Postmastectomy Radiation Therapy Planning After Immediate Implant-based Reconstruction Using the European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice Consensus Guidelines for Target Volume Delineation

AIMS

To evaluate how common radiation therapy techniques perform in the setting of the new European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) delineation recommendations for immediate breast reconstruction (IBR).

MATERIALS AND METHODS

Seven Danish radiation therapy centres and six international European centres participated in this project. Two breast cancer cases (one left-sided and one right-sided) with a retropectoral implant were chosen for radiation therapy planning using deep-inspiration breath-hold. Target volumes were delineated according to ESTRO-ACROP delineation recommendations. The centres were asked to plan the cases using any radiation therapy technique according to the Danish Breast Cancer Group plan objectives.

RESULTS

In total, 35 treatment plans were collected. Half of the submitted plans, for both the left-sided and the right-sided case, used the field-in-field (FiF) technique (nine for each), a quarter used volumetric arc radiation therapy (VMAT; five for right-sided, four for left-sided) and the remaining quarter was a mix of inverse intensity-modulated radiation therapy (IMRT), helicoidal therapy and hybrid (combined open fields and VMAT) techniques. Mean clinical target volume doses were in the range 99-102% of the prescribed dose. The median FiF mean heart dose (MHD) for right-sided radiation therapy was 1 Gy (range 0.8-3.7) and 5.2 Gy for left-sided radiation therapy (range 2.2-6.5). For right-sided radiation therapy, the median VMAT MHD was 3.42 Gy, for IMRT was 2.3 Gy and for helicoidal therapy was 5.1 Gy. For left-sided radiation therapy, the median VMAT MHD was 6.3 Gy, for IMRT was 7.8 Gy and for helicoidal therapy was 7.3 Gy.

CONCLUSIONS

Different radiation therapy techniques could be used to plan radiation therapy in the setting of IBR. FiF provided good coverage with acceptable organ at risk doses. The best dose distribution results as a trade-off between the objectives of target volume coverage and high-dose organ at risk inclusion. The radiation therapy technique affects the interplay between these objectives.

Associations between intrauterine exposure to polychlorinated biphenyls on neonatal ano-genital distance

Polychlorinated Biphenyls (PCBs) are widespread environmental contaminants. PCBs have endocrine disrupting properties which raises concerns regarding their effect on the developing fetus. This study aimed to examine the association between prenatal exposure to PCBs and anogenital distance (AGD) in newborns. Serum concentrations of PCB congeners -118, -138, -153 and -180 were measured in 175 pregnant women presenting to the delivery room. AGD was measured in their newborns. Regression models were used to estimate associations between maternal PCB exposure and infant anogenital measurements, controlling for possible confounding variables. Mean maternal serum concentrations were 2.95 ± 2.18 ng/g, 4.62 ± 3.54 ng/g, 7.67 ± 6.42 ng/g and 5.10 ± 3.91 ng/g for congeners -118, -138, -153 and -180, respectively. Higher maternal concentrations of PCBs were associated with reduced AGD measures in male infants. Higher maternal concentrations of PCB-138 and PCB-153 were associated with reduced ano-scrotal distances and higher maternal concentrations of all four PCB congeners were associated with reduced ano-penile distances. No significant associations were found between any PCB congener and any AGD measure in female newborns. This study demonstrates that intrauterine exposure to PCBs may be associated with reduced AGD in male newborns. More research is needed to reveal the implications for adult reproductive health.

Perinatal phthalates exposure decreases fine-motor functions in 11-year-old girls: Results from weighted Quantile sum regression

INTRODUCTION

Phthalates are a group of high production chemicals, generally used as plasticizers and odor enhancers. Phthalates cross the blood-placenta barrier and are associated with deficits in cognitive functions and behavior problems in offspring. We previously reported sex-specific associations with motor function when phthalates are considered singly. Because exposure to phthalates usually occurs as mixtures, here we assess these associations between a mixture of phthalates and motor function at age 11 years.

