radisky, Amy C. Degnim, Chen Wang. Somatic variant burdenin benign breast disease and association with risk of subsequent breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2274.

Aurora-A kinase oncogenic signaling mediates TGF-β-induced triple-negative breast cancer plasticity and chemoresistance

Triple-negative breast cancer (TNBCs) account for 15–20% of all breast cancers and represent the most aggressive subtype of this malignancy. Early tumor relapse and progression are linked to the enrichment of a sub-fraction of cancer cells, termed breast tumor-initiating cells (BTICs), that undergo epithelial to mesenchymal transition (EMT) and typically exhibit a basal-like CD44^high/CD24^low and/or ALDH1^high phenotype with critical cancer stem-like features such as high self-renewal capacity and intrinsic (de novo) resistance to standard of care chemotherapy. One of the major mechanisms responsible for the intrinsic drug resistance of BTICs is their high ALDH1 activity leading to inhibition of chemotherapy-induced apoptosis. In this study, we demonstrated that aurora-A kinase (AURKA) is required to mediate TGF-β-induced expression of the SNAI1 gene, enrichment of ALDH1^high BTICs, self-renewal capacity, and chemoresistance in TNBC experimental models. Significantly, the combination of docetaxel (DTX) with dual TGF-β and AURKA pharmacologic targeting impaired tumor relapse and the emergence of distant metastasis. We also showed in unique chemoresistant TNBC cells isolated from patient-derived TNBC brain metastasis that dual TGF-β and AURKA pharmacologic targeting reversed cancer plasticity and enhanced the sensitivity of TNBC cells to DTX-based-chemotherapy. Taken together, these findings reveal for the first time the critical role of AURKA oncogenic signaling in mediating TGF-β-induced TNBC plasticity, chemoresistance, and tumor progression.

Abstract PD10-10: Epithelial proliferation score as an independent breast cancer risk predictor in benign breast disease

Background: Women with benign breast disease (BBD) experience an increased risk of breast cancer (BC). Histologic classification of BBD, as non-proliferative disease (NP), proliferative disease without atypia (PDWA) or atypical hyperplasia (AH), stratifies groups of patients into progressively higher categories of BC risk. However, this classification does not comprehensively assess the proliferative state of the epithelium throughout the biopsy. In addition, while AH is considered the most high-risk class of BBD, it is not always a highly proliferative lesion; atypical ductal lesions may reflect focal cytologic and architectural changes. We evaluated the association of an alternative classification of BBD severity and BC risk based on subjective grading of: 1) the maximal degree of epithelial proliferation and 2) multifocality of epithelial proliferation. Methods: Pathologists reviewed biopsies from participants aged 18 to 85 years in the Mayo BBD cohort (2002-2013), masked to BC outcomes, ascertained via questionnaires, tumor registry data and medical record review. Biopsies were classified as NP, PDWA or AH and semi-quantitatively scored for: 1) maximal degree of epithelial proliferation within a focus (DP) (0-3; none to severe) and 2) multifocality of proliferation (MP) (0-3; none to multiple foci). DP and MP scores were also summed to give a DP+MP score (0-6). Associations of DP and MP with BC risk were examined using Cox proportional hazards regression analyses, adjusting for age at BBD biopsy. Women were followed from date of initial biopsy to date of BC, death or last follow-up. Results: Of the 1529 assessable biopsies, 544 (35.6%) were classified as NP, 708 (46.3%) as PDWA and 277 (18.1%) as AH. Both DP and MP scores had significant positive correlation with increasing BBD severity (DP: r=0.51, p&lt; 0.001; MP: r=0.52, p&lt; 0.001). Mean (SD) DP scores were 0.6 (0.6) for NP, 1.6 (0.9) for PDWA, and 1.8 (0.7) for AH (ANOVA p&lt;0.001). Mean (SD) for MP scores were 0.6 (0.6) for NP, 1.4 (0.8) for PDWA, and 1.8 (0.8) for AH (ANOVA p&lt;0.001). Mean (SD) for DP+MP scores were 1.2 (1.2) for NP, 2.9 (1.5) for PDWA, and 3.6 (1.2) for AH (ANOVA p&lt;0.001). With median follow-up of 8.8 years for controls and 5.3 years for cases, 10.6% of the women in the cohort developed BC. Compared to those with DP scores of 0, women with DP scores of 3 had significantly increased BC risk (HR 1.42, 95% CI: 1.16, 1.74, p=0.003). MP was associated with a non-significant increase in BC risk for scores of 3 versus 0 (HR: 1.20, 95% CI: 0.97,1.49, p=0.11). DP+MP scores of 6 conferred the highest BC risk (HR (score 6 vs. 0): 1.62, 95% CI 1.18,2.21, p=0.02). Results did not substantively differ after adjusting for BBD severity as NP, PDWA or AH. Conclusions: In this preliminary analysis within the Mayo BBD cohort, both proliferative degree (DP) and multifocality (MP) scores were correlated with histologic severity of BBD. DP and DP+MP scores were each associated with increased BC risk. We conclude that improved characterization of epithelial proliferation in BBD biopsies may enable refined prediction of individual BC risk.

