First-line osimertinib for patients with EGFR-mutated advanced non-small cell lung cancer: efficacy and safety during the COVID-19 pandemic.

Background: The FLAURA trial demonstrated improved overall survival (OS) with first-line osimertinib for patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer (NSCLC). We studied the efficacy and safety of osimertinib in a cohort treated during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Patients diagnosed with EGFR-mutated advanced NSCLC between 11 March 2020 to 31 December 2021 who received first-line osimertinib in British Columbia, Canada were identified retrospectively. Kaplan-Meier curves of OS and progression-free survival (PFS) from the start of osimertinib were plotted. The associations of baseline characteristics with PFS, and development of pneumonitis or dose reductions due to toxicity with OS were evaluated with hazard ratios estimated using univariable and multivariable Cox models. Results: The cohort comprised 231 individuals. 58.7% of patients with de novo advanced NSCLC were initially diagnosed after presentation to the Emergency Room. At osimertinib initiation, 31.6% were aged ≥75 years and 45.5% had an Eastern Cooperative Oncology Group performance status (ECOG PS) ≥2. Median PFS and OS were 18.0 months [95% confidence interval (CI): 16.1-26.2] and 25.4 months (95% CI: 20.3-not reached), respectively. On multivariable analysis, age ≥75 years (vs. <75), ECOG PS 2/3 (vs. 0/1), ECOG PS 4 (vs. 0/1), current smokers (vs. never smokers), programmed death ligand 1 (PD-L1) expression ≥50% (vs. <1%), and L858R mutation (vs. exon 19 deletion) were associated with shorter PFS. Among 110 patients who progressed, 33.6% received subsequent therapy. A proportion of 16.5% of the cohort developed grade ≥3 adverse events. Pneumonitis from osimertinib (3.9% incidence) was weakly associated with shorter OS (hazard ratio: 2.59, 95% CI: 0.94-7.12, P=0.066); dose reductions were not associated with worse OS. 10.8% of patients developed COVID-19. Conclusions: In a cohort receiving first-line osimertinib during the COVID-19 pandemic, ECOG PS ≥2 was observed in nearly half of patients at treatment initiation contributing to a median OS shorter than in FLAURA. The incidence of severe adverse events was low and dose reduction for drug toxicity did not impact OS. Identifying and reducing barriers to the diagnosis of NSCLC during the COVID-19 pandemic are required.

Metastatic Small Bowel Adenocarcinoma Mimicking a Primary Ovarian Mucinous Tumour - Clinical, Radiologic, Pathologic and Molecular Correlation.

We describe an interesting case of a patient who presented with a large adnexal mass, first favored to be mucinous carcinoma of the gynecologic origin. The primary tumour site was ascertained after the patient's small bowel was resected by identifying an adenomatous component evolving into an invasive adenocarcinoma identical in morphology and immunophenotype to the ovarian tumour. Notably, both tumours were found to harbor a BRAF K601E mutation, which is extremely rare for a primary of the ovary. BRAF mutations are present in a subset of large bowel and small bowel adenocarcinoma, but our case shows the first instance of a BRAF K601E mutation being present in a small bowel adenocarcinoma, to the best of our knowledge. This case serves as a great illustration of the pivotal role of molecular diagnostics in modern pathology in arriving at the correct diagnosis. Additionally, it is an excellent example of how clinical-radiologic-pathologic-molecular correlation plays into the landscape of molecular pathology to deliver optimal care for the patient.

Safety and efficacy of pembrolizumab for advanced nonsmall cell lung cancer: before and during the COVID-19 pandemic.