METHODS

Data come from the prospective cohort study of mothers and offspring who participated in the Columbia Center for Children's Environmental Health birth cohort (CCCEH). Seven phthalate metabolites were measured in maternal spot urine obtained during the third trimester and motor function was evaluated using the short form of the Bruininks-Oseretsky Test of Motor Proficiency, 2nd edition (BOT-2) at the age of 11 years. We used Weighted Quartile Sum (WQS) regression models to examine the effect of phthalate metabolites in males and females separately. The models were adjusted for child age in months, child BMI, maternal race (African-American vs. Dominican), prenatal alcohol consumption, maternal demoralization score, HOME score, and urine specific gravity. In a secondary analysis we used linear regression models to examine the association between the sum of molar concentrations of both DEHP and non-DEHP metabolites, and outcomes of gross and fine motor functions.

RESULTS

209 mother-child pairs were eligible for this analysis. A significant decrease in fine-motor functions was observed among females, but not among males, following exposure to high levels of weighted quartile sum of seven phthalate metabolites (Covariates-adjusted coefficient estimate B = -2.7, 95% Confidence Interval [CI] -4.64 to -0.75, p = 0.01 for females [n = 116] and B = -1.63, 95%CI -3.94 to 0.69, p = 0.16 for males [n = 93]). The most highly weighted phthalate metabolites, associated with fine-motor functions among females, were MBP, MBZP, and MIBP, all non-DEHP phthalates. No significant associations were found between the weighted quartile sum of seven phthalate metabolites and gross-motor functions at the age of 11 years for males (B = -0.81, 95%CI -1.17 to 1.96, p = 0.23). With the molar sum of four non-DEHP phthalates as main predictor of linear regression models, we found significant decrease in gross and fine motor functions among females prenatally exposed to non-DEHP phthalates B = -0.98, 95%CI -1.98 to 0.03, p = 0.05 and B = -0.85, 95%CI -1.49 to -0.20, p = 0.01, respectively).

CONCLUSIONS

Phthalate exposure during pregnancy was associated with decreased motor functions among 11-year-old girls.

Guidelines for the management of glucocorticoids during the peri-operative period for patients with adrenal insufficiency: Guidelines from the Association of Anaesthetists, the Royal College of Physicians and the Society for Endocrinology UK

These guidelines aim to ensure that patients with adrenal insufficiency are identified and adequately supplemented with glucocorticoids during the peri-operative period. There are two major categories of adrenal insufficiency. Primary adrenal insufficiency is due to diseases of the adrenal gland (failure of the hormone-producing gland), and secondary adrenal insufficiency is due to deficient adrenocorticotropin hormone secretion by the pituitary gland, or deficient corticotropin-releasing hormone secretion by the hypothalamus (failure of the regulatory centres). Patients taking physiological replacement doses of corticosteroids for either primary or secondary adrenal insufficiency are at significant risk of adrenal crisis and must be given stress doses of hydrocortisone during the peri-operative period. Many more patients other than those with adrenal and hypothalamic-pituitary causes of adrenal failure are receiving glucocorticoids as treatment for other medical conditions. Daily doses of prednisolone of 5 mg or greater in adults and 10-15 mg.m^-2 hydrocortisone equivalent or greater in children may result in hypothalamo-pituitary-adrenal axis suppression if administered for 1 month or more by oral, inhaled, intranasal, intra-articular or topical routes; this chronic administration of glucocorticoids is the most common cause of secondary adrenal suppression, sometimes referred to as tertiary adrenal insufficiency. A pragmatic approach to adrenal replacement during major stress is required; considering the evidence available, blanket recommendations would not be appropriate, and it is essential for the clinician to remember that adrenal replacement dosing following surgical stress or illness is in addition to usual steroid treatment. Patients with previously undiagnosed adrenal insufficiency sometimes present for the first time following the stress of surgery. Anaesthetists must be familiar with the symptoms and signs of acute adrenal insufficiency so that inadequate supplementation or undiagnosed adrenal insufficiency can be detected and treated promptly. Delays may prove fatal.

The safety of amoxicillin and clavulanic acid use during the first trimester of pregnancy

AIMS

The goal of the current study was to assess the risk for major congenital malformations following first-trimester exposure to amoxicillin, or amoxicillin and clavulanic acid (ACA).

METHODS

A population-based retrospective cohort study was conducted, by linking 4 computerized databases: maternal and infant hospitalization records, drug dispensing database of Clalit Health Services in Israel and data concerning pregnancy terminations. Multivariate negative-binomial regression was used to assess the risk for major malformations following first-trimester exposure, adjusted for mother's age, ethnicity (Bedouin vs Jewish), parity, diabetes mellitus, lack of perinatal care, and the year of birth.

