Pan-cancer whole-genome analyses of metastatic solid tumours.

Metastatic cancer is a major cause of death and is associated with poor treatment efficacy. A better understanding of the characteristics of late-stage cancer is required to help adapt personalized treatments, reduce overtreatment and improve outcomes. Here we describe the largest, to our knowledge, pan-cancer study of metastatic solid tumour genomes, including whole-genome sequencing data for 2,520 pairs of tumour and normal tissue, analysed at median depths of 106× and 38×, respectively, and surveying more than 70 million somatic variants. The characteristic mutations of metastatic lesions varied widely, with mutations that reflect those of the primary tumour types, and with high rates of whole-genome duplication events (56%). Individual metastatic lesions were relatively homogeneous, with the vast majority (96%) of driver mutations being clonal and up to 80% of tumour-suppressor genes being inactivated bi-allelically by different mutational mechanisms. Although metastatic tumour genomes showed similar mutational landscape and driver genes to primary tumours, we find characteristics that could contribute to responsiveness to therapy or resistance in individual patients. We implement an approach for the review of clinically relevant associations and their potential for actionability. For 62% of patients, we identify genetic variants that may be used to stratify patients towards therapies that either have been approved or are in clinical trials. This demonstrates the importance of comprehensive genomic tumour profiling for precision medicine in cancer.

Trastuzumab and first-line taxane chemotherapy in metastatic breast cancer patients with a HER2-negative tumor and HER2-positive circulating tumor cells: a phase II trial.

PURPOSE: HER2 overexpressing circulating tumor cells (CTCs) are observed in up to 25% of HER2-negative metastatic breast cancer patients. Since targeted anti-HER2 therapy has drastically improved clinical outcomes of patients with HER2-positive breast cancer, we hypothesized that patients with HER2 overexpressing CTCs might benefit from the addition of trastuzumab to chemotherapy. METHODS: In this single-arm, phase II trial, patients with HER2-positive CTCs received trastuzumab as addition to first-line treatment with taxane chemotherapy. Patients with detectable CTCs but without HER2 overexpression that received taxane chemotherapy only, were used as control group. The primary outcome measure was progression-free rate at 6 months (PFR6), with a target of 80%. In November 2022, the study was terminated early due to slow patient accrual. RESULTS: 63 patients were screened, of which eight patients had HER2-positive CTCs and were treated with trastuzumab. The median number of CTCs was 15 per 7.5 ml of blood (range 1-131) in patients with HER2-positive CTCs, compared to median 5 (range 1-1047) in the control group. PFR6 was 50% in the trastuzumab group and 54% in the taxane monotherapy group, with no significant difference in median PFS (8 versus 9 months, p = 0.51). CONCLUSION: No clinical benefit of trastuzumab was observed, although this study was performed in a limited number of patients. Additionally, we observed a strong correlation between the number of evaluable CTCs and the presence of HER2-positive CTCs. We argue that randomized studies investigating agents that are proven to be solely effective in the HER2-positive patient group in patients with HER2-positive CTCs and HER2-negative tissue are currently infeasible. Several factors contribute to this impracticality, including the need for more stringent thresholds, and the rapidly evolving landscape of cancer treatments.

Integrative whole-genome and transcriptome analysis of HER2-amplified metastatic breast cancer.