PURPOSE: The COVID-19 pandemic changed diagnostic and treatment pathways in oncology. We compared the safety and efficacy of pembrolizumab amongst advanced nonsmall cell lung cancer (NSCLC) patients with a PD-L1 tumor proportion score (TPS) ≥ 50% before and during the pandemic. METHODS: Advanced NSCLC patients initiating pembrolizumab between June 2015 and December 2019 ("pre-pandemic cohort") and between March 2020 and March 2021 ("pandemic cohort") at BC Cancer were identified retrospectively. Multivariable logistic regression evaluated risk factors for immune-related adverse events (irAE) ≥ grade 3 at the 6 week, 3 month, and 6 month landmarks. Cox regression models of overall survival (OS) were constructed. RESULTS: The study population comprised 417 patients in the pre-pandemic cohort and 111 patients in the pandemic cohort. Between March and May 2020, 48% fewer advanced NSCLC cases with PD-L1 TPS ≥ 50% were diagnosed compared to similar intervals in 2018-2019. Telemedicine assessment [new patient consultations (p < 0.001) and follow-up (p < 0.001)] and extended interval pembrolizumab dosing (p < 0.001) were more common in the pandemic cohort. Patients initiating pembrolizumab after February 2020 (vs. before January 2020) experienced similar odds of developing severe irAE. 2/111 (1.8%) patients receiving pembrolizumab during the pandemic tested positive for COVID-19. On multivariable analysis, no association between pembrolizumab treatment period (before vs. during the COVID-19 pandemic) and OS was observed (p = 0.18). CONCLUSION: Significant changes in healthcare delivery in response to the pandemic did not result in increased high grade toxicity or lower survival outcomes in patients with advanced NSCLC treated with pembrolizumab.

Improving Time-to-Treatment for Advanced Non-Small Cell Lung Cancer Patients through Faster Single Gene EGFR Testing Using the Idylla™ EGFR Testing Platform.

INTRODUCTION: Patients with advanced-stage non-small cell lung cancer (NSCLC) may benefit from a short time-to-treatment (TTT). Predictive biomarker testing is performed prior to treatment, as recommended by various international expert consensus bodies. Genetic testing is more time-intensive than immunohistochemistry (IHC) and commonly contributes to prolonged TTT. For epidermal growth factor receptor-positive patients (EGFR+), further genetic testing may not be required due to the mutual exclusivity of actionable mutations. METHODS: The trial cohort (N = 238) received both BC Cancer NGS panel (Oncopanel) and Idylla EGFR testing. Data were also collected for a control cohort (N = 220) that received Oncopanel testing. For each patient, the time that the lab received the sample, the time taken to report the NGS and Idylla tests, the time of first treatment, and the final treatment regimen were recorded. RESULTS: A concordance frequency of 98.7% (232/235) was observed between the Idylla and NGS panel. The lab turnaround time (TAT) was faster for the Idylla test by an average of 12.4 days (N = 235, p < 0.01). Overall, the average TTT in the trial cohort (N = 114) was 10.1 days faster (p < 0.05) than the control (N = 114), leading to a 25% reduction in TTT. For patients treated based on EGFR positivity, the mean TTT was 16.8 days faster (p < 0.05) in the trial cohort (N = 33) than the control cohort (N = 28), leading to a 48% reduction in TTT. CONCLUSION: Using the Idylla EGFR test as part of the molecular testing repertoire in advanced-stage NSCLC patients could significantly reduce TTT.

Endometrial neuroendocrine carcinoma and undifferentiated carcinoma are distinct entities with overlap in neuroendocrine marker expression.

AIMS: Dedifferentiated endometrial carcinomas (DDECs)/undifferentiated endometrial carcinomas (UDECs) frequently harbour genomic activation of switch/sucrose non-fermentable (SWI/SNF)-complex proteins, and can show histological overlap with neuroendocrine carcinoma (NEC). The aim of this study was to compare the extent of the expression of neuroendocrine markers, SWI/SNF proteins and mismatch repair (MMR) proteins in DDEC/UDEC and NEC. METHODS AND RESULTS: The extent of expression of synaptophysin, chromogranin, CD56, ARID1A, ARID1B, SMARCA4, SMARCB1 and MMR proteins was evaluated by immunohistochemistry on 44 SWI/SNF-deficient DDECs/UDECs and 15 NECs. Thirty-three of 44 (75%) DDECs/UDECs showed expression of at least one neuroendocrine marker, with 18 of 44 (41%) expressing two or more neuroendocrine markers, whereas all 15 NECs showed expression of at least one neuroendocrine marker, with 14 of 15 (93%) expressing two or more neuroendocrine markers. Neuroendocrine marker expression in DDECs/UDECs was typically focal when present, with average extents of 17%, 4% and 8% for synaptophysin, chromogranin and CD56 in the positive cases, respectively, in contrast to 73%, 40% and 62% in the positive NEC cases, respectively. All 15 NECs showed intact expression of SWI/SNF-complex proteins, except for one that showed isolated loss of ARID1A. Thirty-eight of 44 DDECs/UDECs were MMR-abnormal (34 with loss of MLH1 and PMS2, and four with loss of PMS2 alone), whereas all NECs retained MMR protein expression. CONCLUSIONS: Our study demonstrates frequent but typically focal neuroendocrine marker expression in SWI/SNF-deficient DDECs/UDECs, whereas NECs typically express two or more neuroendocrine markers, with diffuse expression of at least one marker. ARID1B, SMARCA4 and SMARCB1 immunohistochemistry can be used to aid in the differentiation between DDEC/UDEC and NEC.