Citation Format: Jodi M Carter, Matthew R Jensen, Robert A Vierkant, Stacey J Winham, Tanya L Hoskin, Marlene Frost, Karthik Ghosh, Derek C Radisky, Amy C Degnim, Mark E Sherman. Epithelial proliferation score as an independent breast cancer risk predictor in benign breast disease [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD10-10.

Using operative features to identify surgical complexity: a case in breast surgery practice

Increasing workload is one of the main problems that surgical practices face. This increase is not only due to the increasing demand volume but also due to increasing case complexity. This raises the question on how to measure and predict the complexity to address this issue. Predicting surgical duration is critical to parametrize surgical complexity, improve surgeon satisfaction by avoiding unexpected overtime, and improve operation room utilization. Our objective is to utilize the historical data on surgical operations to obtain complexity groups and use this groups to improve practice.Our study first leverages expert opinion on the surgical complexity to identify surgical groups. Then, we use a tree-based method on a large retrospective dataset to identify similar complexity groups by utilizing the surgical features and using surgical duration as a response variable. After obtaining the surgical groups by using two methods, we statistically compare expert-based grouping with the data-based grouping. This comparison shows that a tree-based method can provide complexity groups similar to the ones generated by an expert by using features that are available at the time of surgical listing. These results suggest that one can take advantage of available data to provide surgical duration predictions that are data-driven, evidence-based, and practically relevant.

Impact of Personalized Genetic Breast Cancer Risk Estimation With Polygenic Risk Scores on Preventive Endocrine Therapy Intention and Uptake

Endocrine therapy is underutilized to reduce breast cancer incidence among women at increased risk. Polygenic risk scores (PRSs) assessing 77 breast cancer genetic susceptibility loci personalizes risk estimates. We examined effect of personalized PRS breast cancer risk prediction on intention to take and endocrine therapy uptake among women at increased risk. Eligible participants had a 10-year breast cancer risk ≥5% by Tyrer-Cuzick model [International Breast Cancer Intervention Study (IBIS)] or ≥3.0 % 5-year Gail Model risk with no breast cancer history or hereditary breast cancer syndrome. Breast cancer risk was estimated, endocrine therapy options were discussed, and endocrine therapy intent was assessed at baseline. After genotyping, PRS-updated breast cancer risk estimates, endocrine therapy options, and intent to take endocrine therapy were reassessed; endocrine therapy uptake was assessed during follow-up. From March 2016 to October 2017, 151 patients were enrolled [median (range) age, 56.1 (36.0-76.4 years)]. Median 10-year and lifetime IBIS risks were 7.9% and 25.3%. Inclusion of PRS increased lifetime IBIS breast cancer risk estimates for 81 patients (53.6%) and reduced risk for 70 (46.4%). Of participants with increased breast cancer risk by PRS, 39 (41.9%) had greater intent to take endocrine therapy; of those with decreased breast cancer risk by PRS, 28 (46.7%) had less intent to take endocrine therapy (P < 0.001). On multivariable regression, increased breast cancer risk by PRS was associated with greater intent to take endocrine therapy (P < 0.001). Endocrine therapy uptake was greater among participants with increased breast cancer risk by PRS (53.4%) than with decreased risk (20.9%; P < 0.001). PRS testing influenced intent to take and endocrine therapy uptake. Assessing PRS effect on endocrine therapy adherence is needed.Prevention Relevance: Counseling women at increased breast cancer risk using polygenic risk score (PRS) risk estimates can significantly impact preventive endocrine therapy uptake. Further development of PRS testing to personalize breast cancer risk assessments and endocrine therapy counselling may serve to potentially reduce the incidence of breast cancer in the future.

Breast Reconstruction in the Setting of Stage 4 Breast Cancer: Is It Worthwhile?

BACKGROUND

The role of reconstruction after primary tumor surgery for metastatic breast cancer remains controversial. This report describes the outcomes for patients undergoing mastectomy with and without reconstruction in the setting of de novo stage 4 breast cancer.

METHODS

Using a prospectively maintained institutional breast surgery database, this study identified all patients who presented with de novo stage 4 breast cancer from January 2008 to December 2018. Patients were included if they had undergone mastectomy with or without reconstruction. Patient, surgical characteristics, and survival outcomes were abstracted and analyzed.