BACKGROUND: In breast cancer, the advent of anti-HER2 therapies has made HER2+ tumors a highly relevant subgroup. However, the exact characteristics which prohibit clinical response to anti-HER2 therapies and drive disease progression are not yet fully known. Integrative whole-genome and transcriptomic sequencing data from both primary and metastatic HER2-positive breast cancer will enhance our understanding of underlying biological processes. METHODS: Here, we used WGS and RNA sequencing data of 700 metastatic breast tumors, of which 68 being HER2+, to search for specific genomic features of HER2+ disease and therapy resistance. Furthermore, we integrated results with transcriptomic data to associate tumors exhibiting a HER2+-specific gene expression profile with ERBB2 mutation status, prior therapy and relevant gene expression signatures. RESULTS: Overall genomic profiles of primary and metastatic HER2+ breast cancers were similar, and no specific acquired genomics traits connected to prior anti-HER2 treatment were observed. However, specific genomic features were predictive of progression-free survival on post-biopsy anti-HER2 treatment. Furthermore, a HER2-driven expression profile grouped HER2-amplified tumors with ERBB2-mutated cases and cases without HER2 alterations. The latter were reported as ER positive in primary disease, but the metastatic biopsy showed low ESR1 expression and upregulation of the MAPK pathway, suggesting transformation to ER independence. CONCLUSIONS: In summary, although the quantity of variants increased throughout HER2-positive breast cancer progression, the genomic composition remained largely consistent, thus yielding no new major processes beside those already operational in primary disease. Our results suggest that integrated genomic and transcriptomic analyses may be key in establishing therapeutic options.

A Nationwide Prospective Clinical Trial on Active Surveillance in Patients With Non-intraabdominal Desmoid-type Fibromatosis: The GRAFITI Trial.

OBJECTIVE: To assess tumor behavior and the efficacy of active surveillance (AS) in patients with desmoid-type fibromatosis (DTF). SUMMARY OF BACKGROUND DATA: AS is recommended as initial management for DTF patients. Prospective data regarding the results of AS are lacking. METHODS: In this multicenter prospective cohort study (NTR4714), adult patients with non-intraabdominal DTF were followed during an initial AS approach for 3 years. Tumor behavior was evaluated according to Response Evaluation Criteria in Solid Tumors. Cumulative incidence of the start of an active treatment and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Factors predictive for start of active treatment were assessed by Cox regression analyses. RESULTS: A total of 105 patients started with AS. Median tumor size at baseline was 4.1cm (interquartile range 3.0-6.6). Fifty-seven patients had a T41A CTNNB1 mutation; 14 patients a S45F CTNNB1 mutation. At 3 years, cumulative incidence of the start of active treatment was 30% (95% confidence interval [CI] 21-39) and PFS was 58% (95% CI 49-69). Median time to start active treatment and PFS were not reached at a median follow-up of 33.7 months. During AS, 32% of patients had stable disease, 28% regressed, and 40% demonstrated initial progression. Larger tumor size (≥5 cm; hazard ratio = 2.38 [95% CI 1.15-4.90]) and S45F mutation (hazard ratio = 6.24 [95% CI 1.92-20.30]) were associated with the start of active treatment. CONCLUSIONS: The majority DTF patients undergoing AS do not need an active treatment and experience stable or regressive disease, even after initial progression. Knowledge about the natural behavior of DTF will help to tailor the follow-up schedule to the individual patient.

Health-related Quality of Life of Patients With Non-Intra-abdominal Desmoid-Type Fibromatosis During Active Surveillance: Results of a Prospective Observational Study.

OBJECTIVE: To examine the impact of an active surveillance (AS) approach on the health-related quality of life (HRQoL) of patients with desmoid-type fibromatosis (DTF). BACKGROUND DATA: AS is recommended as initial approach in DTF patients. AS might however negatively affect HRQoL due to physical symptoms or stress and anxiety. METHODS: In a prospective observational study, the GRAFITI trial (NTR4714), DTF patients were followed during an initial AS approach for 3 years. HRQoL was assessed by the EORTC QLQ-C30 at baseline, 6, 12 and 24-month follow-up. Patients who completed questionnaires at≥1-time point were included in this analysis of the secondary endpoint. A multivariable linear mixed-effects model with random intercept was conducted to assess trends of HRQoL scores over time and to explore the effect of treatment strategy on HRQoL. RESULTS: All 105 patients enrolled in the GRAFITI trial were eligible for the HRQoL analyses. During 24-month follow-up, 75 patients (71%) continued AS and 30 patients (29%) started an active treatment (AT). DTF patients who continued AS demonstrated relatively stable HRQoL scores during follow-up. HRQoL scores of patients who started AT worsened compared to patients who continued AS, although no significant changes in HRQoL score over time were found in the mixed-model analyses. Overall, DTF patients who started AT scored significantly worse on pain (ß=10.08, P =0.039) compared to patients who continued AS. CONCLUSIONS: An initial AS approach did not impair HRQoL of DTF patients who continued AS over time, therefore providing further support for AS as the frontline approach in DTF patients. Longitudinal assessment of HRQoL should be part of clinical follow-up to identify patients who may need a change in treatment strategy.

