Understanding General Surgery Recruitment and Attrition During the COVID-Era: A 1-Year Follow-Up Study

INTRODUCTION

The COVID-19 pandemic resulted in modifications to resident selection. The success of these new recruitment strategies as well as the impact on trainee attrition and competency is unknown. We previously evaluated how selection of general surgery applicants changed early in the pandemic. Here we supplement that work by reporting further modifications to the recruitment process and the perceived impact on resident attrition and competency.

METHODS

An anonymous cross-sectional survey sent via the Association of Program Directors in Surgery listserv in June 2022 to programs directors (PDs) at Accreditation Council for Graduate Medical Education accredited general surgery programs. Surveys contained demographic questions, 5-point Likert scale questions evaluating factors related to recruitment and match process, and postgraduate year 1 performance.

RESULTS

60 PDs responded to the survey. PDs continue to value the same post-COVID factors related to determining a resident's commitment to surgery but began to shift back to nonvirtual based strategies to recruit applicants in this new interview cycle. PD commentary frequently noted desire to return to in-person interviewing. 5.4% of postgraduate year 1s comprising this first class of residents who underwent virtual-only interviews and rotations did not reach Accreditation Council for Graduate Medical Education level 1 milestones, similar to prior years. The attrition rate amongst this class increased from 1.3% to 2.7%.

CONCLUSIONS

The attrition rate for postgraduate year 1 categorical general surgery residents has increased since the onset of the pandemic. The recruitment strategies adopted early in the pandemic have not maintained their initial perceived impact.

Association of Residency Applicants' Hobbies and Subsequent Technical Proficiency Ratings as General Surgery Chief Residents: A Multi-Institutional Study

OBJECTIVE

To determine whether participation in certain hobbies (e.g., participation in sports, playing musical instruments, or other hobbies requiring fine motor skills), preresidency, are associated with higher technical skills ratings at the time of residency graduation.

DESIGN

Faculty members from 14 general surgery residency programs scored individual graduates from 2017 to 2020 on their technical skills using a 5-point Likert scale. Hobbies for these residents were collected from their Electronic Residency Application Service (ERAS) data. A single reviewer classified each ERAS hobby into predefined categories including musical instruments, sports requiring hand-eye coordination, team sports, and activities necessitating hand-eye coordination. Spearman correlation coefficients were calculated for the relationship between each category of hobby-as well as the total number of hobbies in each category-and the outcome of surgical faculty ratings of residents' technical surgical skills during their last year of residency. A proportional odds model including the above predictive variables was also fit to the data.

SETTING

Fourteen general surgery residency programs.

PARTICIPANTS

General surgery residency graduates from 14 different programs from 2017 to 2020.

RESULTS

There were 296 residents across 14 institutions. The average ranking of residents' technical skills was 3.24 (SD 1.1). A total of 40% of residents played sports involving hand-eye coordination, 31% played team sports, 28% participated in nonsport hobbies that require eye-hand coordination, and 20% played musical instruments. Correlation coefficients were not statistically significant for any of the categories. In the proportional odds model, none of the variables were associated with statistically significant increased odds of a higher technical skills rating.

CONCLUSIONS

There was no correlation between general surgery chief residents' technical skills as rated by faculty, and self-reported pre-residency hobbies on the ERAS application. These findings suggest such hobbies prior to residency are unlikely to predict future technical skills prowess.

Smaller Differences in the Comparative Effectiveness of Biologics in Reducing Asthma-Related Hospitalizations Compared With Overall Exacerbations

BACKGROUND

Evidence on the comparative effectiveness of respiratory biologics remains sparse.

OBJECTIVE

We sought to evaluate the comparative effectiveness of omalizumab, mepolizumab, benralizumab, and dupilumab in a matched retrospective cohort of patients with asthma.

METHODS

We identified patients with asthma aged ≥18 years who were incident users of these biologics between November 1, 2018, and June 30, 2023, in administrative claims data from the Food and Drug Administration's Sentinel System and Merative MarketScan Commercial Database. We compared asthma-related exacerbations and hospitalizations in the 12 months since biologic prescription in pairwise comparisons of propensity score-matched cohorts. Covariates used in matching included age, sex, allergic comorbidities, baseline asthma medications use, and the Charlson Comorbidity Index. Incidence rate ratios (IRR) and 95% confidence intervals (CI) were estimated using negative binomial regression models.

RESULTS

A total of 893 patients on mepolizumab, 1300 on benralizumab, 1170 on omalizumab, and 1863 on dupilumab were identified. The average age was 55 years, and two-thirds of the participants were female. At baseline, over 80% of these individuals had an active prescription for an inhaled corticosteroid. Almost half of patients on dupilumab had concomitant nasal polyposis compared with 6% to 13% of patients on the other biologics. Covariates were balanced after matching. In matched analyses, dupilumab was associated with the lowest incidence of exacerbations over the follow-up period (vs dupilumab): mepolizumab (IRR: 1.36; 95% CI: 1.12, 1.64), omalizumab (IRR: 1.33; 95% CI: 1.13, 1.58), benralizumab (IRR: 1.19; 95% CI: 1.00, 1.41). For exacerbations leading to hospitalizations, benralizumab and mepolizumab were associated with the lowest incidence of hospitalizations, and the greatest difference was between mepolizumab versus dupilumab (IRR: 0.76; 95% CI: 0.56, 1.03).

CONCLUSIONS

Dupilumab was associated with the lowest incidence of overall exacerbations, and mepolizumab with the lowest incidence of asthma hospitalizations in this administrative claims-based cohort of individuals with asthma. Despite matching propensity scores, residual confounding, such as baseline eosinophil count, may explain some of these findings.

Gender Differences in Autonomy Granted to Residents and Fellows During Procedural Training: A Systematic Review and Meta-Analysis

PURPOSE

Supervisors may be prone to implicit (unintentional) bias when granting procedural autonomy to trainees due to the subjectivity of autonomy decisions. The authors aimed to conduct a systematic review and meta-analysis to assess the differences in perceptions of procedural autonomy granted to physician trainees based on gender and/or race.

METHOD

MEDLINE, Embase, CENTRAL, Scopus, and Web of Science were searched (search date: January 5, 2022) for studies reporting quantitative gender- or race-based differences in perceptions of procedural autonomy of physician trainees. Reviewers worked in duplicate for article selection and data abstraction. Primary measures of interest were self-reported and observer-rated procedural autonomy. Meta-analysis pooled differences in perceptions of procedural autonomy based on trainee gender.