RESULTS

The study included 101 615 pregnancies, of which 6919 (6.8%) were exposed to amoxicillin: 1045 (1.0%) to amoxicillin only and 6041 (5.9%) to ACA. No significant association was found, in the univariate and multivariate analyses, between first-trimester exposure to amoxicillin or ACA and major malformations in general (crude relative risk, 1.05 95% confidence interval 0.95-1.16; adjusted relative risk 1.09, 95% confidence interval 0.98-1.20), or for major malformations according to organ systems. No dose-response relationship was found between exposure in terms of the defined daily dose and major malformations.

CONCLUSION

Exposure to amoxicillin and ACA during the first trimester of pregnancy was not associated with an increased risk of major congenital malformations.

Pregnancy outcome following opioid exposure: A cohort study

INTRODUCTION

Opioids constitute a cornerstone of pain relief treatment. However, opioid safety during pregnancy has not been well established. Recent studies reported an association between in utero opioid exposure and spina bifida.

METHODS

In order to further evaluate the association of opioids exposure during pregnancy with adverse pregnancy outcomes, we conducted a large historical cohort by linking four databases: medications dispensations, births, pregnancy terminations for medical reasons and infant hospitalizations during the years of 1999-2009. Confounders that were controlled for included maternal age, ethnicity, maternal diabetes, smoking status, parity, obesity, year and folic acid intake. A secondary analysis for total major malformations and for spina bifida was performed using propensity score matching for first trimester exposure.

RESULTS

Of the 101,586 women included in the study, 3003 were dispensed opioids during the first trimester. Intrauterine exposure to opioids was not associated with overall major malformations (adjusted odds ratio (aOR) 0.97, 95% CI 0.83-1.13), cardiovascular malformations (aOR = 0.89, 95% CI 0.70-1.13) other malformations by systems or spina bifida in particular. However, the risk for spina bifida among newborns and abortuses who were exposed to codeine was four times higher than that of the unexposed (aOR = 4.42, 95% CI 1.60-12.23). This association remained significant in a secondary analysis using propensity score matching. Third trimester exposure to opioids was not associated with low birth weight (aOR = 1.08, 95% CI 0.77-1.52), perinatal death (aOR = 1.38, 95% CI 0.64-2.99) and other adverse pregnancy outcomes.

CONCLUSIONS

These findings suggest that opioids exposure (as a homogenous group) is not a significant risk factor for overall major malformations. Exposure to codeine during the first trimester was found to be associated with increased risk of spina bifida. However, this finding was based on a small number of cases and need to be verified in future work.

Infection prevention control and organisational patient safety culture within the context of isolation: study protocol

BACKGROUND

Healthcare associated infection (HCAI) is a major cause of morbidity and mortality. In recent years, there have been high profile successes in infection prevention control (IPC), such as the dramatic reductions in methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (which is viewed as one proxy indicator of overall harm) and Clostridium difficile in the UK. Nevertheless, HCAI remains a costly burden to health services, a source of concern to patients and the public and at present, is receiving priority from policy makers as it contributes to the global threat of antimicrobial resistance.

METHODS

The study involves qualitative case studies within isolation settings at two National Health Service (NHS) district general hospitals (DGHs) in Wales, in the UK. The 18-month study incorporates Manchester Patient Safety Framework (MaPSaF) workshops with health workers and other hospital staff, in depth interviews with patients and their relative / informal carer, health workers and hospital staff, and periods of hospital ward observation.

DISCUSSION

The present study aims to investigate the ways in which engagement of health workers with IPC strategies and principles, shape and inform organisational patient safety culture within the context of isolation in surgical, medical and admission hospital settings; and vice-versa. We want to understand the meaning of IPC 'ownership' for health workers; the ways in which IPC is promoted, how IPC teams operate as new challenges arise, how their effectiveness is assessed and the positioning of IPC within the broader context of organisational patient safety culture, within hospital isolation settings.

How to manipulate friends and influence practice: Application of complexity science leads to quality improvement in laboratory sample submissions

Background

We sought to reduce healthcare-associated infections (HCAIs) through the application of complexity science.