Alternative dosing strategies for immune checkpoint inhibitors to improve cost-effectiveness: a special focus on nivolumab and pembrolizumab.

Immune checkpoint inhibitors have revolutionised cancer treatment by offering durable responses to many patients with solid and haematological cancers. The high prices and increasing use of immune checkpoint inhibitors put considerable strain on health-care budgets globally. This financial strain could jeopardise patients' access to these anti-cancer therapies. However, substantial evidence suggests that immune checkpoint inhibitors are being administered at doses that exceed the minimum dose required for maximum anti-tumour efficacy. Therefore, investigating and implementing the most cost-effective dosing strategies for immune checkpoint inhibitors are urgently necessary. This Personal View provides an overview of existing data on immune checkpoint inhibitor pharmacology and (novel) dosing strategies for anti-PD-1 therapy with nivolumab and pembrolizumab, with a special focus on cost-effectiveness and saving potential. Furthermore, specific recommendations to guide health-care professionals are provided, through the process of prescribing, rounding, preparing, and administering nivolumab and pembrolizumab in the most practical and cost-effective way possible.

Personalised selection of experimental treatment in patients with advanced solid cancer is feasible using whole-genome sequencing.

BACKGROUND: Biomarker-guided therapy in an experimental setting has been suggested to improve patient outcomes. However, trial-specific pre-screening tests are time and tissue consuming and complicate the personalised treatment of patients eligible for early-phase clinical trials. In this study the feasibility of whole-genome sequencing (WGS) as a one-test-for-all for guided inclusion in early-phase trials was investigated. METHODS: Phase I Molecular Tumor Board (MTB) at the Erasmus MC Cancer Institute reviewed patients with advanced cancer without standard-of-care treatment (SOC) options for a 'fresh-frozen' (FF) tumour biopsy for WGS based on clinical-pathological features. Clinical grade WGS was performed by Hartwig Medical Foundation. MTB matched the patient with a trial, if available. RESULTS: From September 2019-March 2021, 31 patients with highly diverse tumour types underwent a tumour biopsy for WGS. The median turnaround time (TAT) was 15 days [10-42 days]. At least one actionable event was found in 84% of the patients (26/31). One-third of the patients (11/31) received matched experimental treatment. CONCLUSIONS: WGS on fresh FF biopsies is a feasible tool for the selection of personalised experimental therapy in patients with advanced cancer without SOC options. WGS is now possible in an acceptable TAT and thus could fulfil the role of a universal genomic pre-screening test.

The prognostic and predictive value of ESR1 fusion gene transcripts in primary breast cancer.