RESULTS

The search returned 2,714 articles, of which 16 were eligible for inclusion. These reported data for 6,109 trainees (median 90 per study) and 2,763 supervisors (median 54 per study). No studies investigated differences in perceptions of autonomy based on race. In meta-analysis of disparities between genders in autonomy ratings (positive number favoring female trainees), pooled standardized mean differences were -0.12 (95% confidence interval [CI] = -0.19, -0.04; P = .003; n = 10 studies) for trainee self-rated autonomy and -0.05 (95% CI = -0.11, 0.01; P = .07; n = 9 studies) for supervisor ratings of autonomy.

CONCLUSIONS

Limited evidence suggests that female trainees perceived that they received less procedural autonomy than did males. Further research exploring the degree of gender- and race-based differences in procedural autonomy, and factors that influence these differences, is warranted.

Investigation of High Molecular Weight Size Variant Formation in Antibody-Drug Conjugates: Microbial Transglutaminase-Mediated Crosslinking

Microbial transglutaminase (mTG) has become a powerful tool for manufacturing antibody-drug conjugates (ADCs). It enables site-specific conjugation by catalyzing formation of stable isopeptide bond between glutamine (Q) side chain and primary amine. However, the downstream impact of mTG-mediated conjugation on ADC product quality, especially on high molecular weight (HMW) size variant formation has not been studied in a systematic manner. This study investigates the mechanisms underlying the formation of HMW size variants in mTG-mediated ADCs using size exclusion chromatography (SEC) and liquid chromatography-mass spectrometry (LC-MS). Our findings revealed that the mTG-mediated glutamine and lysine (K) crosslinking is the primary source of the increased level of HMW size variants in the ADCs. In the study, two monoclonal antibodies (mAbs) with glutamine engineered for site-specific conjugation were used as model systems. Based on the LC-MS analysis, a single lysine (K56) in the heavy chain (HC) was identified as the major Q-K crosslinking site in one of the two mAbs. The HC C-terminal K was observed to crosslink to the target Q in both mAbs. Quantitative correlation was established between the percentage of HMW size variants determined by SEC and the percentage of crosslinked peptides quantified by MS peptide mapping. Importantly, it was demonstrated that the level of HMW size variants in the second ADC was substantially reduced by the complete removal of HC C-terminal K before conjugation. The current work demonstrates that crosslinking and other side reactions during mTG-mediated conjugation needs to be carefully monitored and controlled to ensure process consistency and high product quality of the final ADC drug product.

Analysis of COVID-19 Case Demographics and Disease Outcomes in Gary, Indiana

BACKGROUND

The COVID-19 pandemic further exposed the prevalence of existing health disparities in Black communities in the U.S. The current study evaluates COVID-19 data collected in Gary, Indiana, from June 2020 to June 2021. We hypothesized that the number of COVID-19 cases, hospitalizations, and deaths were influenced by race and income.

METHODS

In collaboration with the Gary Health Department (GHD), we analyzed demographic data on COVID-19-positive cases.

RESULTS

Compared to Gary's non-Black population, age- and population-adjusted rates of hospitalizations and deaths in the Black population were 3-fold (p < 0.0001) and 2-fold (p < 0.05) higher, respectively. This is despite a higher infection rate (p < 0.0001) in the non-Black population. The median household income of a zip code was negatively correlated with COVID-19 hospitalizations (R2 = 0.6345, p = 0.03), but did not correlate with infections and deaths.

CONCLUSIONS

The current study demonstrates clear health disparities of income and race in the context of COVID-19-related infections and outcomes in the city of Gary. Indiana University School of Medicine Northwest and GHD officials can collaborate to utilize these data for the reallocation of resources and health education efforts in Gary's highly populated, low-income, and predominantly Black neighborhoods. It should also prompt further investigation into national health resource allocation.

Development of Novel Glucocorticoids for Use in Antibody-Drug Conjugates for the Treatment of Inflammatory Diseases

Glucocorticoids (GCs) are widely used to treat a variety of autoimmune and inflammatory diseases; however, systemic delivery of GCs is associated with side effects that affect essentially every organ system, reflecting the nearly ubiquitous expression of the glucocorticoid receptor (GR). Targeted delivery of GCs to diseased tissues using antibody-glucocorticoid conjugates (GC-ADCs) offers a therapeutic alternative to overcome these adverse effects. Herein, we describe novel classes of GCs that exhibited greater potency than dexamethasone and budesonide, a 100-fold selectivity toward the GR over other nuclear receptors, and no in vitro safety liability in pharmacology assays (hERG, AMES) and that demonstrated a substantial reduction in tumor necrosis factor-α (TNF-α) release in mice challenged with lipopolysaccharide (LPS). The site-specific conjugated GC-ADCs via cathepsin-cleavable linkers were highly stable in plasma and specifically released GCs in antigen-positive cells, suggesting that these novel GCs can serve as ADC payloads to treat autoimmune and inflammatory diseases.

Value of Standardized Testing in Surgical Training

Standardized testing remains a cornerstone of assessment in surgical education. Summative standardized tests make up a bulk of the certification requirements that encompasses demonstration of efficient, safe application of clinically relevant surgical knowledge and skills. Formative standardized tests serve similar role to guide teaching endeavors for the programs and comparison of individual trainees on a national level. Ongoing rigorous psychometric evaluations of the standardized tests ensure reliability and validity; however, standardized tests are not without their limitations and biases.

Abstract 2611: Transcription factor-nucleosome dynamics inferred from plasma cfDNA delineates tumor and tumor-microenvironment phenotype

Our current understanding of solid tumors and their progression primarily relies on in vitro models, cell lines, patient-derived xenografts, and scarce data from invasive tissue biopsies from patients. The ability to monitor changes in chromatin structure and transcription factor binding in tumor cells using a minimally invasive approach in humans has the potential to revolutionize our understanding of disease progression and treatment resistance. In this study, we use the example of estrogen receptor (ER) positive breast cancer, the most common disease subtype, and define the ER axis from plasma cell-free DNA (cfDNA). While lymphoid/myeloid cell turnover represents the dominant source of cfDNA in the bloodstream, a detectable fraction of DNA from tumor tissue-of-origin can be found in patients with solid cancers. cfDNA is the product of the action of endogenous nucleases on chromatin; and retains the map of epigenomes from cells of origin. Our method therefore non-invasively captures TF-nucleosome dynamics in tumor tissue-of-origin using plasma cfDNA. First, we show that we can reliably identify the active binding of hematopoietic pioneer factor PU.1 and CTCF from cfDNA of healthy humans and cancer patients. Then to define cfDNA binding of disease specific TF ER, we used ER+ patient-derived xenograft (PDX) models allowing for a clear separation of tumor signal from hematopoietic background. This allowed us to establish the sensitivity and specificity of our approach. We also identified the subset of CUT&RUN-defined ER binding sites that feature the strongest binding in vivo from both lymphocyte background as well as cancer cells. Furthermore, we can define the active binding sites of pioneer factor FOXA1, which facilitates ER binding by opening the chromatin. Based on the TF protection levels from cfDNA we were able to define tumor as well as hematopoietic-specific TF binding sites that can serve as potential hotspots to monitor ER+ disease state at around 1% tumor fraction. These data demonstrate our ability to simultaneously monitor TF and nucleosome dynamics at disease sites just from plasma that can enable real-time monitoring of disease phenotype in a minimally invasive manner.

