Initial versus early switch to targeted therapy during first-line treatment among patients with biomarker-positive advanced or metastatic non-small cell lung cancer in the United States.

OBJECTIVES: This study compared outcomes between patients with biomarker-positive advanced/metastatic non-small cell lung cancer (a/mNSCLC) who initiated treatment with targeted therapy versus those who initiated chemotherapy-based treatment and switched to targeted therapy during the first ∼3 cycles (defined as the first 56 days) of first-line treatment. MATERIALS AND METHODS: This was an observational study of patients with a/mNSCLC who received targeted therapy from a nationwide electronic health record (EHR)-derived de-identified database. Outcomes were compared between those who initiated targeted therapy versus those who switched from chemotherapy to a targeted agent. Time-to-event outcomes were evaluated using Kaplan-Meier method; Cox proportional hazards models (adjusted for baseline covariates) were used to compare outcomes between groups. RESULTS: Of the 4,244 patients in this study, 3,107 (73.2%) initiated the first line with targeted therapy and 346 (8.2%) switched to targeted therapy. Patients who received initial targeted therapy were significantly more likely to be non-smokers, treated in an academic practice setting, and of slightly older age (all p < 0.05). Patients who received initial targeted therapy also had a significantly longer time to start of first-line treatment (35.8 vs 25.3 days, p < 0.001). No significant differences were observed for clinical outcomes between groups. CONCLUSION: In both unadjusted and adjusted analyses, there were no differences in the clinical outcomes observed among patients with a/mNSCLC in this study. This study found that initiating chemotherapy with an early switch to targeted therapy (within 56 days) of receiving biomarker positive results may be an acceptable strategy for a patient for whom immediate care is needed.

Challenges in the care of patients with RET-altered thyroid cancer: a multicountry mixed-methods study.

BACKGROUND: The discovery of driver oncogenes for thyroid carcinomas and the identification of genomically targeted therapies to inhibit those oncogenes have altered the treatment algorithm in thyroid cancer (TC), while germline testing for RET mutations has become indicated for patients with a family history of RET gene mutations or hereditary medullary TC (MTC). In the context of an increasing number of selective RET inhibitors approved for use, this paper aims to describe challenges and barriers affecting providers' ability to deliver optimal care for patients with RET-altered TC across the patient healthcare journey. METHODS: A mixed-method educational and behavioral needs assessment was conducted in Germany (GER), Japan (JPN), the United Kingdom (UK), and the United States (US) prior to RET-selective inhibitor approval. Participants included medical oncologists (MO), endocrinologists (EN) and clinical pathologists (CP) caring for patients affected with TC. Data collection tools were implemented in three languages (English, German, Japanese). Qualitative data were coded and thematically analyzed in NVivo. Quantitative data were analyzed via frequency and crosstabulations in SPSS. The findings presented here were part of a broader study that also investigated lung cancer challenges and included pulmonologists. RESULTS: A total of 44 interviews and 378 surveys were completed. Suboptimal knowledge and skills were self-identified among providers, affecting (1) assessment of genetic risk factors (56%, 159/285 of MOs and ENs), (2) selection of appropriate genetic biomarkers (59%, 53/90 of CPs), (3) treatment plan initiation (65%, 173/275 of MOs and ENs), (4) management of side effects associated with multitargeted tyrosine kinase inhibitors (78%, 116/149 of MOs and ENs), and (5) transfer of patients into palliative care services (58%, 160/274 of MOs and ENs). Interviews underscored the presence of systemic barriers affecting the use of RET molecular tests and selective inhibitors, in addition to suboptimal knowledge and skills necessary to manage the safety and efficacy of targeted therapies. CONCLUSION: This study describes concrete educational needs for providers involved in the care of patients with RET-altered thyroid carcinomas. Findings can be used to inform the design of evidence-based education and performance improvement interventions in the field and support integration into practice of newly approved RET-selective inhibitors.

Challenges in diagnosis and biomarker testing for RET-altered lung and thyroid cancer care: an international mixed-method study.