RESULTS

The study identified 29 patients: 8 patients (28%) who underwent reconstruction (R) and 21 patients (72%) who did not (NR). Complete clinical response to induction systemic therapy was more frequent among patients in the R group than among those in the NR group for the primary disease (50% in R, 5% in NR), and to a lesser degree for distant disease (63% in R, 39% in NR). No difference in complication rates between the two groups was identified [n = 1 (13%) in R; n = 2 (10%) in NR; p = 1.0]. Overall survival from surgery was longer in the R group (100% at 2 and 5 years) than in the NR group [85%; 95% confidence interval (CI), 68-100% at 2 years vs 50%; 95% CI 27-91% at 5 years] (p = 0.046).

CONCLUSION

Breast reconstruction after mastectomy may be reasonable to consider for appropriately selected patients with de novo stage 4 breast cancer who have excellent responses to systemic therapy and anticipated durable survival.

Upgrade at excisional biopsy after a core needle biopsy diagnosis of classic lobular carcinoma in situ

BACKGROUND

Management of patients with classic lobular carcinoma in situ diagnosed on core needle biopsy remains controversial, in part because of clinicopathologic overlap with atypical lobular hyperplasia. Although atypical lobular hyperplasia on core needle biopsy is observed because of its low upgrade rate (~1%), consensus is lacking for lobular carcinoma in situ. Therefore, we evaluated lobular carcinoma in situ upgrade rates.

METHODS

With institutional review board approval, we identified 90 patients (from October 2008 to December 2019) with lobular carcinoma in situ on core needle biopsy as their highest-risk lesion. We excluded patients with concurrent ipsilateral cancer. Variables associated with upgrade were assessed with logistic regression.

RESULTS

Of the 90 patients, 81 (90%), median age 55 y, underwent surgical excision. Indications for diagnostic core needle biopsy included mammographic calcifications (48, 53.3%), mass/distortion (28, 31.1%), and non-mass enhancement (12, 13.3%). Final surgical pathology upgraded 11 of 81 patients (13.6%, 95% CI: 7.8%-22.7%) to cancer: invasive lobular (n = 7), invasive ductal (n = 1), and ductal carcinoma in situ/pleomorphic lobular carcinoma in situ (n = 3). Only 1 patient with invasive cancer was node-positive. Concurrent contralateral cancer (OR 4.41, 95% CI: 1.06-17.38, P = .04) and larger lesion size (OR 1.78 per 1 cm, 95% CI: 1.19-2.95, P = .005) predicted upgrade.

CONCLUSION

Our data suggest that, unlike atypical lobular hyperplasia, lobular carcinoma in situ identified on core needle biopsy should be surgically excised. The high proportion of upgrades to early stage invasive lobular carcinoma underscores the value of this approach.

Abstract 4635: Analysis of post-partum breast tissue to understand early onset breast cancer

Background: Parity reduces risk of late onset breast cancer (BC), but childbirth is associated with a transient rise in BC risk. In a prior analysis of normal breast tissues donated for research to the Komen Tissue Bank (KTB), we reported that numbers of lobules (the primary structures from which BCs arise) are increased among parous versus nulliparous women. To further define the histological features that may be related to the transient rise in post-partum BC risk, we performed an expanded histologic review of 757 breast tissues donated to the KTB by women ≤45 years of age and compared lobule number, acinar count per lobule, and abundance of immune cells, and specifically plasma cells, between nulliparous and parous women.

Methods: We assessed digital scans of H&E stained tissue sections of KTB tissues for total number of lobules, and evaluated acini / lobule (ordinal categories) and lobule span (um) for ≤10 lobules per section. Masked to epidemiologic data, we subjectively assessed images including ≥5 lobules for the presence of benign breast disease (BBD), ≥3 plasma cells per section and increased immune cells in lobules. We compared parous women according to time since last birth (≤5 years or &gt;5 years) to nulliparas (referent) using age-adjusted regression models appropriate for data type (count, continuous, ordinal, or categorical).

Results: Compared to nulliparous women, parous women ≤5 years of a birth had a 1.83-fold increase in lobule counts (95% confidence interval [CI]: 1.47-2.28, P&lt;0.001), increased plasma cells in lobules (OR=1.86; 95% CI: 1.08-3.18, P&lt;0.025), and subjectively, increased immune cells in lobules (OR=2.46, 95% CI: 1.39-4.36, P&lt;0.002). Comparisons of parous women ≥5 years post-partum to nulliparas revealed a 1.83-fold increase in numbers of lobules (95% CI: 1.42-2.36, P&lt;0.001); however, lobule span in parous women was 0.89 times that of nulliparous women (95% CI: 0.80-0.99, P=0.037) and other features assessed did not show statistically significant differences.