Citation Format: Satyanarayan Rao, Amy Han, Alexis Zukowski, Etana Kopin, Peter Kabos, Srinivas Ramachandran. Transcription factor-nucleosome dynamics inferred from plasma cfDNA delineates tumor and tumor-microenvironment phenotype [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 2611.

Abstract 2116: Promoter enrichment of subnucleosomes using breast cancer cell-free DNA

Breast cancer is the leading cancer diagnosis and the second major cause of cancer-related deaths in women worldwide. The use of non-invasive cell-free DNA (cfDNA) to detect and assess cancer dynamics has recently gained traction with a focus on targeted mutation panels. However, mutation panels have to contend with non-tumor origin of mutations like clonal hematopoiesis and the emergence of novel mutations in the tumor. A potential alternative is to harness the epigenomic, or non-genetic, features of cfDNA. In a healthy individual, blood cell turnover is the major contributor to the cfDNA pool. In cancer, tumor DNA adds to the cfDNA pool, which represents the end product of endogenous nucleases acting on accessible genomic DNA. Since genomic DNA is protected by histone proteins, cfDNA maps the chromatin structure of individual cells that turn over. Subnucleosomes (partially formed structures of nucleosomes that are the building blocks of chromatin) are by-products of transcription and thus reflect small protections enriched in active genes. The enrichment of subnucleosomes at promoters correlate with gene expression profiles of cfDNA tissues-of-origin and based on this knowledge, we hypothesized that we could reconstruct the transcriptional profiles of cancer cells by selectively targeting promoter regions. We first extracted cfDNA from 9 healthy female donors and 8 patient donors with various stages of breast cancer (Stage I, n=1; Stage III, n=1; Stage IV, n=4). We used a single-stranded DNA library protocol that robustly captures highly nicked cfDNA, enabling the genome-wide mapping of both nucleosomes and subnucleosomes. We performed targeted capture of promoter-proximal, nucleosome-protected sequences in cfDNA using non-overlapping tiling probes from transcription start sites to 300 bp downstream. After whole-genome sequencing of pooled libraries, we show that 76.4% (n=13/17) of samples exhibited &gt;10X enrichment compared to unenriched samples, and 64.7% (n=11/17) of samples exhibited &gt;100X enrichment. The enriched samples allowed us to profile &gt;10,000 genes, whereas unenriched samples enabled profiling between 100-10,000 genes at an average sequencing depth of 40 million reads. Overall, we obtain higher depth per sequencing read after enrichment resulting in a high-resolution snapshot of promoter-nucleosome dynamics derived by probing only ~0.18% of the genome. We believe that this significant advancement will allow us not only to identify presence of cancer but also detect distinct tumor states.

Citation Format: Alexis Zukowski, Amy Han, Peter Kabos, Srinivas Ramachandran. Promoter enrichment of subnucleosomes using breast cancer cell-free DNA [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 2116.

Dissecting the Role of VicK Phosphatase in Aggregation and Biofilm Formation of Streptococcus mutans

VicRK (WalRK or YycFG) is a conserved 2-component regulatory system (TCS) that regulates cell division, cell wall biosynthesis, and homeostasis in low-GC Gram-positive bacteria. VicRK is also associated with biofilm formation of Streptococcus mutans on the tooth surface as it directly regulates the extracellular polysaccharide (EPS) synthesis. Of the 2 components, VicK possesses both autokinase and phosphatase activities, which regulate the phosphorylation and dephosphorylation of the regulator VicR in response to environmental cues. However, the dual mechanism of VicK as the autokinase/phosphatase in regulating S. mutans' responses is not well elucidated. Previously, it has been shown that the phosphatase activity depends on the PAS domain and residues in the DHp domain of VicK in S. mutans. Specifically, mutating proline at 222 in the PAS domain inhibits VicK phosphatase activity. We generated a VicK^P222A mutant to determine the level of VicR-P in the cytoplasm by Phos-tag sodium dodecyl sulfate polyacrylamide gel electrophoresis. We show that in VicK^P222A phosphatase, attenuation increased phosphorylated VicR (VicR-P) that downregulated glucosyltransferases, gtfBC, thereby reducing the synthesis of water-insoluble polysaccharides (WIS-EPS) in the biofilm. In addition, VicK^P222A presented as long-rod cells, reduced growth, and displayed asymmetrical division. A major adhesin of S. mutans, SpaP was downregulated in VicK^P222A, making it unable to agglutinate in saliva. In summary, we have confirmed that VicK phosphatase activity is critical to maintain optimal phosphorylation status of VicR in S. mutans, which is important for cell growth, cell division, EPS synthesis, and bacterial agglutination in saliva. Hence, VicK phosphatase activity may represent a promising target to modulate S. mutans' pathogenicity.

Efficacy of Virtual Case-Based General Surgery Clerkship Curriculum During COVID-19 Distancing

OBJECTIVE

The COVID-19 pandemic created a paradigm shift in medical education with a reliance upon alternative teaching methods to deliver meaningful surgery clerkship content. This study examines the efficacy of a novel, case-based virtual surgery clerkship curriculum to determine its impact on student experience during quarantine.

STUDY DESIGN

Sixteen third-year medical students enrolled in the General Surgery clerkship between April through June 2020 during COVID-19 distancing at a quaternary medical center (Cleveland Clinic, Cleveland, OH) participated in this study. Course surveys, including a 10-question curriculum-based multiple-choice assessment, were administered before and after the clerkship. Analyses include student self-perception of readiness to see a surgical consult independently, students' interest in pursuing a General Surgery residency, and improvement of surgical knowledge.