Objective

To confirm incidental findings that altering the structure of microbiology reports with targeted education led to better utilisation of laboratory resources, while participating in efforts to reduce HCAI.

Methods

We adopted a different approach to laboratory result authorisation, using narrative to engage the clinicians and induce behavioural change. Subsequent educational opportunities emphasised key messages.

Findings/Results

Positive urine means calculated by the analysis tool numbered 2179/month throughout the study period. Negative urines started at 5576/month, reduced to 5134/month in November 2014 and to 4602/month in April 2016, coinciding with our changes. Opportunity costs were saved.

Discussion

The changes in both policy and reporting were contemporaneous with a decline in negative samples. There were no significant changes in the number of positive specimens. The efficiency and effectiveness of the laboratory was improved and resources released: £145,000 ($182,000) for a resident population of 384,000. This suggests an annual release of about £25 million ($31 million) may be possible in the UK and £122 million ($155 million) in the USA.

Seasonality of birth affects paediatric coeliac disease

AIM

This study investigated the seasonality of birth in children diagnosed with coeliac disease (CD) at a tertiary University hospital in Southern Israel.

METHODS

This was a population-based retrospective time series analysis study from January 1988 to December 2014. There were 308 903 live births at Soroka University Medical Centre during the study period and 699 were diagnosed with CD. We combined three databases covering births, CD diagnoses and weather indices. The daily proportion of births that resulted in CD for the different four seasons and high seasons were compared to the weather indices on the day of birth using negative binomial regression.

RESULTS

Statistically significant associations were found between the season of birth and the rate of CD, with autumn births being associated with a higher risk for the development of CD than births during the summer, with an incidence ratio of 1.22. The association was further increased when the defined summer and autumn high seasons were used, with an incidence ratio of 1.40. No association was found between CD and the mean temperature and global radiation.

CONCLUSION

Coeliac disease was associated with birth during the autumn and the autumn high season posed an even more significant risk factor.

Abstract P3-06-18: Comprehensive genomic profiling of carcinosarcomas of the breast

Background:

Carcinosarcomas of the breast (BCSC) are exceptionally rare and the underlying genomic drivers are still being elucidated. Comprehensive genomic profiling (CGP) determines the tumor mutation burden (TMB) and identifies all four classes of genomic alterations (GA) that have potential to direct personalized treatment strategies.

Methods:

CGP by hybridization capture of exons from up to 315 cancer-related genes and select introns of 28 genes commonly rearranged in cancer was applied to ≥ 50ng of DNA extracted from 9 consecutive BCSC and sequenced to high, uniform median coverage (>500X). Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined by principal components analysis of optimized loci.

Results:

The 9 BCSC patients had a median age of 57 yrs (range 49-78 yrs). CGP was performed on the primary BCSC in 4 cases and on metastasis biopsies in 5 cases (4 lung and 1 lymph node). The mean GA/tumor was 6.6 and clinically relevant GA (CRGA)/tumor was 1.3. The most frequent non-CRGA were in TP53 (89%), MYC (56%) and LYN (40%). The most frequent CRGA were in PIK3CA (33%), and NF1, BRCA1, PTEN, RICTOR, FGFR1, AKT2 and STK11 (all at 11%). The median TMB for all BCSC was 2.4 mut/Mb with 1 (11%) tumor with a TMB > 20 mut/Mb and 8 BCSC (88%) with TMB < 5 mut/Mb. Five of 5 BCSC (100%) that were available for MSI status testing were microsatellite stable.

Conclusions:

On CGP, BCSC feature a high frequency of GA, but only a modest frequency of CRGA and high TMB. However, when the CRGA and TMB positive cases are combined (77.8% overall in this series), the opportunity for personalized targeted and immunotherapies are significant. Thus, further investigation of precision therapies for BCSC in the clinical trial setting appear warranted.

Citation Format: Gay LM, Elvin JA, Vergilio J-A, Killian JK, Ramkissoon S, Severson E, Daniel S, Hammerich A, Sokol E, Frampton G, Chung J, Trabucco S, Ali S, Reddy P, Schrock AB, Miller VA, Ross JS. Comprehensive genomic profiling of carcinosarcomas of the breast [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-06-18.

Risk of major congenital malformations following first-trimester exposure to vaginal azoles used for treating vulvovaginal candidiasis: a population-based retrospective cohort study

OBJECTIVE

To evaluate the risk for major malformations following first-trimester exposure to vaginal azoles.