Conclusion: Histologically, normal breast tissues reveal persistently increased lobule counts and increased plasma cells and inflammation for ≤5 years post-partum compared with nulliparous women, although other lobular features decrease between ≤5 and &gt;5 years after a birth. Future molecular studies will define how these changes in the epithelium and microenvironment during the post-partum period may inform mechanisms that mediate the transient increase in BC risk after childbirth and the reduction in BC risk that occurs later in life.

Citation Format: Joshua Ogony, DereK C. Radisky, Amy C. Degnim, Marlene Frost, Tanya L. Hoskin, Michael G. Heckman, Launia J. White, Mark E. Sherman. Analysis of post-partum breast tissue to understand early onset breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4635.

Abstract 2113: Discrimination of benign breast disease from normal lobules using an automated computational pathology algorithm

Background: Biopsy diagnosis of benign breast disease (BBD) based on the most severe lesion in a sample predicts future breast cancer risk and has implications for screening and management. Lobules are the functional unit of the breast and the structures from which BBD arises. We developed and preliminarily validated an automated computational pathology algorithm to discriminate normal from BBD breast lobules as a step toward automated comprehensive characterization of benign biopsies.

Methods: 152 BBD biopsies (27 training, 125 validation) from the Mayo Clinic were examined using scanned digital images of H&E stained sections. For each image, a pathologist annotated up to 10 representative lobules as normal or BBD using standard pathology criteria. A deep learning algorithm to quantify lobular features was developed using 129 lobules from 27 subjects. Nine features were identified that discriminate normal vs BBD lobules, expressing lobule size, acini size and number, acinar lumen size, proportion of lobular stroma, and capillaries. Here, we validate their performance to discriminate normal vs BBD lobules in a set of 1250 lobules from 125 subjects using area under the ROC curve (AUC) analysis. Random forest analysis was used for multivariable modeling; model performance was assessed with a tenfold cross-validation approach.

Results: Median subject age was 52 years. Among the 125 validation subjects, BBD findings were nonproliferative in 39%, proliferative in 45%, and atypical hyperplasia in 16%. Sections included 552 (44%) normal lobules and 698 BBD (56%) lobules, with representation of both lobule types on each section. In univariate analyses, four individual features showed good discrimination between normal vs. BBD lobules, yielding the following AUCs: lobule size= 0.74, mean acini size= 0.75, epithelial area= 0.75, and number of acini with large lumens= 0.76. Lobule size and epithelial area were highly correlated (Spearman rank correlation r = 0.95), but both of these features showed lower correlation with mean acini size and number of acini with large lumens (each r &lt; 0.5). With random forest modeling, number of acini with large lumens was the strongest discriminating feature, followed by mean acini size, lobule size, and epithelial area. With ten-fold cross validation of the multivariable random forest model, the overall AUC was 0.82 (95% CI: 0.79-0.85).

Conclusion: Our validation showed that automated quantitative computational pathology assessment of breast lobules can discriminate normal versus BBD on a per lobule basis. This finding supports the feasibility of developing automated algorithms to classify every lesion in breast biopsies, expanding beyond visual assessment. Further studies using deep learning may reveal novel pathology features for classifying BBD biopsies with the potential to strengthen estimation of breast cancer risk.

Citation Format: Amy C. Degnim, Thomas de Bel, Mark E. Sherman, Derek C. Radisky, Stacey J. Winham, Tanya L. Hoskin, Melody L. Stallings Mann, Marlene Frost, Robert A. Vierkant, Brendan T. Broderick, Ethan P. Heinzen, Rushin Brahmbhatt, Muhammad Arshad, Celine M. Vachon, Jodi M. Carter, Lori A. Denison, Daniel W. Visscher, Jeroen van der Laak. Discrimination of benign breast disease from normal lobules using an automated computational pathology algorithm [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2113.