RESULTS AND CONCLUSION

On a 5-point Likert scale, students felt significantly more assured in their ability to independently assess a surgical consult by the end of the course. Five (31%) students reported an influence of the curriculum on their personal interest in a career in General Surgery. Mean scores on the curriculum-based knowledge assessment increased. These findings highlight that a virtual platform can be a reliable alternative adjunct that delivers surgical content and positively impacts student experience.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40670-020-01126-5.

Abstract 2898: A biparatopic HER2xHER2 antibody drug conjugate with potent anti-tumor activity

A biparatopic HER2xHER2 antibody drug conjugate with potent anti-tumor activity.

The antibody drug conjugate (ADC) Trastuzumab-emtansine (T-DM1) targets the well-characterized breast cancer oncogene HER2 and is active in tumors that express very high levels of HER2 protein. However, tumors expressing intermediate levels of HER2 remain resistant to T-DM1 therapy, apparently due to insufficient lysosomal trafficking of T-DM1. We generated a series of biparatopic HER2xHER2 antibodies in which each arm recognizes a distinct epitope of HER2. One of our HER2xHER2 antibodies bound to cells with greater avidity than Trastuzumab and formed visible cell surface clusters that were efficiently internalized. While some of the internalized HER2xHER2 antibody trafficked to lysosomes and promoted HER2 degradation, a significant fraction recycled back to the plasma membrane through recycling endosomes. To exploit the increased internalization and recycling of the HER2xHER2 antibody, ADCs were generated by site-specific conjugation of Tubulysin A payload through a protease-cleavable linker. Recent data suggest that cleavage of this linker does not require lysosomal trafficking, but can occur in recycling endosomes as well. HER2xHER2-Tubulysin killed cell lines expressing high (IHC3+) and intermediate (IHC2+) HER2 levels with subnanomolar IC50, while exhibiting very weak killing of cells expressing low (IHC1+) HER2 levels (IC50 greater than 10nM). HER2xHER2-Tubulysin induced complete and durable tumor regression and outperformed T-DM1 in a collection of IHC3+ and 2+ tumor xenograft models (including PDX). Our work shows that a detailed understanding of antibody trafficking can enable the design of more effective ADCs and suggests that HER2xHER2-Tubulysin is a potential clinical candidate for HER2 IHC2+ breast cancer.

Citation Format: Andres Perez Bay, Devon Faulkner, Shiwani Tiwari, Carla Castanaro, Xiang Zheng, Arthur Kunz, Thomas Nittoli, Amy Han, William Olson, Gavin Thurston, Christopher Daly, Julian Andreev. A biparatopic HER2xHER2 antibody drug conjugate with potent anti-tumor activity [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 2898.

Characterizing patient-clinician chemotherapy-induced peripheral neuropathy assessment and management communication approaches

OBJECTIVE

To describe the frequency and characteristics of chemotherapy-induced peripheral neuropathy (CIPN) assessment and management communication approaches between patients receiving neurotoxic chemotherapy and clinicians.

METHODS

The data used in this analysis originated from a randomized controlled trial in which adults with cancer self-reported treatment-related symptoms using web-based symptom assessment technology. Three-to-six weeks after study initiation, each participant's outpatient visit was audio-recorded. Audio recordings and associated clinician notes for 159 participants who received platinum and/or taxane-based chemotherapy were coded for the presence of several CIPN assessment and management communication characteristics.

RESULTS

Participants received low cumulative neurotoxic chemotherapy doses (75%) at the time of audio recording. CIPN was discussed and documented in 44% and 46% of participant-clinician encounters. In symptomatic participants, clinicians asked an average of 0.7 open-ended questions, appropriately managed 70% of cases, and asked upper and lower extremity CIPN questions in 25% of cases.

CONCLUSIONS

Clinicians infrequently discussed and documented CIPN in participants with low CIPN severity, however appropriately managed mild CIPN. Development of interventions to translate existing recommended CIPN communication approaches into practice are required.

PRACTICE IMPLICATIONS

Effective participant-clinician communication is required at each clinic visit during chemotherapy treatment to identify initial signs of CIPN and offer appropriate treatment.

Abstract P6-17-15: Evaluating preclinical efficacy of anti-HER2 drug combinations using ER+/HER2 mutant models

Background

Until recently, HER2 gene amplification was the only mechanism of HER2 activation recognized. However, activating HER2 mutations have been noted in different cancer types. A trials of HER2 mutant breast cancer and the subsequent SUMMIT trial data have shown that monotherapy with the pan-HER drug neratinib as showed clinical efficacy, but with poor response durability. This study therefore investigates the preclinical efficacy of anti HER2 agents alone or in combination with endocrine therapy agents or in combination with CDK4/6 inhibitors using ER+/HER2 mutant cell lines and ex vivo HER2 mutant patient derived xenograft (PDX) model to define a more effective treatment approach.

Methods

ER+ breast cancer cell lines (T47D and MCF7) stably expressing HER2V777L, and ER+/HER2 mutant PDX model (HER2G778_P780 dup) were used to examine HER2 signaling and drug responses. Signaling downstream mutant HER2 was examined by immunoblot analysis. Effects of neratinib alone, neratinib + fulvestrant, and neratinib + abemaciclib on cell growth were examined in ER+/HER2 mutant cell lines and in an ex vivo HER2G778_P780 dup.

Results

We found that MCF7/T47D cells expressing HER2V777L and HER2G778_P780 dup PDX tumors showed strongly activated autophosphorylation of HER2 and increased expression of CDK4, CDK6, phospho-Rb, and cyclin D1 as compared to MCF7/T47D cells expressing HER2WT or ER+/non-HER2mut PDX modes, suggesting that HER2 mutations preferentially depend on CDK4/6 signaling for cell growth. Additionally, we showed that activating MCF7 HER2 V777L cause resistance to endocrine therapy treatment (fulvestrant IC50 &gt;5μM). Further, we show that neratinib alone is effective at higher concentrations (IC50 &lt; 2μM) in MCF7/HER2 V777L cells. We also demonstrate that abemaciclib alone exhibited moderate activity against MCF7 HER2 V777L cells (IC50 &lt; 0.4μM) and additional activity in combination with neratinib (IC50 &lt; 0.06μM) was seen. Moreover, ex vivo HER2 G778_P780 dup cells are relatively resistant to fulvestrant alone (IC50 &lt; 0.2μM), neratinib alone (IC50 &lt; 0.006μM), abemaciclib alone (IC50 &lt; 0.04μM), and neratinib in combination with abemaciclib (IC50 &lt; 0.005μM), suggesting that patients harboring ER+/HER2-mutant tumors may benefit from neratinib in combination with abemaciclib.