DESIGN

A population-based retrospective cohort study of women exposed to vaginal azoles from the first day of the last menstrual period until the 90th gestational day.

SETTING

A combination of four computerised databases: medications, birth, infant hospitalizations, and pregnancy terminations.

POPULATION

All women who gave birth or underwent a pregnancy termination at Soroka Medical Center, Beer-Sheva, Israel, between 1999 and 2009.

METHODS

Crude and adjusted relative risks for major congenital malformations and for specific malformations according to organ systems were calculated using a multivariate negative binomial regression. Potential confounders were assessed and controlled for included parity, maternal age, ethnicity, maternal diabetes, smoking, and year of birth or pregnancy termination. Additional analysis using propensity score matching was performed for selected malformations.

MAIN OUTCOME MEASURES

Major malformations as well as specific malformations according to organ systems.

RESULTS

Of 101 615 pregnancies, 1993 (1.96%) were exposed to clotrimazole vaginal tablets and 313 (0.31%) to miconazole vaginal tablets during the first trimester of pregnancy. No association was found between first-trimester exposure to clotrimazole and major or specific malformations. An association was found between miconazole exposure and musculoskeletal malformation in general and other congenital musculoskeletal anomalies in particular. However, no association was detected when propensity score matching was used.

CONCLUSIONS

Intrauterine exposure to vaginal azoles during the first trimester of pregnancy was not associated with either major or specific malformations according to organ systems.

TWEETABLE ABSTRACT

First-trimester exposure to vaginal azoles is not associated with either major or specific malformations.

The Fetal Safety of Enoxaparin Use During Pregnancy: A Population-Based Retrospective Cohort Study

INTRODUCTION

Enoxaparin is widely used during pregnancy as pregnancy is a hypercoagulable state; however, its fetal safety has scarcely been investigated.

OBJECTIVE

Our study aimed to examine fetal safety following enoxaparin exposure during pregnancy.

METHODS

A population-based, retrospective cohort study was performed by linking computerized databases, including the drug dispensing registries of Clalit Health Services in Israel and maternal and infant hospital records, between 1998 and 2009. Multivariate logistic regression models were used to examine associations between first- and third-trimester exposure to enoxaparin, major malformations, and other adverse birth outcomes, adjusted for confounders.

RESULTS

From a total of 109,473 singleton pregnancies, 418 and 572 were exposed to enoxaparin during the first and third trimesters, respectively. Exposure to enoxaparin during the first trimester of pregnancy was not associated with an increased risk of major congenital malformations [adjusted odds ratio (aOR) 1.1, 95% confidence interval (CI) 0.8-1.6], while exposure during the third trimester was not associated with an increased risk of low birth weight (aOR 1.1, 95% CI 0.8-1.4), low Apgar score (aOR 0.9, 95% CI 0.4-1.8), or risk of perinatal mortality (aOR 0.6, 95% CI 0.1-2.9).

CONCLUSION

Exposure to enoxaparin during pregnancy was not associated with an increased risk of major malformations in general or according to organ systems. Nonetheless, risk for specific malformations cannot be ruled out.

Vaginal antimycotics and the risk for spontaneous abortions

BACKGROUND

Spontaneous abortions are the most common complication of pregnancy. Clotrimazole and miconazole are widely used vaginal-antimycotic agents used for the treatment of vulvovaginal candidiasis. A previous study has suggested an increased risk of miscarriage associated with these azoles, which may lead health professionals to refrain from their use even if clinically indicated.

OBJECTIVE

The aim of the current study was to assess the risk for spontaneous abortions following first trimester exposure to vaginal antimycotics.

STUDY DESIGN

A historical cohort study was conducted including all clinically apparent pregnancies that began from January 2003 through December 2009 and admitted for birth or spontaneous abortion at Soroka Medical Center, Clalit Health Services, Beer-Sheva, Israel. A computerized database of medication dispensation was linked with 2 computerized databases containing information on births and spontaneous abortions. Time-varying Cox regression models were constructed adjusting for mother's age, diabetes mellitus, hypothyroidism, obesity, hypercoagulable or inflammatory conditions, recurrent miscarriages, intrauterine contraceptive device, ethnicity, tobacco use, and the year of admission.