Breast Cancer Risk and Use of Nonsteroidal Anti-inflammatory Agents After a Benign Breast Biopsy

Over one million women in the United States receive biopsy diagnoses of benign breast disease (BBD) each year, which confer a 1.5-4.0-fold increase in breast cancer risk. Studies in the general population suggest that nonsteroidal anti-inflammatory agents (NSAID) lower breast cancer risk; however, associations among women with BBD are unknown. We assessed whether NSAID use among women diagnosed with BBD is associated with lower breast cancer risk. Participants included 3,080 women (mean age = 50.3 ± 13.5 years) in the Mayo BBD surgical biopsy cohort diagnosed between January 1, 1992 and December 31, 2001 who completed breast cancer risk factor questionnaires that assessed NSAID use, and whose biopsies underwent detailed pathology review, masked to outcome. Women were followed from date of BBD biopsy to breast cancer diagnosis (main outcome) or censoring (death, prophylactic mastectomy, reduction mammoplasty, lobular carcinoma in situ or last contact). Median follow-up time was 16.4 ± 6.0 years. Incident breast cancer was diagnosed among 312 women over a median follow-up of 9.9 years. Regular non-aspirin NSAID use was associated with lower breast cancer risk [HR = 0.63; 95% confidence interval (CI) = 0.46-0.85; P = 0.002] with trends of lower risk (highest tertiles of use vs. nonuse) for greater number of years used [HR = 0.55; 95% CI = 0.31-0.97; P _trend = 0.003), days used per month (HR = 0.51; 95% CI = 0.33-0.80; P _trend = 0.001) and lifetime number of doses taken (HR = 0.53; 95% CI = 0.31-0.89; P _trend = 0.003). We conclude that nonaspirin NSAID use is associated with statistically significant lower breast cancer risk after a BBD biopsy, including a dose-response effect, suggesting a potential role for NSAIDs in breast cancer prevention among patients with BBD.

Intraoperative Pathologic Margin Analysis and Re-Excision to Minimize Reoperation for Patients Undergoing Breast-Conserving Surgery

BACKGROUND

Reoperation rates following breast-conserving surgery (BCS) range from 10 to 40%, with marked surgeon and institutional variation.

OBJECTIVE

The aim of this study was to identify factors associated with intraoperative margin re-excision, evaluate for any differences in local recurrence based on margin re-excision and determine reoperation rates with use of intraoperative margin analysis.

PATIENTS AND METHODS

We analyzed consecutive patients with ductal carcinoma in situ (DCIS) or invasive breast cancer who underwent BCS at our institution between 1 January 2005 and 31 December 2016. Routine intraoperative frozen section margin analysis was performed and positive or close margins were re-excised intraoperatively. Univariate analysis was used to compare margin status and the Kaplan-Meier method was used to compare recurrence. Multivariable logistic regression was utilized to analyze factors associated with re-excision.

RESULTS

We identified 3201 patients who underwent BCS-688 for DCIS and 2513 for invasive carcinoma. Overall, 1513 (60.2%) patients with invasive cancer and 434 (63.1%) patients with DCIS had close or positive margins that underwent intraoperative re-excision. Margin re-excision was associated with larger tumor size in both groups. The permanent pathology positive margin rate among all patients was 1.2%, and the 30-day reoperation rate for positive margins was 1.1%. Five-year local recurrence rates were 0.6% and 1.2% for patients with DCIS and invasive cancer, respectively. There was no difference in recurrence between patients with and without intraoperative margin re-excision (p = 0.92).

CONCLUSION

Both DCIS and invasive carcinoma had similar rates of intraoperative margin re-excision. Although intraoperative margin re-excision was common, the reoperation rate was extremely low and there was no difference in recurrence between those with or without intraoperative re-excision.

Bioimpedance Spectroscopy of the Breast

Background: Bioimpedance spectroscopy (BIS) measurements of breast lymphedema poses practical and technical challenges, in particular the determination of the resistance at zero frequency (R₀), the index of change in breast lymph content. Conventionally, R₀ is calculated from data analysis by using a procedure eponymously known as Cole modeling, a method that is error-prone in the breast. The aim of this study was to evaluate polynomial curve fitting as an alternative analytic procedure. Methods and Results: A sub-set of breast BIS measurements from 41 women with self-ascribed breast lymphedema obtained as part of the Breast Edema Exercise Trial (BEET) were analyzed by both the Cole and polynomial methods. BIS files for all subjects were able to be analyzed by using the polynomial method but only 73% and 88% of data files were analyzed for the affected and unaffected breasts, respectively, by using the Cole method. For those files that were capable of being analyzed by both methods, R₀ values were highly correlated (r = 0.99) but with a small (1.6%) although statistically significant difference (paired t test, p < 0.001) between methods. Conclusions: Analysis of BIS data using polynomial curve fitting is an acceptable and robust alternative to Cole modeling, particularly where impedance measurements are susceptible to technical sources of error of measurement. The small magnitude of difference observed between methods is unlikely to lead to misclassification of patients with lymphedema based on BIS assessment.

Cytotoxic T cell depletion with increasing epithelial abnormality in women with benign breast disease

Purpose

We quantified cytotoxic T cells in nonmalignant breast tissues from women with and without subsequent breast cancer to assess evidence of whether immunosurveillance may be suppressed prior to tumor development.