Conclusion

These preclinical data suggest that neratinib monotherapy may not be effective to treat ER+/HER2 mutant patients and we propose that simultaneous targeting of both HER2 and the CDK4/6 axis will be required for effective treatment of ER+ breast cancers harboring HER2 activating mutations.

Citation Format: Kavuri SM, Devarakonda V, Williams LC, Seker S, Lei JT, Singh P, Han A, Anurag M, Holloway KR, Welm AL, Ellis MJ. Evaluating preclinical efficacy of anti-HER2 drug combinations using ER+/HER2 mutant models [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 P6-17-15.

Abstract P5-08-01: DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer

Proteogenomics is the field of integrating data from mass spectrometry-based shotgun proteomics, and phosphoproteomics into next-generation RNA and DNA sequencing data analysis pipelines that promises new insights into cancer biology and therapeutic targeting. As well as analyses of clinical samples for disease phenotype association analysis, the application of proteogenomics to model systems also has considerable potential. A Clinical Proteomic Tumor Analysis Consortium (CPTAC) proteogenomic analysis prioritized dihydropyrimidinase-like-3 (DPYSL3) as a multi-level (RNA/Protein/Phosphoprotein) expression outlier specific to the Claudin-Low (CLOW) subset of triple negative breast cancers. A Pubmed informatics tool indicated a paucity of data in the context of breast cancer which further prioritized DPYSL3 for study.

DPYSL3 was identified as a protein that is regulated during neuronal differentiation in the cerebral cortex and in neuronal cell lines and plays a role in regulating neurite outgrowth somehow through an association with vesicles in the growth cone. In addition, DPYSL3 expression has been observed in several malignant tumors, including prostate cancer, pancreatic cancer, gastric cancer and neuroblastoma. DPYSL3 is reported to play a role in cell migration and metastasis suppression in prostate cancer. However, in pancreatic cancer, DPYSL3 is positively associated with liver metastasis and poor outcome.

DPYSL3 knock-down in DPYSL3 (+) CLOW cell lines demonstrated reduced proliferation, yet enhanced motility and increased expression of Epithelial to Mesenchymal Transition (EMT) markers suggesting that DPYSL3 is a multi-functional signaling modulator. Slower proliferation in DPYSL3 (-) CLOW cells was associated with accumulation of multi-nucleated cells indicating a mitotic defect that was associated with a collapse of the vimentin (VIM) microfilament networkinduced by VIM hyperphosphorylation. On the other hand, DPYSL3 suppressed the expression of EMT regulators TWIST and SNAIL and opposed p21 activated kinase 2 (PAK2) dependent migration, but these EMT regulators in turn induced DPYSL3 expression, suggesting DPYSL3 participates in negative feedback in EMT. Cell migration in DPYSL3 (-) cells correlated with increased phosphorylation of PAK2 on Ser20 and was sensitive to PAK2 siRNA and pharmacological PAK inhibition.Immunoprecipitation and mass spectrometry-based proteomics or western blotting strongly suggests that PAKs interact such that DPYSL3 may function as a direct negative regulator of PAK family kinases. Thus, a PAK inhibitor could potentially mitigate increase migration as an adverse effect of DPYSL3 suppression.

In conclusion, DPYSL3 is a remarkable multifunctional signaling scaffold that should be examined further to provide insights into the stem cell-like state of claudin-low breast cancers, particularly in terms of their cell cycle dependencies, migratory activity and capacity for EMT.

Citation Format: Matsunuma R, Chan DW, Kim B-J, Singh P, Han A, Saltzman A, Cheng C, Lei JT, Sahin E, Leng M, Fan C, Perou CM, Malovannaya A, Ellis MJ. DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer [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 P5-08-01.

Macromolecular crowding tunes 3D collagen architecture and cell morphogenesis

Collagen I is the primary extracellular matrix component of most solid tumors and influences metastatic progression. Collagen matrix engineering techniques are useful for understanding how this complex biomaterial regulates cancer cell behavior and for improving in vitro cancer models. Here, we establish an approach to tune collagen fibril architecture using PEG as an inert molecular crowding agent during gelation and cell embedding. We find that crowding produces matrices with tighter fibril networks that are less susceptible to proteinase mediated degradation, but does not significantly alter matrix stiffness. The resulting matrices have the effect of preventing cell spreading, confining cells, and reducing cell contractility. Matrix degradability and fibril length are identified as strong predictors of cell confinement. Further, the degree of confinement predicts whether breast cancer cells will ultimately undergo individual or collective behaviors. Highly confined breast cancer cells undergo morphogenesis to form either invasive networks reminiscent of aggressive tumors or gland and lobule structures reminiscent of normal breast epithelia. This morphological transition is accompanied by expression of cell-cell adhesion genes, including PECAM1 and ICAM1. Our study suggests that cell confinement, mediated by matrix architecture, is a design feature that tunes the transcriptional and morphogenic state of breast cancer cells.

Abstract 477: Targeting of ErbB3 with functional cooperative miRNAs enhances efficacy of trastuzumab in ErbB2-overexpressing breast cancer cells

Introduction: ErbB3 serves as a critical co-receptor of erbB2 and plays a vital role in the development of erbB2-overexpressing (erbB2+) breast cancer. It is thought to be an important compensatory target for combinatorial strategy to improve the treatments for erbB2+ breast cancer patients. MiRNAs regulate gene expression by the sequence-specific targeting of mRNAs, leading to translational repression or mRNA degradation. ErbB3 is a direct target of both miR-125a and miR-205. Here, we study the potential activity of miRNA based erbB3-targeted therapy in erbB2+ breast cancer cells.

Methods: Cell growth assays were used to determine cell viability. Western blot analyses were performed to assess the expression and activation of proteins. Flow cytometry analysis was carried out to examine cell cycle progression. Lentiviral vector containing one or two miRNAs was used to ectopically express miR-125a and/or miR-205.