Radiation Induced Abscopal Effect in a Patient With Malignant Pleural Mesothelioma on Pembrolizumab.

Abscopal effect is a rare phenomenon in which treatment benefit from radiotherapy (RT) is seen outside the target field due to activation of the immune system inducing an anti-tumor effect. This phenomenon has been reported in cancer patients receiving immune checkpoint inhibitors (ICI). Here we report a case of presumed abscopal effect in malignant mesothelioma. The patient received second-line single-agent pembrolizumab however had disease progression after four cycles leading to palliative RT (20 Gray) to the right mainstem bronchus. Follow-up radiographic imaging confirmed benefit and pembrolizumab was continued. Follow-up computed tomography (CT) five months after RT, showed marked radiographic improvement of all measurable diseases with improvement in right-sided aerated lung volume. Because of the original disease progression on pembrolizumab, with marked improvements within and outside the RT field after RT, treatment response was presumed due to the abscopal effect.

CAP-ACP Workload Model for Advanced Diagnostics in Precision Medicine.

OBJECTIVES: In precision medicine, where oncologic management is tailored to the individual's clinical and genetic profiles, advanced diagnostic testing provides prognostic information and guides management in a growing number of malignancies. There is a need to capture the work pathologists perform to meet this demand by providing medically relevant, timely, and accurate testing results. This work includes not only direct patient consults (interpretation of results and issuing reports) but the administrative and medical oversight as well as the research needed to provide the necessary quality assurance, quality control, direction, and framework for the laboratory. METHODS: An expert panel of Canadian pathologists involved in advanced diagnostics was convened to establish and beta test a model for workload assessment in advanced diagnostics. RESULTS: All aspects of the advanced diagnostics workload were detailed and applied to models based on members' experience, including medical oversight, administration, and the introduction of new testing and platforms. Models for biomarker testing were developed for simple and complex or multiplexed assays, and a detailed model was developed to assess the workload for next-generation sequencing-based assays. CONCLUSIONS: This paper provides the first detailed proposal for capturing an advanced diagnostic workload to enable appropriate pathologist allotment for performing all the steps required to run an advanced diagnostic service.

MET exon 14 skipping mutation positive non-small cell lung cancer: Response to systemic therapy.

OBJECTIVES: MET exon 14 skipping is a potentially targetable molecular alteration. The goals of this study were to identify patients treated in British Columbia with MET exon 14 skipping to understand prevalence, biology and response to treatment, and to identify molecular signatures that may predict for response or resistance to targeted MET therapy in the setting of advanced disease. MATERIALS AND METHODS: A retrospective review was completed of patients found to have MET exon 14 skipping alterations between January 2016-September 2019. Information was collected on baseline characteristics, response to systemic treatments, and outcomes. RESULTS: Out of 1934 advanced, non-squamous and never-smoking squamous NSCLC patients tested, 41 patients were found to have MET exon 14 skipping (2.1 %). MET alteration types: 2% CBL binding-domain mutations, 34 % poly-pyrimidine tract deletions, 63 % splice donor mutations or deletions. The most common co-mutation was TP53 (22 %). Thirty-three patients received systemic therapy. Physician-assessed disease control was 68 % among 19 evaluable patients treated with crizotinib, 80 % among 10 evaluable patients treated with platinum-based chemotherapy, and 70 % among 10 evaluable patients treated with immunotherapy. Median time to treatment discontinuation was 3.0, 2.8, and 2.4 months, respectively. Median overall survival for metastatic patients treated with any systemic therapy was 15.4 months. In this small cohort, there were no clear correlations between molecular aberrations and response, time to treatment discontinuation, or survival for crizotinib, chemotherapy, and immunotherapy. CONCLUSION: The prevalence of MET exon 14 skipping in a North American population was 2.1 %. Unlike other targetable mutations, patients were older and more commonly current or former smokers. Patients with MET exon 14 skipping alteration demonstrate disease control with crizotinib, platinum-based chemotherapy and immunotherapy. Co-mutations with TP53 were commonly noted, but correlation between co-mutations and efficacy of therapy were not identified in this cohort.