BACKGROUND: In breast cancer (BC), recurrent fusion genes of estrogen receptor alpha (ESR1) and AKAP12, ARMT1 and CCDC170 have been reported. In these gene fusions the ligand binding domain of ESR1 has been replaced by the transactivation domain of the fusion partner constitutively activating the receptor. As a result, these gene fusions can drive tumor growth hormone independently as been shown in preclinical models, but the clinical value of these fusions have not been reported. Here, we studied the prognostic and predictive value of different frequently reported ESR1 fusion transcripts in primary BC. METHODS: We evaluated 732 patients with primary BC (131 ESR1-negative and 601 ESR1-positive cases), including two ER-positive BC patient cohorts: one cohort of 322 patients with advanced disease who received first-line endocrine therapy (ET) (predictive cohort), and a second cohort of 279 patients with lymph node negative disease (LNN) who received no adjuvant systemic treatment (prognostic cohort). Fusion gene transcript levels were measured by reverse transcriptase quantitative PCR. The presence of the different fusion transcripts was associated, in uni- and multivariable Cox regression analysis taking along current clinico-pathological characteristics, to progression free survival (PFS) during first-line endocrine therapy in the predictive cohort, and disease- free survival (DFS) and overall survival (OS) in the prognostic cohort. RESULTS: The ESR1-CCDC170 fusion transcript was present in 27.6% of the ESR1-positive BC subjects and in 2.3% of the ESR1-negative cases. In the predictive cohort, none of the fusion transcripts were associated with response to first-line ET. In the prognostic cohort, the median DFS and OS were respectively 37 and 93 months for patients with an ESR1-CCDC170 exon 8 gene fusion transcript and respectively 91 and 212 months for patients without this fusion transcript. In a multivariable analysis, this ESR1-CCDC170 fusion transcript was an independent prognostic factor for DFS (HR) (95% confidence interval (CI): 1.8 (1.2-2.8), P = 0.005) and OS (HR (95% CI: 1.7 (1.1-2.7), P = 0.023). CONCLUSIONS: Our study shows that in primary BC only ESR1-CCDC170 exon 8 gene fusion transcript carries prognostic value. None of the ESR1 fusion transcripts, which are considered to have constitutive ER activity, was predictive for outcome in BC with advanced disease treated with endocrine treatment.

Differential Diagnosis and Molecular Stratification of Gastrointestinal Stromal Tumors on CT Images Using a Radiomics Approach.

Treatment planning of gastrointestinal stromal tumors (GISTs) includes distinguishing GISTs from other intra-abdominal tumors and GISTs' molecular analysis. The aim of this study was to evaluate radiomics for distinguishing GISTs from other intra-abdominal tumors, and in GISTs, predict the c-KIT, PDGFRA, BRAF mutational status, and mitotic index (MI). Patients diagnosed at the Erasmus MC between 2004 and 2017, with GIST or non-GIST intra-abdominal tumors and a contrast-enhanced venous-phase CT, were retrospectively included. Tumors were segmented, from which 564 image features were extracted. Prediction models were constructed using a combination of machine learning approaches. The evaluation was performed in a 100 × random-split cross-validation. Model performance was compared to that of three radiologists. One hundred twenty-five GISTs and 122 non-GISTs were included. The GIST vs. non-GIST radiomics model had a mean area under the curve (AUC) of 0.77. Three radiologists had an AUC of 0.69, 0.76, and 0.84, respectively. The radiomics model had an AUC of 0.52 for c-KIT, 0.56 for c-KIT exon 11, and 0.52 for the MI. The numbers of PDGFRA, BRAF, and other c-KIT mutations were too low for analysis. Our radiomics model was able to distinguish GISTs from non-GISTs with a performance similar to three radiologists, but less observer dependent. Therefore, it may aid in the early diagnosis of GIST, facilitating rapid referral to specialized treatment centers. As the model was not able to predict any genetic or molecular features, it cannot aid in treatment planning yet.

ESR1 Methylation Measured in Cell-Free DNA to Evaluate Endocrine Resistance in Metastatic Breast Cancer Patients.

ESR1 methylation was proposed as mechanism for endocrine resistance in metastatic breast cancer patients. To evaluate its potential as a minimally invasive biomarker, we investigated the feasibility of measuring ESR1 methylation in cell-free DNA (cfDNA) and its association with endocrine resistance. First, we provided evidence that demethylation in vitro restores ER expression. Subsequently, we found that ESR1 methylation in cfDNA was not enriched in endocrine-resistant versus endocrine-sensitive patients. Interestingly, we found a correlation between ESR1 methylation and age. Publicly available data confirm an age-related increase in ESR1 methylation in leukocytes, confounding the determination of the ESR1 methylation status of tumors using cfDNA.

The Prognostic Role of ß-Catenin Mutations in Desmoid-type Fibromatosis Undergoing Resection Only: A Meta-analysis of Individual Patient Data.