BACKGROUND: The introduction of new targeted therapies for RET-altered lung and thyroid cancers (LC/TC) has impacted pathologists' practice by making genomic testing more relevant. Variations in health systems and treatment access result in distinct clinical challenges and barriers. This study aimed to assess practice gaps and challenges experienced by pathologists involved in the diagnosis of RET-altered LC/TC, including biomarker testing, to inform educational solutions. METHODS: Pathologists in Germany, Japan, the UK, and US participated in this ethics-approved mixed-methods study, which included interviews and surveys (data collected January-March 2020). Qualitative data was thematically analysed, quantitative data was analysed with chi-square and Kruskal-Wallis H-tests, and both were triangulated. RESULTS: A total of 107 pathologists took part in this study. Knowledge gaps were reported regarding genomic testing for LC/TC in Japan (79/60%), the UK (73/66%), and the US (53/30%). Skill gaps were reported when selecting genomic biomarker tests to diagnose TC in Japan (79%), the UK (73%) and US (57%) and when performing specific biomarker tests, especially in Japan (82% for RET) and in the UK (75% for RET). Japanese participants (80%) reported uncertainty about what information to share with the multidisciplinary team to ensure optimal patient-centered care. At the time of data collection, pathologists in Japan faced access barriers to using RET biomarker tests: only 28% agreed that there are relevant RET genomic biomarker tests available in Japan, versus 67% to 90% in other countries. CONCLUSIONS: This study identified areas where pathologists need additional continuing professional development opportunities to enhance their competencies and better support delivery of care to patients with RET-altered lung or thyroid tumours. Addressing identified gaps and improving competencies of pathologists in this field should be emphasised in continuing medical education curricula and through quality improvement initiatives. Strategies deployed on an institutional and health system level should aim to improve interprofessional communication and genetic biomarker testing expertise.

Real-World Biomarker Testing Patterns in Patients With Metastatic Non-Squamous Non-Small Cell Lung Cancer (NSCLC) in a US Community-Based Oncology Practice Setting.

INTRODUCTION/BACKGROUND: This study was designed to describe real-world changes in biomarker testing among patients with non-squamous, metastatic non-small cell lung cancer (mNSCLC) in a community oncology setting from 2015 to 2020. PATIENTS AND METHODS: This retrospective study randomly selected 500 adult patients diagnosed with nonsquamous mNSCLC to undergo chart review and data extraction. Data were extracted and validated by 2 independent abstractors. Biomarker testing rates were described before and after national guideline updates and FDA approval of targeted agents. RESULTS: At least 1 biomarker test was received by 89.4% of patients with mNSCLC. Of all patients, 46.6%, 34.6%, and 8.2% received both single-gene and next generation sequencing (NGS)-based testing, single-gene testing only, and NGS-based testing only, respectively. However, there were changes in testing rates at the time of drug approvals for targeted agents. Biomarker testing increased for ALK (45.0% before to 78.3% after ALK-targeted drug approval), BRAF (from 20.0% to 67.8%), EGFR (from 20.0% to 78.2%), NTRK (from 34.6% to 55.7%), and ROS1 (increased from 29.6% before approval to 74.2% after). Biomarker testing increased after changes were made to national guidelines for BRAF (from 18.8% before to 68.1% after inclusion in guidelines), NTRK (from 37.2% to 56.5%), and ROS1 (increased from 40.8% to 74.5% after guideline updates). Targeted therapy was received by 62.4% of patients with a positive biomarker. CONCLUSION: Increases in biomarker testing rates were observed relative to targeted agent approvals and national guideline updates. However, many patients with non-squamous mNSCLC did not receive full genotyping in accordance with national guidelines and represent an opportunity to identify reasons and solutions for barriers to care.

Biomarker testing in patients diagnosed with advanced/metastatic medullary thyroid cancer in the USA.