Prognostic significance of the neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio for advanced non-small cell lung cancer patients with high PD-L1 tumor expression receiving pembrolizumab.

BACKGROUND: We investigated the association of peripheral blood inflammatory markers with overall survival (OS) in pembrolizumab treated advanced non-small cell lung cancer (aNSCLC) patients with programmed death ligand 1 (PD-L1) expression ≥50%. Clinical risk factors for development of immune-related adverse events (irAE) were also explored. METHODS: aNSCLC patients with high PD-L1 expression receiving pembrolizumab monotherapy outside of clinical trials were identified retrospectively. All patients were treated at one of six British Columbia Cancer clinics between August 2017 and June 2019. Patients were dichotomized using baseline neutrophil-to-lymphocyte ratio (NLR,

MET Exon 14-altered Lung Cancers and MET Inhibitor Resistance.

PURPOSE: MET tyrosine kinase inhibitors (TKIs) can achieve modest clinical outcomes in MET exon 14-altered lung cancers, likely secondary to primary resistance. Mechanisms of primary resistance remain poorly characterized and comprehensive proteomic analyses have not previously been performed. EXPERIMENTAL DESIGN: We performed hybrid capture-based DNA sequencing, targeted RNA sequencing, cell-free DNA sequencing, selected reaction monitoring mass spectrometry (SRM-MS), and immunohistochemistry on patient samples of MET exon 14-altered lung cancers treated with a MET TKI. Associations between overall response rate (ORR), progression-free survival (PFS), and putative genomic alterations and MET protein expression were evaluated. RESULTS: Seventy-five of 168 MET exon 14-altered lung cancers received a MET TKI. Previously undescribed (zygosity, clonality, whole-genome duplication) and known (copy-number focality, tumor mutational burden, mutation region/type) genomic factors were not associated with ORR/PFS (P > 0.05). In contrast, MET expression was associated with MET TKI benefit. Only cases with detectable MET expression by SRM-MS (N = 15) or immunochemistry (N = 22) responded to MET TKI therapy, and cancers with H-score ≥ 200 had a higher PFS than cancers below this cutoff (10.4 vs. 5.5 months, respectively; HR, 3.87; P = 0.02). CONCLUSIONS: In MET exon 14-altered cancers treated with a MET TKI, a comprehensive analysis of previously unknown and known genomic factors did not identify a genomic mechanism of primary resistance. Instead, MET expression correlated with benefit, suggesting the potential role of interrogating the proteome in addition to the genome in confirmatory prospective trials.

Results from the 2019 American Society of Cytopathology survey on rapid onsite evaluation (ROSE)-part 2: subjective views among the cytopathology community.