OBJECTIVE: This meta-analysis (PROSPERO CRD42018100653) uses individual patient data (IPD) to assess the association between recurrence and CTNNB1 mutation status in surgically treated adult desmoid-type fibromatosis (DTF) patients. SUMMARY OF BACKGROUND DATA: The majority of sporadic DTF tumors harbor a CTNNB1 (ß-catenin) mutation: T41A, S45F, and S45P or are wild-type (WT). Results are conflicting regarding the recurrence risk after surgery for these mutation types. METHODS: A systematic literature search was performed on June 6th, 2018. IPD from eligible studies was used to analyze differences in recurrence according to CTNNB1 mutation status using Cox proportional hazards analysis. Predictive factors included: sex, age, mutation type, tumor site, tumor size, resection margin status, and cohort. The PRISMA-IPD guideline was used. RESULTS: Seven studies, describing retrospective cohorts were included and the IPD of 329 patients were used of whom 154 (46.8%) had a T41A mutation, 66 (20.1%) a S45F mutation, and 24 (7.3%) a S45P mutation, whereas 85 (25.8%) patients had a WT CTNNB1. Eighty-three patients (25.2%) experienced recurrence. Multivariable analysis, adjusting for sex, age, and tumor site yielded a P-value of 0.011 for CTNNB1 mutation. Additional adjustment for tumor size yielded a P-value of 0.082 with hazard ratio's of 0.83 [95% confidence interval (CI) 0.48-1.42), 0.37 (95% CI 0.12-1.14), and 0.44 (95% CI 0.21-0.92) for T41A, S45P and WT DTF tumors compared to S45F DTF tumors. The effect modification between tumor size and mutation type suggests that tumor size is an important mediator for recurrence. CONCLUSIONS: Primary sporadic DTFs harboring a CTNNB1 S45F mutation have a higher risk of recurrence after surgery compared to T41A, S45P, and WT DTF, but this association seems to be mediated by tumor size.

Detection of tumor-derived extracellular vesicles in plasma from patients with solid cancer.

BACKGROUND: Extracellular vesicles (EVs) are actively secreted by cells into body fluids and contain nucleic acids of the cells they originate from. The goal of this study was to detect circulating tumor-derived EVs (ctEVs) by mutant mRNA transcripts (EV-RNA) in plasma of patients with solid cancers and compare the occurrence of ctEVs with circulating tumor DNA (ctDNA) in cell-free DNA (cfDNA). METHODS: For this purpose, blood from 20 patients and 15 healthy blood donors (HBDs) was collected in different preservation tubes (EDTA, BCT, CellSave) and processed into plasma within 24 h from venipuncture. EVs were isolated with the ExoEasy protocol from this plasma and from conditioned medium of 6 cancer cell lines and characterized according to MISEV2018-guidelines. RNA from EVs was isolated with the ExoRNeasy protocol and evaluated for transcript expression levels of 96 genes by RT-qPCR and genotyped by digital PCR. RESULTS: Our workflow applied on cell lines revealed a high concordance between cellular mRNA and EV-RNA in expression levels as well as variant allele frequencies for PIK3CA, KRAS and BRAF. Plasma CD9-positive EV and GAPDH EV-RNA levels were significantly different between the preservation tubes. The workflow detected only ctEVs with mutant transcripts in plasma of patients with high amounts (> 20%) of circulating tumor DNA (ctDNA). Expression profiling showed that the EVs from patients resemble healthy donors more than tumor cell lines supporting that most EVs are derived from healthy tissue. CONCLUSIONS: We provide a workflow for ctEV detection by spin column-based generic isolation of EVs and PCR-based measurement of gene expression and mutant transcripts in EV-RNA derived from cancer patients' blood plasma. This workflow, however, detected tumor-specific mutations in blood less often in EV-RNA than in cfDNA.

Impact of panel design and cut-off on tumour mutational burden assessment in metastatic solid tumour samples.