RESULTS

A total of 65,457 pregnancies were included in the study: 58,949 (90.1%) ended with birth and 6508 (9.9%) with a spontaneous abortion. Overall, 3246 (5%) pregnancies were exposed to vaginal antimycotic medications until the 20th gestational week: 2712 (4.2%) were exposed to clotrimazole and 633 (1%) to miconazole. Exposure to vaginal antimycotics was not associated with spontaneous abortions as a group (crude hazard ratio, 1.11; 95% confidence interval, 0.96-1.29; adjusted hazard ratio, 1.11; 95% confidence interval, 0.96-1.29) and specifically for clotrimazole (adjusted hazard ratio, 1.05; 95% confidence interval, 0.89-1.25) and miconazole (adjusted hazard ratio, 1.34; 95% confidence interval, 0.99-1.80). Furthermore, no association was found between categories of dosage of vaginal antimycotics and spontaneous abortions.

CONCLUSION

Exposure to vaginal antimycotics was not associated with spontaneous abortions.

Abstract P5-21-20: Integrating comprehensive genomic profiling with treatment decisions – Experience gained while treating 139 advanced breast carcinomas

Background: Comprehensive Genomic Profiling (CGP) using next-generation sequencing (NGS) technology can provide insight into potentially clinically relevant genomic alterations (CRGA) within a patient's breast cancer. For example, HER2 amplification status and targetable short variants (SV), acquired ESR1 or BRCA1/2 resistance mutations, and the presence of targetable alterations in the PI3K kinase. We retrospectively reviewed CGP results and subsequent outcomes at one cancer center to illustrate the experience of using molecular subtyping to inform treatment decisions.

Methods: DNA extracted from FFPE tumor tissue or blood samples obtained during routine clinical care for patients (n=139) with predominantly relapsed, refractory or metastatic breast cancer was analyzed by hybrid-capture, NGS for all classes of GA: 1. base substitutions, 2. insertion and deletions, 3. rearrangements, and 4. copy number changes. Treatment decisions based on comprehensive genomic profiles were captured retrospectively. Tumor mutational burden (TMB), scored as mutations (mut)/Mb, was calculated on 0.8-1.2 Mb of sequenced DNA. Alterations affecting the ERBB family included amplification of or oncogenic mutations in ERBB2 (HER2), ERBB3, and EGFR.

Results: From Jan 2013 to May 2017, FFPE tissue samples for 136 patients with advanced breast cancer were analyzed by CGP and 3 additional patients had circulating tumor DNA analyzed for alterations; 11 patients received profiling on multiple biopsies. Tumors analyzed were carcinomas (Ca) NOS (n=84), invasive ductal Ca (n=46), invasive lobular Ca (n=7), a neuroendocrine Ca, and a phyllodes tumor. In total, 118/139 (84.9%) samples harbored CRGA in a targetable pathway: PI3K/MTOR (n=67; 48.2%), CDK cell-cycle (n=40; 28.8%), ERBB family (n=24; 17.3%), FGFR (n=24; 17.3%), ESR1 (n=16; 11.5%), homologous repair (HRD)( n=14; 10.1%), and RAS/RAF/MEK (n=11; 7.9%). Targetable alterations in other cancer-related kinases were found in 10 (7.2%) samples and 10 (7.2%) samples were TMB high (≥20 mut/Mb) or had CD274 (PD-L1) amplification. There were 3 patients (2.1%) with HER2 short variants detected in the absence of ERBB2 amplification; these patients may respond to HER2-targeted therapies but would be HER2-negative by IHC. Many samples had alterations in ≥1 pathway, and overlap is particularly high for the CDK and FGFR pathways (12 samples). Alterations in pathways targeted by MTOR inhibitors, HER2-targeted therapies, or the CDK inhibitors were found in 93/136 (66.9%) tumors. Evaluation of outcomes for these 139 patients is ongoing and will be presented.

Conclusions: Genomic profiling of breast carcinomas, using either tissue or liquid biopsies, provides potentially actionable information to guide treatment decisions. Overall, 84.9% of patient samples harbored oncogenic alterations in a targetable pathway, with two-thirds of tumors having alterations in pathways targeted by therapies with FDA approval for breast cancer and 7.2% of patients having high levels of TMB or amplification of PD-L1, suggesting that checkpoint inhibitors may be relevant options.