INTRODUCTION: This study aims to improve understanding of the cytopathology community's perspective regarding the value of rapid onsite evaluation (ROSE) in clinical practice. MATERIALS AND METHODS: The American Society of Cytopathology membership was surveyed in 2019 to obtain subjective data on the cytopathology community's perceptions regarding ROSE. Comments were categorized by major themes and attitudes and analyzed by respondent's role in laboratory, practice size, and practice setting (Fisher's exact and χ2 tests). RESULTS: A total of 541 responses were received from 255 cytopathologists/pathologists, 261 cytotechnologists, 19 trainees, and 6 others (as previously reported). Reasons for which cytopathology personnel provide this service aligned with their perceptions of why clinicians request ROSE. A minority of respondents, disproportionally from high volume centers, felt ROSE is unnecessary. Overall attitude regarding ROSE was generally positive. There were no significant differences in attitude regarding ROSE according to role in laboratory or practice size, but respondents from academic centers provided a significantly higher percentage of positive comments than those in private or community practice. Although survey respondents generally felt that ROSE is valuable to patient care, they also highlighted several challenges, including staffing, time commitment, and inadequate reimbursement. Implementation of telecytology was felt to potentially alleviate some of these challenges. CONCLUSIONS: Survey results show that the cytology community views ROSE favorably, practices vary considerably, and there is a perceived need for improved reimbursement. Data from this study may be used to identify areas that warrant additional research to clarify the clinical value of ROSE.

Pan-Trk immunohistochemistry is a sensitive and specific ancillary tool for diagnosing secretory carcinoma of the salivary gland and detecting ETV6-NTRK3 fusion.

AIMS: Secretory carcinoma (SC) of the salivary gland typically harbours ETV6-NTRK3 fusion, which can be utilised clinically to assist with diagnosis. Pan-Trk inhibitor therapy has demonstrated drastic responses in patients with NTRK-translocated tumours, including SC. Pan-Trk immunohistochemistry (IHC) is emerging as a sensitive and specific tool for detecting NTRK1, NTRK2 and NTRK3 fusions in various cancers. We aimed to establish the specificity and sensitivity of pan-Trk IHC in diagnosing SC and detecting ETV6-NTRK3 fusion. A literature review on the utility of pan-Trk IHC was conducted. METHODS AND RESULTS: Pan-Trk IHC was performed on 83 salivary gland neoplasms (29 SCs and 54 non-SCs). ETV6-NTRK3 fusion status was established in 25 cases. With any staining (nuclear or cytoplasmic) as a positive threshold, the sensitivity and specificity of pan-Trk IHC were 90% and 70% in diagnosing SC, and 100% and 0% in detecting NTRK3 fusion. When only pan-Trk nuclear staining was considered as positive, the sensitivity and specificity were 69% and 100% in diagnosing SC, and 92% and 100% in detecting NTRK3 fusion. CONCLUSIONS: Nuclear pan-Trk IHC is highly specific for SC diagnosis, with a specificity approaching 100%, making it a useful and precise diagnostic tool for differentiating SC from its histological mimics. On the other hand, any pan-Trk staining (nuclear or cytoplasmic) is highly sensitive for SC, and can serve as an attractive, cheap, fast and accessible screening tool for selecting patients to undergo confirmative molecular testing for clinical trials using TRK inhibitors.

#EBUSTwitter: Novel Use of Social Media for Conception, Coordination, and Completion of an International, Multicenter Pathology Study.

CONTEXT.­: Social media sites are increasingly used for education, networking, and rapid dissemination of medical information, but their utility for facilitating research has remained largely untapped. OBJECTIVE.­: To describe in detail our experience using a social media platform (Twitter) for the successful initiation, coordination, and completion of an international, multi-institution pathology research study. DESIGN.­: Following a tweet describing a hitherto-unreported biopsy-related histologic finding in a mediastinal lymph node following endobronchial ultrasound-guided transbronchial needle aspiration, a tweet was posted to invite pathologists to participate in a validation study. Twitter's direct messaging feature was used to create a group to facilitate communication among participating pathologists. Contributing pathologists reviewed consecutive cases of mediastinal lymph node resection following endobronchial ultrasound-guided transbronchial needle aspiration and examined them specifically for biopsy site changes. Data spreadsheets containing deidentified data and digital photomicrographs of suspected biopsy site changes were submitted via an online file hosting service for central review by 5 pathologists from different institutions. RESULTS.­: A total of 24 pathologists from 14 institutions in 5 countries participated in the study within 143 days of study conception, and a total of 297 cases were collected and analyzed. The time interval between study conception and acceptance of the manuscript for publication was 346 days. CONCLUSIONS.­: To our knowledge, this is the first time that a social media platform has been used to generate a research idea based on a tweet, recruit coinvestigators publicly, communicate with collaborating pathologists, and successfully complete a pathology study.