Methods

We used an age-matched set of breast tissues from women with benign breast disease (BBD) who subsequently developed breast cancer (BBD with later BC), women with BBD who remained cancer free (BBD cancer-free), and normal Komen Tissue Bank (KTB) tissue donors (KTB controls). We evaluated terminal duct lobular units (lobules) for degree of epithelial abnormality and density of dual-positive CD8/CD103 T cells, as CD103+ cells are thought to be a subset of CD8+ cytotoxic T cells located primarily in the intraepithelial compartment.

Results

In 10 sets of age-matched women, 256 breast lobules were studied: 85 in BBD women with later BC, 85 in BBD cancer-free women, and 86 in KTB donors. The majority of all lobules were histologically normal (N = 143, 56%), with 65 (25%) nonproliferative fibrocystic change, and 48 (19%) proliferative epithelial change (with or without atypia). In BBD women with later BC, median CD8+/CD103+ cell density was 39.6, 31.7, and 10.5 cells/mm² (p = 0.002) for normal, nonproliferative, and proliferative lobules. In BBD cancer-free women, median CD8+/CD103+ cell density values were 46.7, 14.3, and 0 cells/mm² (p = 0.004) respectively. In KTB donors, CD8+/CD103+ cell density was not significantly different across the lobule types (medians 0, 5.8, 10.7, p = 0.43).

Conclusion

In women with BBD, breast lobules with increasing epithelial abnormality show significant decreases in cytotoxic T cells as measured by CD8/CD103 staining, suggesting that impaired immunosurveillance may be a component of the earliest stages of breast cancer development.

Workload Differentiates Breast Surgical Procedures: NSM Associated with Higher Workload Demand than SSM

Background

Breast surgery has evolved with more focus on improving cosmetic outcomes, which requires increased operative time and technical complexity. Implications of these technical advances in surgery for the surgeon are unclear, but they may increase intraoperative demands, both mentally and physically. We prospectively evaluated mental and physical demand across breast surgery procedures, and compared surgeon ergonomic risk between nipple-sparing (NSM) and skin-sparing mastectomy (SSM) using subjective and objective measures.

Methods

From May 2017 to July 2017, breast surgeons completed modified NASA-Task Load Index (TLX) workload surveys after cases. From January 2018 to July 2018, surgeons completed workload surveys and wore inertial measurement units to evaluate their postures during NSM and SSM cases. Mean angles of surgical postures, ergonomic risk, survey items, and patient factors were analyzed.

Results

Procedural duration was moderately related to surgeon frustration, mental and physical demand, and fatigue (p < 0.001). NSMs were rated 23% more physically demanding (M = 13.3, SD = 4.3) and demanded 28% more effort (M = 14.4, SD = 4.6) than SSMs (M = 10.8, SD = 4.7; M = 11.8, SD = 5.0). Incision type was a contributing factor in workload and procedural difficulty. Left arm mean angle was significantly greater for NSM (M = 30.1 degrees, SD = 6.6) than SSMs (M = 18.2 degrees, SD = 4.3). A higher musculoskeletal disorder risk score for the trunk was significantly associated with higher surgeon physical workload (p = 0.02).

Conclusion

Nipple-sparing mastectomy required the highest surgeon-reported workload of all breast procedures, including physical demand and effort. Objective measures identified the surgeons’ left upper arm as being at the greatest risk for a work-related musculoskeletal disorder, specifically from performing NSMs.

Rapid Generation of Sustainable HER2-specific T-cell Immunity in Patients with HER2 Breast Cancer using a Degenerate HLA Class II Epitope Vaccine

PURPOSE

Patients with HER2⁺ breast cancer benefit from trastuzumab-containing regimens with improved survival. Adaptive immunity, including cytotoxic T-cell and antibody immunity, is critical to clinical efficacy of trastuzumab. Because Th cells are central to the activation of these antitumor effectors, we reason that HER2 patients treated with trastuzumab may benefit by administering vaccines that are designed to stimulate Th-cell immunity.

PATIENTS AND METHODS

We developed a degenerate HER2 epitope-based vaccine consisting of four HLA class II-restricted epitopes mixed with GM-CSF that should immunize most (≥84%) patients. The vaccine was tested in a phase I trial. Eligible women had resectable HER2⁺ breast cancer and had completed standard treatment prior to enrollment and were disease free. Patients were vaccinated monthly for six doses and monitored for safety and immunogenicity.