Tumour mutational burden (TMB) has emerged as a promising biomarker to predict immune checkpoint inhibitors (ICIs) response in advanced solid cancers. However, harmonisation of TMB reporting by targeted gene panels is lacking, especially in metastatic tumour samples. To address this issue, we used data of 2841 whole-genome sequenced metastatic cancer biopsies to perform an in silico analysis of TMB determined by seven gene panels (FD1CDx, MSK-IMPACT™, Caris Molecular Intelligence, Tempus xT, Oncomine Tumour Mutation Load, NeoTYPE Discovery Profile and CANCERPLEX) compared to exome-based TMB as a golden standard. Misclassification rates declined from up to 30% to <1% when the cut-point for high TMB was increased. Receiver operating characteristic analysis demonstrated that, for correct classification, the cut-point for each gene panel may vary more than 20%. In conclusion, we here demonstrate that a major limitation for the use of gene panels is inter-assay variation and the need for dynamic thresholds to compare TMB outcomes.

Non-Coding RNAs, a Novel Paradigm for the Management of Gastrointestinal Stromal Tumors.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal malignancies found in the gastrointestinal tract. At a molecular level, most GISTs are characterized by gain-of-function mutations in V-Kit Hardy-Zuckerman 4 Feline Sarcoma Viral Oncogene Homolog (KIT) and Platelet Derived Growth Factor Receptor Alpha (PDGFRA), leading to constitutive activated signaling through these receptor tyrosine kinases, which drive GIST pathogenesis. In addition to surgery, treatment with the tyrosine kinase inhibitor imatinib forms the mainstay of GIST treatment, particularly in the advanced setting. Nevertheless, the majority of GISTs develop imatinib resistance. Biomarkers that indicate metastasis, drug resistance and disease progression early on could be of great clinical value. Likewise, novel treatment strategies that overcome resistance mechanisms are equally needed. Non-coding RNAs, particularly microRNAs, can be employed as diagnostic, prognostic or predictive biomarkers and have therapeutic potential. Here we review which non-coding RNAs are deregulated in GISTs, whether they can be linked to specific clinicopathological features and discuss how they can be used to improve the clinical management of GISTs.

Androgen receptor expression in circulating tumor cells of patients with metastatic breast cancer.

The androgen receptor (AR) has potential clinical relevance in metastatic breast cancer (mBC) since it might be a treatment target and has been associated with endocrine resistance. A minimal-invasive way to determine AR expression on metastatic tumor cells is by characterization of circulating tumor cells (CTCs). Here, we assessed AR mRNA expression in CTCs (CTC-AR) and in matched primary tumor samples from mBC patients representing different breast cancer subtypes. In addition, we explored CTC-AR-status in relation to outcome on endocrine therapy. AR, and 92 AR or estrogen receptor (ER) related genes, were measured in CellSearch-enriched CTCs from 124 mBC patients and in 52 matched FFPE primary tissues using quantitative reverse-transcriptase PCR. AR in CTCs was considered positive if the expression was 1 standard deviation higher than the expression measured in 11 healthy blood donors. A total of 31% of the mBC patients had AR-positive (AR+) CTCs. 58% of the matched CTC and primary tumor samples were discordant with respect to AR status, observing both switches from AR+ to AR-negative (AR-) and vice versa. There was no statistically significant difference in progression-free survival for patients treated with ER-targeting drugs and CTC-AR-status (13 AR+/ 37 AR- cases, p = 0.28). Thus, AR can be determined in RNA isolated from CTCs, with in our set 31% AR-positive samples. Given the discordance between AR status in CTC samples and corresponding primary tumors, determination of AR expression in CTCs might be a promising tool to select mBC patients for AR inhibiting agents.

Minimal Increase in Survival Throughout the Years in Patients with Soft Tissue Sarcoma with Synchronous Metastases: Results of a Population-Based Study.