SMARCA4-Deficient Thoracic Sarcomatoid Tumors Represent Primarily Smoking-Related Undifferentiated Carcinomas Rather Than Primary Thoracic Sarcomas.

INTRODUCTION: Highly aggressive thoracic neoplasms characterized by SMARCA4 (BRG1) deficiency and undifferentiated round cell or rhabdoid morphology have been recently described and proposed to represent thoracic sarcomas. However, it remains unclear whether such tumors may instead represent sarcomatoid carcinomas, and how their clinicopathologic characteristics compare with those of nonsarcomatoid SMARCA4-deficient non-small cell lung carcinomas (SD-NSCC). METHODS: We identified 22 SMARCA4-deficient thoracic sarcomatoid tumors (SD-TSTs) with round cell and/or rhabdoid morphology and 45 SD-NSCCs, and comprehensively analyzed their clinicopathologic, immunohistochemical, and genomic characteristics using 341-468 gene next-generation sequencing and other molecular platforms. RESULTS: The relationship of SD-TSTs with NSCC was supported by (1) the presence of NSCC components juxtaposed with sarcomatoid areas in five cases, (2) focal expression of NSCC lineage markers TTF1 or p40 in four additional cases, (3) smoking history in all except one patient (mean = 51 pack-years), accompanied by genomic smoking signature, and (4) high tumor mutation burden (mean = 14.2 mutations per megabase) and mutations characteristic of NSCC in a subset. Compared with SD-NSCCs, SD-TSTs exhibited considerably larger primary tumor size (p < 0.0001), worse survival (p = 0.004), and more frequent presentation at younger age (30-50 years) despite heavier smoking history. Distinctive pathologic features of SD-TSTs included consistent lack of adhesion molecule claudin-4, SMARCA2 (BRM) codeficiency, and frequent expression of stem cell markers. CONCLUSIONS: SD-TSTs represent primarily smoking-associated undifferentiated/de-differentiated carcinomas rather than primary thoracic sarcomas. Despite their histogenetic relationship with NSCC, these tumors have unique clinicopathologic characteristics, supporting their recognition as a distinct entity. Further studies are warranted to determine therapeutic approaches to this novel class of exceptionally aggressive thoracic tumors.

RUNX2 (6p21.1) amplification in osteosarcoma.

Prior cytogenetic profiling of osteosarcomas has suggested that amplifications at the 6p12-21 locus are relatively common alterations in these tumors. However, these studies have been limited by variable testing methodologies used as well as by the relatively small numbers of cases that have been analyzed. To better define the frequency of this alteration, 111 osteosarcomas were profiled using hybridization capture-based next-generation sequencing (NGS) platform (Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets) as part of an institutional clinical cancer genomics initiative. Using this platform, amplification at the 6p12-21 locus was determined by copy number assessment of the VEGFA and CCND3 genes. In addition, fluorescence in situ hybridization was used to assess copy number status for RUNX2, a known transcriptional regulator of osteoblastic differentiation which has previously been reported to be dysregulated in osteosarcomas. 6p12-21 amplification using NGS-based copy number assessment was confirmed in more than a fifth of all cases tested (24 of 111, 21.6%). Most of these cases, when tested using fluorescence in situ hybridization, were found to include RUNX2 within the amplified locus (17 of 18, 94.4%). Whereas many laboratories lack access to large-panel NGS assays, the use of fluorescence in situ hybridization to identify 6p12-21 amplification events by targeting RUNX2 represents a widely available diagnostic modality for the identification of such cases. This could help better define the role of RUNX2 in osteoblastic differentiation and serve as a surrogate for the identification of potentially targetable alterations such as VEGFA amplification at this locus.

Results from the 2019 American Society of Cytopathology survey on rapid on-site evaluation-Part 1: objective practice patterns.