RESULTS

Twenty-two subjects were enrolled and 20 completed all six vaccines. The vaccine was well tolerated. All patients were alive at analysis with a median follow-up of 2.3 years and only two experienced disease recurrence. The percent of patients that responded with augmented T-cell immunity was high for each peptide ranging from 68% to 88%, which led to 90% of the patients generating T cells that recognized naturally processed HER2 antigen. The vaccine also augmented HER2-specific antibody. Immunity was sustained in patients with little sign of diminishing at 2 years following the vaccination.

CONCLUSIONS

Degenerate HLA-DR-based HER2 vaccines induce sustainable HER2-specific T cells and antibodies. Future studies, could evaluate whether vaccination during adjuvant treatment with trastuzumab-containing regimens improves patient outcomes.

Oncologic Safety of Prophylactic Nipple-Sparing Mastectomy in a Population With BRCA Mutations: A Multi-institutional Study

Importance

Nipple-sparing mastectomy (NSM) offers superior cosmetic outcomes and has been gaining wide acceptance; however, its role among patients with BRCA mutations remains controversial.

Objective

To report on the oncologic safety of NSM and provide evidence-based data to patients and health care professionals regarding preservation of the nipple-areolar complex during a risk-reducing mastectomy in a population with BRCA mutations.

Design, Setting, and Participants

We retrospectively reviewed the outcomes of 9 institutions' experience with prophylactic NSM from 1968 to 2013 in a cohort of patients with BRCA mutations. Patients with breast cancer were included if they underwent contralateral risk-reducing mastectomy; however, only the prophylactic side was considered in the analysis. Patients found to have an occult primary breast cancer at the time of risk-reducing mastectomy, those having variant(s) of unknown significance, and those undergoing free nipple grafts were excluded.

Main Outcomes and Measures

The primary outcome measure was development of a new breast cancer after risk-reducing NSM. Three reference data sources were used to model the expected number of events, and this was compared with our observed number of events.

Results

A total of 548 risk-reducing NSMs in 346 patients were performed at 9 institutions. The median age at NSM was 41 years (interquartile range, 34.5-47.5 years). Bilateral prophylactic NSMs were performed in 202 patients (58.4%), and 144 patients (41.6%) underwent a unilateral risk-reducing NSM secondary to cancer in the contralateral breast. Overall, 201 patients with BRCA1 mutations and 145 with BRCA2 mutations were included. With median and mean follow-up of 34 and 56 months, respectively, no ipsilateral breast cancers occurred after prophylactic NSM. Breast cancer did not develop in any patients undergoing bilateral risk-reducing NSMs. Using risk models for BRCA1/2 mutation carriers, approximately 22 new primary breast cancers were expected without prophylactic NSM. Prophylactic NSM resulted in a significant reduction in breast cancer events (test of observed vs expected events, P < .001).

Conclusions and Relevance

Nipple-sparing mastectomies are highly preventive against breast cancer in a BRCA population. Although the follow-up remains relatively short, NSM should be offered as a breast cancer risk-reducing strategy to appropriate patients with BRCA mutations.

Bioinformatics and DNA-extraction strategies to reliably detect genetic variants from FFPE breast tissue samples

Background

Archived formalin fixed paraffin embedded (FFPE) samples are valuable clinical resources to examine clinically relevant morphology features and also to study genetic changes. However, DNA quality and quantity of FFPE samples are often sub-optimal, and resulting NGS-based genetics variant detections are prone to false positives. Evaluations of wet-lab and bioinformatics approaches are needed to optimize variant detection from FFPE samples.

Results

As a pilot study, we designed within-subject triplicate samples of DNA derived from paired FFPE and fresh frozen breast tissues to highlight FFPE-specific artifacts. For FFPE samples, we tested two FFPE DNA extraction methods to determine impact of wet-lab procedures on variant calling: QIAGEN QIAamp DNA Mini Kit (“QA”), and QIAGEN GeneRead DNA FFPE Kit (“QGR”). We also used negative-control (NA12891) and positive control samples (Horizon Discovery Reference Standard FFPE). All DNA sample libraries were prepared for NGS according to the QIAseq Human Breast Cancer Targeted DNA Panel protocol and sequenced on the HiSeq 4000. Variant calling and filtering were performed using QIAGEN Gene Globe Data Portal. Detailed variant concordance comparisons and mutational signature analysis were performed to investigate effects of FFPE samples compared to paired fresh frozen samples, along with different DNA extraction methods.

In this study, we found that five times or more variants were called with FFPE samples, compared to their paired fresh-frozen tissue samples even after applying molecular barcoding error-correction and default bioinformatics filtering recommended by the vendor. We also found that QGR as an optimized FFPE-DNA extraction approach leads to much fewer discordant variants between paired fresh frozen and FFPE samples. Approximately 92% of the uniquely called FFPE variants were of low allelic frequency range (< 5%), and collectively shared a “C > T|G > A” mutational signature known to be representative of FFPE artifacts resulting from cytosine deamination. Based on control samples and FFPE-frozen replicates, we derived an effective filtering strategy with associated empirical false-discovery estimates.