Results: Co-expression of miR-125a and miR-205 showed a potent activity to downregulate erbB3 while single miRNA had no or little effect on erbB3 when miR-125a or miR-205 was only increased below 10-fold in BT474 cells. Combination of the two miRNAs not only resulted in a dramatic reduction of phosphorylated erbB3 (P-erbB3) and the downstream signaling kinases Akt (P-Akt) and Src (P-Scr), it also inhibited cell proliferation and increased the cells at G1 phase. More importantly, concomitant expression of the two miRNAs significantly enhanced trastuzumab-mediated growth inhibition and cell cycle G1 arrest in BT474 cells. Interestingly, the expression levels of miR-125a, but not miR-205 in the trastuzumab-resistant BT474-HR20 cells were much lower than that in the parental BT474 cells. Ectopic expression of miR-125a alone profoundly inhibited proliferation of BT474-HR20 cells. These data suggested that reduced miR-125a might be a novel mechanism leading to trastuzumab resistance; and upregulation of miR-125a could be a useful tool to abrogate the resistance.

Conclusions: Co-expression of miR-125a and miR-205 is a new approach to inhibit erbB3. Specific targeting of erbB3 via the functional cooperative miRNAs enhances efficacy of trastuzumab against erbB2+ breast cancer cells. Our data support further exploration of the possible role of miR-125a in the development of trastuzumab resistance.

Keywords: ErbB3, ErbB2, miRNA, Trastuzumab, Breast Cancer

Citation Format: Hui Lyu, Jingcao Huang, Bolun Wang, Amy Han, Bolin Liu. Targeting of ErbB3 with functional cooperative miRNAs enhances efficacy of trastuzumab in ErbB2-overexpressing breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 477.

Analysis of Two Quantitative Ultrasound Approaches

There are two well-known ultrasonic approaches to extract sets of quantitative parameters: Lizzi-Feleppa (LF) parameters: slope, intercept, and midband; and quantitative ultrasound (QUS)-derived parameters: effective scatterer diameter (ESD) and effective acoustic concentration (EAC). In this study, the relation between the LF and QUS-derived parameters is studied theoretically and experimentally on ex vivo mouse livers. As expected from the theory, LF slope is correlated to ESD ([Formula: see text]), and from experimental data, LF midband is correlated to EAC ([Formula: see text]). However, LF intercept is not correlated to ESD ([Formula: see text]) nor EAC ([Formula: see text]). The unexpected correlation observed between LF slope and EAC ([Formula: see text]) results likely from the high correlation between ESD and EAC due to the inversion process. For a liver fat percentage estimation, an important potential medical application, the parameters presenting the better correlation are EAC ([Formula: see text]) and LF midband ([Formula: see text]).

Abstract P5-06-01: Proteomic analysis of conserved kinases between PDX tumors and corresponding PDX-derived cell lines

(Background) Patient-derived xenograft (PDX)s are valuable models for precision oncology as they are thought to recapitulate the biological and genomic characteristics of the human tumors they were derived from. Even though this model is widely used, it is still difficult to manipulate genes in this system and it is not as convenient as in vitro cell culture for drug sensitivity screening. On the other hand in vitro cell cultures have a highly artificial microenvironment and also have undergone selection which might generate misleading data. To address these issues cell lines from PDX tumors with different intrinsic subtypes were characterized by kinobead precipitation/mass spectrometry analysis (KiP/MS) to profile each PDX line in vivo and ex vivo for therapeutic targets.

(Materials and Methods)Washington University Human in Mice (WHIM) tumors and Hutsman Cancer Institute (HCI) tumors were transplanted into mammary fat pads of female severe combined immunodeficiency/beige (SCID/beige) mice. PDXs tumors were harvested when they reached 1˜1.5cm. PDX tumor-derived ex vivo cells/organoids were routinely cultured with Rock inhibitor support. Estradiol was applied only for the tumors originating from E2 supplementation in vivo. Cells and tumors were harvested and lysed by sonication. Kinases in soluble lysates are enriched with drug-bound beads (kinobead) and digested with trypsin. Digested peptides are analyzed by mass spectrometry.

(Results) 5 of WHIM tumors and 4 of HCI tumors were successfully dissociated and cultured ex vivo for further analysis and experiments. Hierarchical clustering of tumors and corresponding cells showed ex vivo cultured cells cluster together with their original PDX tumors. Tumors/ex vivo cultured cells clustered by intrinsic subtype and enrichment analysis identified specific kinases for each PDX tumor/cell line. The WHIM 4 tumor-cell pair showed high level of PIM kinase and EGFR and other PDX tumors such as WHIM18, WHIM 20 (Luminal subtypes), WHIM 35(HER2 enriched subtype) also showed model unique intrinsic kinases, such as JAK2 for WHIM18, EPHB4 for WHIM20.

(Conclusion) PDX tumor-derived ex vivo lines could be routinely cultured with Rock inhibitor support. Each PDX tumor and cell line pair were cluster together in hierarchical clustering and categorized into the same intrinsic subtype based on kinome profiling, suggesting these cells maintain their tumor specific intrinsic kinase signaling. A subset of kinases exhibit activity/expression that is conserved after ex vivo culture, we hypothesize these are intrinsic kinases might be promising target for treatment, because they are tumor intrinsic, i.e. their high expression is maintained despite the strong contrast in the microenvironment of in vitro versus in vitro growth. Ongoing studies with drugs and knock down reagents are examining whether the in vivo/ex vivo comparative KIP analysis indeed identifies therapeutic targets, which will be presented at the meeting more in detail.

Citation Format: Han A, Kim B-J, Chan DW, Matsunuma R, Singh P, Ellis MJ. Proteomic analysis of conserved kinases between PDX tumors and corresponding PDX-derived cell lines [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 P5-06-01.

3D collagen architecture induces a conserved migratory and transcriptional response linked to vasculogenic mimicry

The topographical organization of collagen within the tumor microenvironment has been implicated in modulating cancer cell migration and independently predicts progression to metastasis. Here, we show that collagen matrices with small pores and short fibers, but not Matrigel, trigger a conserved transcriptional response and subsequent motility switch in cancer cells resulting in the formation of multicellular network structures. The response is not mediated by hypoxia, matrix stiffness, or bulk matrix density, but rather by matrix architecture-induced β1-integrin upregulation. The transcriptional module associated with network formation is enriched for migration and vasculogenesis-associated genes that predict survival in patient data across nine distinct tumor types. Evidence of this gene module at the protein level is found in patient tumor slices displaying a vasculogenic mimicry (VM) phenotype. Our findings link a collagen-induced migration program to VM and suggest that this process may be broadly relevant to metastatic progression in solid human cancers.

Extracellular matrix plays a central role in driving cancer development. Here the authors using an in vitro approach show that confining collagen architectures induce fast and persistent cell migration and the formation of multicellular network structures linked to vascular mimicry observed in tumours from patients.