Citation Format: Mahtani R, Gay LM, Chung J, Hartmaier R, Sokol E, Elvin JA, Daniel S, Ramkissoon S, Severson E, Suh J, Vergilio J-A, Stephens PJ, Ross JS. Integrating comprehensive genomic profiling with treatment decisions – Experience gained while treating 139 advanced breast carcinomas [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-20.

Abstract PD8-01: CDH1 mutated classic and pleomorphic invasive lobular breast carcinomas differ in genomic signatures and opportunities for targeted and immunotherapies

Background: Typically defined by negative IHC staining for E-cadherin, classic (CILC) and pleomorphic (PILC) are often combined as a single breast cancer subtype. We queried whether patients with relapsed metastatic disease, mCILC and mPILC, would harbor contrasting genomic alterations (GA)and that molecular information could further differentiate the 2 tumor types and thereby influence therapy selection.

Methods: DNA was extracted from 40 µm of FFPE sections of 10,784 invasive breast carcinomas. 454 (4%) CDH1 mutated mILC were selected including 428 classic mCILC (94%) and 26 mPLIC (6%) subtypes. Comprehensive genomic profiling (CGP) was performed on hybridization-captured, adaptor ligation-based libraries to a mean coverage depth >600X for up to 315 cancer-related genes. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA.

Results: mCILC and mPILC patients featured a median age of 63 years (Table). Slide based ER+ status and HER2+ status was significantly different in both groups (P<0.0001). The frequency of base substitutions in ESR1 was significantly higher in mCILC, and this difference was also significantly higher in mCILC metastasis biopsies exposed to hormonal therapy than in pre-treatment primary tumors (P<0.0001). ERBB2 (HER2) GA (amp + non-amp) detected by CGP were higher in mPILC than mCILC in both pre-and post-treatment samples (P<0.0001 for both). The ERBB2 GA frequency was nearly twice as high after hormonal therapy in both mCILC and mPILC. ESR1 and ERBB2 GA were mutually exclusive overall and especially in the mCILC group. PIK3CA GA were the most frequent GA in both mCILC and mPILC. TP53 GA were significantly more frequent in mPILC than mCILC. At 19%, the frequency of TMB > 15 mutations/MB in mPILC was more than twice as frequent than in mCILC (P=0.046). All (100%) of both the CILC and PILC groups were negative for mis-match repair deficiency or MSI high status. mCILC and mPILC patients with post primary therapy associated ESR1 and ERBB2 GA responding to targeted and immunotherapies will be presented.

Contrasting Clinical and Genomic Features of CILC and PILC Classic CILC (428 cases)Pleomorphic PILC (26 cases)Median Age6363*ER+98%74%*HER2 IHC/FISH+12 (3%)6 (22%)ESR1 GA Primary Pre-Rx6%0%ESR1 GA Metastatic Post-Rx17%0%ERBB2 GA Primary Pre-Rx7%18%ERBB2 GA Metastatic Post-Rx12%34%Other Significant GAPIK3CA (55%), CCND1 (21%), TP53 (17%), ARID1A, AKT3, MDM4, PTEN (all 11%)PIK3CA (58%), TP53 (30%), AKT1 22%), FGFR4, CCND1, PTEN (all 17%)TMB median (mut/Mb)2.73.6TMB > 15%8%19%*when clinical status available

Conclusions: CGP of mCILC and mPILC reveals significant differences in the panorama of GA both in pre-treatment primary and metastatic disease lesions especially in therapy-impacting GA in ESR1 and ERBB2. mCILC is more often driven by ESR1 GA and mPILC by ERBB2 GA. Although both mCILC and mPILC feature subsets of tumors with high TMB, this is more frequent for mPILC likely indicating different potentials for immunotherapies to benefit these patients.

Citation Format: Ross JS, Chung J, Elvin JE, Vergilio J-A, Ramkissoon S, Suh J, Severson E, Daniel S, Frampton GM, Fabrizio D, Hartmaier RJ, Albacker LA, Ali SM, Schrock AB, Miller VA, Stephens PJ, Gay LM. CDH1 mutated classic and pleomorphic invasive lobular breast carcinomas differ in genomic signatures and opportunities for targeted and immunotherapies [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD8-01.