BACKGROUND: Treatment options for patients with metastatic soft tissue sarcoma (STS) have increased in the last decade. We aimed to examine whether this is associated with improved overall survival (OS) in patients with STS with synchronous metastases. PATIENTS AND METHODS: Patients diagnosed with STS and synchronous metastases from 1989 to 2014 were queried from The Netherlands Cancer Registry. Trends in OS were assessed by the Kaplan-Meier method and log-rank test in time intervals of 5 years, for the whole study population and in subgroups for liposarcomas, leiomyosarcoma, and other STS subtypes. A multivariable Cox regression analysis was performed to identify characteristics prognostic for OS. RESULTS: Median OS of the 1,393 identified patients did not improve significantly over the years from 5.8 months in 1989-1994 to 8.1 months in 2010-2014, but there was an evident trend. Median OS was prolonged in the subgroups of liposarcomas (3.6 to 9.3 months), leiomyosarcomas (11.3 to 14.6 months), and other STS subtypes (5.7 to 6.3 months), although there were no significant improvements in OS over the years. Primary tumor site in one of the extremities and surgery in an academic center had a favorable effect on OS, whereas significant negative predictors were no treatment, elderly age, STS subtype other than liposarcoma or leiomyosarcoma, high or unknown grade, and nodal involvement. CONCLUSION: Although overall survival of patients with STS with synchronous metastases in this nationwide and "real-life" population has improved over the years, the improvement was not statistically significant, despite new treatment options. IMPLICATIONS FOR PRACTICE: Treatment of patients with metastatic soft tissue sarcoma (STS) has changed in the past years, with new drugs such as trabectedin (2007) and pazopanib (2012) becoming available. By using data from the nationwide Netherlands Cancer Registry, the impact of these changes in treatment policies on survival is analyzed in a "real-life" population of patients with STS with synchronous metastases, rather than in a strictly selected trial population. Unfortunately, overall survival improved only minimally and not significantly for these patients diagnosed from 1989 to 2014. Hopefully, the advent of novel treatment options, such as eribulin and olaratumab, will further improve the outcome of this patient group.

Real-world data on discordance between estrogen, progesterone, and HER2 receptor expression on diagnostic tumor biopsy versus tumor resection material.

PURPOSE: The estrogen (ER), progesterone (PR), and HER2 status are essential in guiding treatment decisions in breast cancer patients. In daily life, the ER/PR/HER2 status is expected to be commonly tested twice, i.e., at diagnosis using material from tumor needle biopsies, and after tumor resection using full tumor tissue material. This study explored the discordance of ER/PR/HER2 between tumor needle biopsies and full tumor resection material using real-world patient-level data from Dutch breast cancer patients. METHODS: Pathology reports of 11,054 breast cancer patients were derived from PALGA (Dutch Pathology Registry). Discordance was calculated for multiple combinations of the ER/PR/HER2 receptor status. The influence of patient and tumor characteristics on the probability of having discordant test results was analyzed using multiple logistic regression models (separately for ER, PR and HER2). RESULTS: For 1279 patients (14.4%), at least one of the receptors (ER/PR/HER2) was determined on both biopsy and tumor tissue material. The majority had concordant test results for ER (n = 916; 94.8%), PR (n = 1170; 86.7%), and HER2 (n = 881; 98.1%). Patients having an ER- and HER2-positive but PR-negative biopsy classification, BR grade III, and < 10% tumor tissue remaining after neoadjuvant therapy (NAT) have the highest probability of ER discordant test results (OR 4.991; p = 83.31%). The probability of discordance in PR is based on different sets of patient and tumor characteristics. Potential cost savings from omitting multiple tests if concordance can be perfectly predicted can be up to €205,000 yearly. CONCLUSIONS: Double testing of ER/PR/HER2 is less common than expected. Discordance in ER/PR/HER2 test results between tumor needle biopsy taken at the time of diagnosis and tumor resection material is very low, especially in patients not receiving any form of neoadjuvant therapy. These results imply that a substantial number of tests can potentially be omitted in specific subgroups of breast cancer patients.

Genetic polymorphisms in ABCG2 and CYP1A2 are associated with imatinib dose reduction in patients treated for gastrointestinal stromal tumors.