Importance of surgeon-performed ultrasound in the preoperative nodal assessment of patients with potential thyroid malignancy

INTRODUCTION

A comprehensive cervical ultrasound evaluation is essential in the operative planning of patients with thyroid disease. Reliance on radiographic reports alone may result in incomplete operative management as pathologic lymph nodes are often not palpable and evaluation of the lateral neck is not routine. This study examined the role of surgeon-performed ultrasound in the evaluation of patients who underwent lateral neck dissection for thyroid cancer.

METHODS

We conducted a retrospective review of a prospectively maintained database of patients who underwent therapeutic lymph node dissection for thyroid cancer between 2001 and 2016 at our tertiary referral center. All patients had surgeon-performed ultrasound preoperatively by 1 of 7 endocrine surgeons. These findings were compared with prereferral imaging studies to determine the value of surgeon-performed ultrasound to their overall treatment.

RESULTS

Of 92 patients who underwent thyroidectomy with lateral neck dissection, 97% had prereferral imaging of the neck (ultrasonography, computed tomography, positron emission tomography). Of these patients, nodal disease was suggested by computed tomography scanning in 70.8% and by ultrasonography in 54%. Of all patients, 45% had positive lateral neck nodes detected only on surgeon-performed ultrasound despite prior neck imaging. Nodal disease was identified in 50% of patients with only 1 study and 50% of patients with greater than 1 study before surgeon-performed ultrasound. Of patients with nodes detected by surgeon-performed ultrasound, only 67% had a prereferral diagnosis of thyroid cancer.

CONCLUSIONS

Our data demonstrate that reliance on standard preoperative imaging alone would have led to an incorrect initial operation in 45% of our patients. Awareness of the limitations of prereferral imaging is important for surgeons treating patients with thyroid and parathyroid disease. Surgeon-performed ultrasound is a useful tool in the diagnosis and accurate staging of patients.

Comparison of Kaposi Sarcoma Risk in Human Immunodeficiency Virus-Positive Adults Across 5 Continents: A Multiregional Multicohort Study

BACKGROUND

We compared Kaposi sarcoma (KS) risk in adults who started antiretroviral therapy (ART) across the Asia-Pacific, South Africa, Europe, Latin, and North America.

METHODS

We included cohort data of human immunodeficiency virus (HIV)-positive adults who started ART after 1995 within the framework of 2 large collaborations of observational HIV cohorts. We present incidence rates and adjusted hazard ratios (aHRs).

RESULTS

We included 208140 patients from 57 countries. Over a period of 1066572 person-years, 2046 KS cases were diagnosed. KS incidence rates per 100000 person-years were 52 in the Asia-Pacific and ranged between 180 and 280 in the other regions. KS risk was 5 times higher in South African women (aHR, 4.56; 95% confidence intervals [CI], 2.73-7.62) than in their European counterparts, and 2 times higher in South African men (2.21; 1.34-3.63). In Europe, Latin, and North America KS risk was 6 times higher in men who have sex with men (aHR, 5.95; 95% CI, 5.09-6.96) than in women. Comparing patients with current CD4 cell counts ≥700 cells/µL with those whose counts were <50 cells/µL, the KS risk was halved in South Africa (aHR, 0.53; 95% CI, .17-1.63) but reduced by ≥95% in other regions.

CONCLUSIONS

Despite important ART-related declines in KS incidence, men and women in South Africa and men who have sex with men remain at increased KS risk, likely due to high human herpesvirus 8 coinfection rates. Early ART initiation and maintenance of high CD4 cell counts are essential to further reducing KS incidence worldwide, but additional measures might be needed, especially in Southern Africa.

Impedance spectroscopy-based cell/particle position detection in microfluidic systems

An impedance spectroscopy-based cell/particle position detection method in microfluidic systems is presented. A single pair of non-parallel surface microelectrodes was utilized to detect the transverse positions of particles/cells flowing in a microchannel without the need for a multi-electrode multi-channel impedance detection. This method can be a simple solution for high-throughput and low-cost position detection in microfluidic sorting and separation applications.

Involved-field irradiation in definitive chemoradiotherapy for T4 squamous cell carcinoma of the esophagus

OBJECTIVES

Definitive concurrent chemoradiotherapy (ccrt) is currently a therapeutic option for locally advanced esophageal cancer. However, clinical practice differs with respect to the target volume for irradiation. The purpose of the present study was to analyze failure patterns and survival, and to determine the feasibility of using involved-field irradiation (ifi) with concurrent chemotherapy for T4 squamous cell carcinoma (scc) of the esophagus.

METHODS

Between January 2003 and January 2013, 56 patients with clinical T4M0 scc of the esophagus received ccrt using ifi. The radiation field included the primary tumour and clinically involved lymph nodes. Target volumes and sites of failure were analyzed, as were treatment-related toxicity and survival time.

RESULTS

In this 56-patient cohort, 13 patients (23.2%) achieved a complete response, and 21 (37.5%) achieved a partial response, for a total response rate of 60.7%. The major toxicities experienced were leucocytopenia and esophagitis, with 14 patients (25.0%) experiencing grade 3 toxicities. At a median follow-up of 34 months, 48 patients (85.7%) had experienced failure: 39 (69.6%) in-field, 7 (12.5%) elective nodal, and 19 (33.9%) distant. Only 1 patient (1.8%) experienced isolated elective nodal failure. The 1-, 2-, and 3-year survival rates were 39.3%, 21.4%, and 12.5% respectively.

CONCLUSIONS

For patients with T4M0 scc of the esophagus, definitive ccrt using ifi resulted in an acceptable rate of isolated elective nodal failure and an overall survival comparable to that achieved with elective nodal irradiation. A limited radiation therapy target volume, including only clinically involved lesions, would therefore be a feasible choice for this patient subgroup.

Incorporation of Electronic Brachytherapy for Skin Cancer into a Community Dermatology Practice

OBJECTIVE

The introduction of an electronic brachytherapy delivery system into an existing general dermatology practice is described. Radiobiologic rational for the dose fractionation schedule is detailed.

DESIGN

A miniaturized 50keV x-ray tube and delivery system are United States Food and Drug Administration cleared for nonmelanoma skin cancer. The device is introduced into an existing multi-physician dermatology practice in a standard unshielded treatment room.

SETTING

A multi-site, multi-physician dermatology practice Results: Fifteen months following introduction of the system, a total of 524 nonmelanoma skin cancer patients have been treated. At 12.5 months follow-up, there have been four recurrences and cosmesis has been excellent.