INTRODUCTION: Rapid on-site evaluation (ROSE) is a service provided by cytologists that helps ensure specimen adequacy and appropriate triage for ancillary testing. However, data on the current usage patterns across different practice settings have been lacking. MATERIALS AND METHODS: To obtain an accurate and timely assessment of the current state of practice of ROSE, a 14-question online survey was constructed by the Clinical Practice Committee of the American Society for Cytopathology. The survey was available to the membership of the American Society for Cytopathology for a 3-week period in early 2019. RESULTS: A total of 541 responses were received, including from 255 cytopathologists/pathologists, 261 cytotechnologists, 19 cytology resident/fellow trainees, and 6 others. ROSE was offered as a clinical service by 95.4% of the respondents, with telecytology for ROSE used in 21.9% of the practices. Endobronchial ultrasound-guided transbronchial needle aspiration was the procedure most frequently reported to use ROSE (mean, 59.1%; median, 70%). Cytotechnologists were involved in ROSE in most practices. The number of daily ROSE procedures correlated with the annual nongynecologic cytology volumes. Approximately 70% of ROSE procedures were reported to require >30 minutes, on average, for the cytologist. CONCLUSIONS: The results from our survey of cytologists have shown that the reported practice patterns for the usage of ROSE vary considerably. The presented data can help inform future guideline recommendations and the implementation of ROSE in different clinical settings.

Comprehensive Next-Generation Sequencing Unambiguously Distinguishes Separate Primary Lung Carcinomas From Intrapulmonary Metastases: Comparison with Standard Histopathologic Approach.

PURPOSE: In patients with >1 non-small cell lung carcinoma (NSCLC), the distinction between separate primary lung carcinomas (SPLCs) and intrapulmonary metastases (IPMs) is a common diagnostic dilemma with critical staging implications. Here, we compared the performance of comprehensive next-generation sequencing (NGS) with standard histopathologic approaches for distinguishing NSCLC clonal relationships in clinical practice. EXPERIMENTAL DESIGN: We queried 4,119 NSCLCs analyzed by 341-468 gene MSK-IMPACT NGS assay for patients with >1 surgically resected tumor profiled by NGS. Tumor relatedness predicted by prospective histopathologic assessment was contrasted with comparative genomic profiling by subsequent NGS. RESULTS: Sixty patients with NGS performed on >1 NSCLCs were identified, yielding 76 tumor pairs. NGS classified tumor pairs into 51 definite SPLCs (median, 14; up to 72 unique somatic mutations per pair), and 25 IPMs (24 definite, one high probability; median, 5; up to 16 shared somatic mutations per pair). Prospective histologic prediction was discordant with NGS in 17 cases (22%), particularly in the prediction of IPMs (44% discordant). Retrospective review highlighted several histologic challenges, including morphologic progression in some IPMs. We subsampled MSK-IMPACT data to model the performance of less comprehensive assays, and identified several clinicopathologic differences between NGS-defined tumor pairs, including increased risk of subsequent recurrence for IPMs. CONCLUSIONS: Comprehensive NGS allows unambiguous delineation of clonal relationship among NSCLCs. In comparison, standard histopathologic approach is adequate in most cases, but has notable limitations in the recognition of IPMs. Our results support the adoption of broad panel NGS to supplement histology for robust discrimination of NSCLC clonal relationships in clinical practice.

Clinical Genomic Sequencing of Pediatric and Adult Osteosarcoma Reveals Distinct Molecular Subsets with Potentially Targetable Alterations.

PURPOSE: Although multimodal chemotherapy has improved outcomes for patients with osteosarcoma, the prognosis for patients who present with metastatic and/or recurrent disease remains poor. In this study, we sought to define how often clinical genomic sequencing of osteosarcoma samples could identify potentially actionable alterations.Experimental Design: We analyzed genomic data from 71 osteosarcoma samples from 66 pediatric and adult patients sequenced using MSK-IMPACT, a hybridization capture-based large panel next-generation sequencing assay. Potentially actionable genetic events were categorized according to the OncoKB precision oncology knowledge base, of which levels 1 to 3 were considered clinically actionable. RESULTS: We found at least one potentially actionable alteration in 14 of 66 patients (21%), including amplification of CDK4 (n = 9, 14%: level 2B) and/or MDM2 (n = 9, 14%: level 3B), and somatic truncating mutations/deletions in BRCA2 (n = 3, 5%: level 2B) and PTCH1 (n = 1, level 3B). In addition, we observed mutually exclusive patterns of alterations suggesting distinct biological subsets defined by gains at 4q12 and 6p12-21. Specifically, potentially targetable gene amplifications at 4q12 involving KIT, KDR, and PDGFRA were identified in 13 of 66 patients (20%), which showed strong PDGFRA expression by IHC. In another largely nonoverlapping subset of 14 patients (24%) with gains at 6p12-21, VEGFA amplification was identified. CONCLUSIONS: We found potentially clinically actionable alterations in approximately 21% of patients with osteosarcoma. In addition, at least 40% of patients have tumors harboring PDGFRA or VEGFA amplification, representing candidate subsets for clinical evaluation of additional therapeutic options. We propose a new genomically based algorithm for directing patients with osteosarcoma to clinical trial options.