Imatinib has a mild toxicity profile, although severe adverse events may develop. In this pharmacogenetic pathway analysis the need for dose reduction and cessation of therapy was tested for an association with single nucleotide polymorphisms (SNPs) in genes related to imatinib pharmacology. Retrospective data from 315 patients with a gastrointestinal stromal tumor who received imatinib 400 mg o.d. was associated with 36 SNPs. SNPs that showed a trend in univariate testing were tested in a multivariate model with clinical factors and correction for multiple testing was performed. Dose reduction was associated with carriership of the A-allele in rs2231137 in ABCG2 (OR 7.35, p = 0.0002) and two C-alleles in rs762551 in CYP1A2 (OR 7.12, p = 0.001). Results remained significant after correction for multiple testing. Therapy cessation did not show an association with any of the tested SNPs. These results may help identifying patients at increased risk for toxicity who could benefit from intensified follow-up.

Association of pazopanib-induced toxicities with outcome of patients with advanced soft tissue sarcoma; a retrospective analysis based on the European Organisation for Research and Treatment of Cancer (EORTC) 62043 and 62072 clinical trials.

Background: There is an unmet need for markers predicting the outcome of patients with advanced soft tissue sarcoma (STS) treated with pazopanib. Since toxicity might be related to the anti-tumor activity of the drug, the aim of this study was to determine whether pazopanib-induced proteinuria, hypothyroidism and cardiotoxicity grade 3-4 were associated with outcome. Methods: The combined results of the EORTC 62043 and 62072 trials were retrospectively assessed and used in a landmark analysis to evaluate the effect of the toxicities on progression-free survival (PFS) and overall survival (OS), using the Kaplan-Meier method and Cox regression models. Results: Of the 333 eligible patients, 259 patients were included in the analyses, for which a landmark time point of 60 days after randomization/registration was selected. Proteinuria occurred in 25.1%, hypothyroidism in 22.0% and cardiotoxicity grade 3-4 in 5.8% of the patients (any grade in 41.7%). There was no effect of the occurrence of proteinuria (6-months PFS 35.4% for patients with vs. 38.3% for patients without proteinuria, HR 1.01, p = .953), hypothyroidism (41.2% vs. 36.5%, HR 0.82, p = .210) or cardiotoxicity grade 3-4 (26.7% vs. 38.2%, HR 0.97, p = .897) on PFS. Nor was there an effect of proteinuria (6-months OS 63.2% for patients with vs. 74.4% for patients without proteinuria, HR 1.22, p = .196), hypothyroidism (76.2% vs. 70.5%, HR 0.75, p = .093) or cardiotoxicity grade 3-4 (80.0% vs. 77.2%, HR 0.93, p = .801) on OS. Conclusion: There was no association between the occurrence of pazopanib-induced proteinuria, hypothyroidism and cardiotoxicity and outcome. Therefore, these toxicities cannot be used as predictors for pazopanib activity in patients with advanced STS.

Self-Seeding Microwells to Isolate and Assess the Viability of Single Circulating Tumor Cells.

The availability of viable tumor cells could significantly improve the disease management of cancer patients. Here we developed and evaluated a method using self-seeding microwells to obtain single circulating tumor cells (CTC) and assess their potential to expand. Conditions were optimized using cells from the breast cancer cell line MCF-7 and blood from healthy volunteers collected in EDTA blood collection tubes. 43% of the MCF-7 cells (nucleus+, Ethidium homodimer-1-, Calcein AM+, α-EpCAM+, α-CD45-) spiked into 7.5 mL of blood could be recovered with 67% viability and these could be further expanded. The same procedure tested in metastatic breast and prostate cancer patients resulted in a CTC recovery of only 0⁻5% as compared with CTC counts obtained with the CellSearch® system. Viability of the detected CTC ranged from 0⁻36%. Cell losses could be mainly contributed to the smaller size and greater flexibility of CTC as compared to cultured cells from cell lines and loss during leukocyte depletion prior to cell seeding. Although CTC losses can be reduced by fixation, to obtain viable CTC no fixatives can be used and pore size in the bottom of microwells will need to be reduced, filtration conditions adapted and pre-enrichment improved to reduce CTC losses.