CONCLUSIONS

Advances in radiobiology and radiotechnology permit the treatment course to be given in eight fractions over four weeks. Radiation therapy for nonmelanoma skin cancer can now be given in an office setting as an alternative to Mohs surgery for appropriately selected patients. Results are comparable or better than those of surgery. Advances in radiobiology and radiotechnology permit the treatment course to be given in as few as eight fractions over four weeks. Patients are pleased with the convenience of the short course of therapy given in the office.

Biased signalling and proteinase-activated receptors (PARs): targeting inflammatory disease

Although it has been known since the 1960s that trypsin and chymotrypsin can mimic hormone action in tissues, it took until the 1990s to discover that serine proteinases can regulate cells by cleaving and activating a unique four-member family of GPCRs known as proteinase-activated receptors (PARs). PAR activation involves the proteolytic exposure of its N-terminal receptor sequence that folds back to function as a 'tethered' receptor-activating ligand (TL). A key N-terminal arginine in each of PARs 1 to 4 has been singled out as a target for cleavage by thrombin (PARs 1, 3 and 4), trypsin (PARs 2 and 4) or other proteases to unmask the TL that activates signalling via Gq , Gi or G12 /13 . Similarly, synthetic receptor-activating peptides, corresponding to the exposed 'TL sequences' (e.g. SFLLRN-, for PAR1 or SLIGRL- for PAR2) can, like proteinase activation, also drive signalling via Gq , Gi and G12 /13 , without requiring receptor cleavage. Recent data show, however, that distinct proteinase-revealed 'non-canonical' PAR tethered-ligand sequences and PAR-activating agonist and antagonist peptide analogues can induce 'biased' PAR signalling, for example, via G12 /13 -MAPKinase instead of Gq -calcium. This overview summarizes implications of this 'biased' signalling by PAR agonists and antagonists for the recognized roles the PARs play in inflammatory settings.

Pathway-selective antagonism of proteinase activated receptor 2

BACKGROUND AND PURPOSE

Proteinase activated receptor 2 (PAR2) is a GPCR associated with inflammation, metabolism and disease. Clues to understanding how to block PAR2 signalling associated with disease without inhibiting PAR2 activation in normal physiology could be provided by studies of biased signalling.

EXPERIMENTAL APPROACH

PAR2 ligand GB88 was profiled for PAR2 agonist and antagonist properties by several functional assays associated with intracellular G-protein-coupled signalling in vitro in three cell types and with PAR2-induced rat paw oedema in vivo.

KEY RESULTS

In HT29 cells, GB88 was a PAR2 antagonist in terms of Ca(2+) mobilization and PKC phosphorylation, but a PAR2 agonist in attenuating forskolin-induced cAMP accumulation, increasing ERK1/2 phosphorylation, RhoA activation, myosin phosphatase phosphorylation and actin filament rearrangement. In CHO-hPAR2 cells, GB88 inhibited Ca(2+) release, but activated G(i/o) and increased ERK1/2 phosphorylation. In human kidney tubule cells, GB88 inhibited cytokine secretion (IL6, IL8, GM-CSF, TNF-α) mediated by PAR2. A rat paw oedema induced by PAR2 agonists was also inhibited by orally administered GB88 and compared with effects of locally administered inhibitors of G-protein coupled pathways.

CONCLUSIONS AND IMPLICATIONS

GB88 is a biased antagonist of PAR2 that selectively inhibits PAR2/G(q/11)/Ca(2+)/PKC signalling, leading to anti-inflammatory activity in vivo, while being an agonist in activating three other PAR2-activated pathways (cAMP, ERK, Rho) in human cells. These findings highlight opportunities to design drugs to block specific PAR2-linked signalling pathways in disease, without blocking beneficial PAR2 signalling in normal physiology, and to dissect PAR2-associated mechanisms of disease in vivo.

Abstract P6-06-25: Usefulness of pretreatment NLR as prognostic factor of late recurrence, 5-year after primary treatment

Background

Prognostic factor and predictive factors are well established in early-stage breast cancer, but less is known about recurrence, especially 5-year after primary treatment. While mortality of breast cancer is from organic dysfunction with metastatic disease, not from the diseased breast itself, still we do not have adequate information about metastatic disease as we do about primary breast cancer itself.

The aim of this study is to investigate of usefulness of pretreatment NLR(neutrophil to lymphocyte ratio) as prognostic factor that can tell risk of recurrence 5- year after primary treatment.

Patients and methods

A retrospective review of invasive breast cancer patients surgically resected between January 2001 and December 2007. Exclusion criteria were as followings: patients with recurrence or death within 5yrs.

Results

A total of 301 patients were included and 13 patients experienced with recurrence after 5 years.

Table 1. Patients' characteristics Total (n = 301) N (%)Age*48.8(±11.4)Age ≤3525(8.3)35&lt; ≤50165(54.8)50&lt;111(36.9)Histology Ductal270(89.7)Lobular7(2.3)Others24(8.0)Tumor size (cm)*2.73(±1.64)T stage T1126(41.9)T2158(52.5)T317(5.6)N stage N0199(66.1)N167(22.3)N220(6.6)N311(3.7)unknown4(1.3)Histologic grade I72(23.9)II110(36.5)III70 (23.3)unknown49(16.3)Estrogen receptor Negative111(36.9)Positive185(61.5)unknown5(1.6)Progesterone receptor Negative129(42.9)Positive167(55.5)Unknown5(1.6)HER-2 Negative196(65.1)Positive98(32.6)unknown7(2.3)Molecular subtype Luminal A136(45.2)Luminal B66(21.9)HER-2 enriched32(10.6)Triple negative60(20.0)unknown7(2.3)Late recur Yes13(4.3)No288(95.7)*mean±SD

Overall average of NLR value was 2.16, median value was 1.83. The average NLR were 2.80±1.68 in patients with recurrences occurred after 5 years and 2.13±1.15 in patients without recurrence. The NLR cutoff value of 1.83 was determined by median value.

In 1.83≤NLR group has a higher incidence of recurrence after 5 years compared with NLR&lt;1.83 group (8yr DFS 99.2% vs. 93.3%, p = 0.021). Especially in luminal A(ER (+) or PR (+), HER-2(-)), 1.83≤NLR group has a higher incidence of recurrence after 5 years compared with NLR&lt;1.83 group (8yr DFS 100% vs. 87.0%, p = 0.015).

Conclusion

We found that pretreatment NLR is associated with late recurrence that occurs after five years. And we suggest that NLR could be used as one of the prognostic factor that can tell about late recurrence, 5-year after primary treatment.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-25.