Conclusions

Through this study, we demonstrated feasibility of calling and filtering genetic variants from FFPE tissue samples using a combined strategy with molecular barcodes, optimized DNA extraction, and bioinformatics methods incorporating genomics context such as mutational signature and variant allelic frequency.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-6056-8) contains supplementary material, which is available to authorized users.

Mastectomy and immediate breast reconstruction in the elderly: Trends and outcomes

BACKGROUND

Immediate breast reconstruction after mastectomy may confer more complication rates in the elderly. Therefore, granular analysis of postmastectomy complications in women aged ≥65 years may help formulate clinical guidelines to improve patient selection and outcomes.

METHODS

We identified patients undergoing mastectomy with or without immediate reconstruction from our breast surgery database (2014-2018). Complications requiring treatment were compared between patients aged ≥65 and <65 years.

RESULTS

A total of 1,721 mastectomies were performed in 1,698 patients; 85.8% had a 30-day follow-up. Of these patients, 968 (65.6%) had immediate breast reconstruction, of whom 95 (9.8%) were aged ≥65 years. Among patients aged ≥65 years, 27.6% underwent mastectomy with immediate breast reconstruction compared with 77.1% of women aged <65 years (P < .001). Overall complication rates were not greater for older compared with younger mastectomy patients but were for older versus younger patients who had mastectomy with immediate breast reconstruction (12.6% vs 6.8%; P = .04). Hematoma requiring reoperation was more frequent in patients aged ≥65 years (5.3% vs 0.9%; P = .006). Necrosis (5.3% vs 2.6%; P = .18) and 30-day unplanned readmissions (7.4% vs 4.0%; P = .18) were not greater.

CONCLUSION

Despite low overall postoperative complication rates, we found some clinically relevant differences between older and younger patients after mastectomy with immediate breast reconstruction. Additional investigation of contributing factors may help further refine patient selection. In the interim, elderly patients should be counseled on their somewhat greater risk of postoperative complications to facilitate shared decision making.

Impact of a breast cancer (BC) polygenic risk score (PRS) on the decision to take preventive endocrine therapy (ET): The Genetic Risk Estimate (GENRE) trial

1501

Background: Despite BC risk reduction of 50-65% by preventive endocrine therapy (ET), very few at-risk women choose to take them. A woman’s perceived BC risk correlates with uptake of ET. A PRS comprised of 77 BC genetic susceptibility loci (Single Nucleotide Polymorphisms (SNP) improves the accuracy of risk prediction for BC. We examined the impact of the addition of individualized PRS BC risk prediction to standard risk calculator estimates on intent to take BC prevention medication. Methods: Eligible women had ≥5% 10 yr BC Tyrer-Cuzick risk (IBIS) or 5 year Gail score ≥3%, with no history of BC or hereditary BC syndrome. Standard BC risk estimates (IBIS or Gail) were incorporated into the counselling on BC preventive ET. A self-reported questionnaire at baseline quantified intention to take ET and explored factors associated with this decision. Blood samples were obtained and genotyped for 77 SNPs, individualized PRS were calculated then incorporated into IBIS and Gail predictions for 5 yr, 10 yr, & lifetime BC risk. At a second visit, PRS risk & prevention recommendations were revisited. Post visit questionnaires assessed change in intent to take ET. Multivariable linear regression was performed to assess impact of baseline variables on change in intent to take medication. Results: From 2016 to 2017, 151 women in Canada & USA were enrolled, median age: 56.1 (range 36-76.4), 35.6% were premenopausal, 98.7% were Caucasian. Median 5yr, 10yr, & lifetime IBIS risk estimates were 3.8% (2.0-11.5), 7.9% (5.0-23.1), and 25.3% (5.5 to 92.2). PRS increased BC risk estimates in 84 (55.6%) and reduced BC risk estimates in 67 (44%) women. After PRS risk counselling, intention to take ET significantly changed (p<0.001): 41.9% of those with increased PRS were more inclined, and 46.7% of women with decreased PRS were less inclined to take ET. On multivariable regression, increase in PRS (p<0.0001) and less concern about ET side effects (p<0.0001) were associated with greater intent to take ET. Conclusions: In high risk women, PRS significantly changed BC risk estimates & intent to take preventive ET. Further assessments of the impact of PRS scores on compliance with ET are warranted. Clinical trial information: NCT02517593.