Displaced Cartilage Within Lymph Node Parenchyma Is a Novel Biopsy Site Change in Resected Mediastinal Lymph Nodes Following EBUS-TBNA.

Biopsy site changes in mediastinal lymph nodes (LNs) attributable to prior endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) have not been studied in a systematic manner. Twenty-four contributors from 14 institutions in 5 countries collaborated via social media (Twitter) to retrospectively review consecutive cases of resected mediastinal LNs from patients with prior EBUS-TBNA. Resected LNs were reexamined by submitting pathologists for changes attributable to EBUS-TBNA. Patients who received neoadjuvant therapy were excluded. Cases with suspected biopsy site changes underwent central review by 5 pathologists. A total of 297 mediastinal LN resection specimens from 297 patients (183 male/114 female, mean age: 65 y, range: 23 to 87) were reviewed. Biopsy site changes were most common in station 7 (10 cases) followed by 11R, 4R, and 10R, and were found in 34/297 (11.4%) cases, including displacement of tiny cartilage fragments into LN parenchyma in 26, intranodal or perinodal scars in 7, and hemosiderin in 1. Cartilage fragments ranged from 0.26 to 1.03 mm in length and 0.18 to 0.62 mm in width. The mean interval between EBUS-TBNA and LN resection was 38 days (range: 10 to 112) in cases with biopsy site changes. A control group of 40 cases without prior EBUS-TBNA, including 193 mediastinal LN stations, showed no evidence of biopsy site changes. Biopsy site changes are identified in a subset of resected mediastinal LNs previously sampled by EBUS-TBNA. The location of the abnormalities, temporal association with prior EBUS-TBNA, and the absence of such findings in cases without prior EBUS-TBNA support the contention that they are caused by EBUS-TBNA.

Solitary fibrous tumor with neuroendocrine and squamous dedifferentiation: a potential diagnostic pitfall.

Solitary fibrous tumor (SFT) is a ubiquitous mesenchymal neoplasm of deep soft tissue with variable and often unpredictable biological behavior. The lineage is presumed to be fibroblastic, and histological features range from benign to overtly malignant with rare tumors showing "dedifferentiation" or transformation to undifferentiated pleomorphic sarcoma. Dedifferentiation in mesenchymal neoplasms is a phenomenon of histologic progression of a well-differentiated neoplasm to a high-grade sarcoma, which can differentiate along divergent lines. It is extremely uncommon to encounter "transdifferentiation" to non-mesenchymal lineage and still maintaining the driver genetic event of the primary tumor. Herein, we report two diagnostically challenging SFTs with transformation to neuroendocrine and squamous phenotypes. The index case is a pelvic malignant SFT, which metastasized to the liver as a high-grade neuroendocrine carcinoma. The second case is a recurrent brain tumor initially presenting as a typical SFT and evolving into a dedifferentiated SFT with foci of squamous differentiation. Positive immunohistochemical stains for CD34 and STAT6 and the detection of NAB2-STAT6 fusion supported the diagnosis of dedifferentiated SFT in both cases. In the first case, molecular study also demonstrated that both the pelvic primary and liver metastasis harbored the same NAB2-STAT6 fusion. Dedifferentiation to a non-mesenchymal lineage/lineage infidelity can be a potential diagnostic pitfall in these tumors.