Aim: To describe real-world testing patterns for RET in US patients with advanced/metastatic medullary thyroid cancer and determine consistency of real-world testing practices with national guidelines. Materials & methods: The authors performed a retrospective medical record analysis of patients with advanced/metastatic medullary thyroid cancer who initiated systemic therapy between 2013 and 2018. Seventy-five US-based oncologists collected the data using a customized electronic data collection form. Results: A total of 59.6% (121 of 203) of patients underwent testing for RET, and 37.2% (45 of 121) had a RET mutation, of which 55.6% were identified as RET mutation-positive before initial diagnosis. Overall, 90 (44.3%) patients were tested for biomarkers on or after initial diagnosis, with RET being the most tested (95.6%) biomarker. Conclusion: The authors' findings suggest an opportunity to improve testing rates in accordance with treatment guidelines.

Mutations in the RET gene are common in patients with medullary thyroid cancer (MTC). As RET mutations are involved in the development of MTC, several treatment guidelines recommend counseling patients and testing for mutations in the RET gene in all patients with MTC. However, limited data are available on RET testing patterns in the USA in this patient population. In this study, the authors determined testing patterns for RET in patients with advanced or metastatic MTC in the USA using real-world data and found that only 60% of patients were tested for RET (i.e., testing for presence of RET mutations was observed in less than two-thirds of all patients included in the study). These results demonstrate the need for improved testing for RET mutations in patients with MTC in alignment with the treatment guidelines in routine clinical practice in the USA.

Costs of biomarker testing among patients with metastatic lung or thyroid cancer in the USA: a real-world commercial claims database study.

OBJECTIVE: This real-world retrospective database study quantified the costs of biomarker testing in a US population of patients with lung or thyroid cancers. MATERIALS AND METHODS: The commercial claims IBM Marketscan database, a de-identified real-world dataset, was used to identify patients diagnosed with lung or thyroid cancer between 1/2015 and 12/2019. Eligible patients were 18 years or older with two or more lung or thyroid diagnosis codes. Patients were excluded who had evidence of prior cancer diagnoses. Subgroup analyses evaluated eligible patients with metastatic disease. Descriptive statistics were used to evaluate commercial insurance plan payer and patient out-of-pocket costs for diagnostic testing overall as well as by test procedure code and payer type. Costs were adjusted to 2020 US dollars. RESULTS: A total of 23,633 patients with lung cancer were eligible, 13,320 of whom had metastatic disease. There were 36,867 patients with thyroid cancer, 2,241 of whom had metastatic disease. Biomarker codes were observed among 68.4/75.8% (lung/metastatic lung) and 18.2/42.3% (thyroid/metastatic thyroid). Few patients had codes for comprehensive biomarker tests (5.2/6.7% lung/metastatic lung, 0.3/2.2% thyroid/metastatic thyroid) Among those with biomarker tests, the median per-patient total payer lifetime costs of all biomarker testing were $394/$462 (lung/metastatic lung) and $148/$232 (thyroid/metastatic thyroid). Total lifetime biomarker costs for payers ranged from a median of $128 (consumer-driven health plans) to $477 (preferred provider organizations). Median lifetime patient out-of-pocket costs were $0.00 for both tumor types and all payer types except for consumer-driven health plans ($12 for thyroid and $10 for metastatic lung). CONCLUSIONS: While comprehensive testing adds to the cost of biomarker testing, these data suggest the relatively low lifetime cost of biomarker testing for both payers and patients. Costs for biomarker testing should not be a limitation to access among these populations with commercial insurance plans in the US.

This real-world retrospective database study found that there is a relatively low lifetime total cost of biomarker testing for the care of patients with lung or thyroid cancers. While comprehensive testing adds to the cost of biomarker testing, these data suggest the relatively low lifetime cost of biomarker testing for both payers and patients. Payer costs for biomarker testing do not appear to be limitation to access among populations with commercial insurance plans in this study.

Biomarker Testing for Patients With Advanced/Metastatic Nonsquamous NSCLC in the United States of America, 2015 to 2021.

Introduction: NSCLC is a solid tumor with a growing number of actionable biomarkers that may inform treatment. Current guidelines recommend a broad, panel-based approach be taken to identify actionable markers. This retrospective study used a deidentified electronic health records database in the United States to evaluate utilization of various testing modalities. Methods: Data from all adult patients diagnosed with having advanced/metastatic nonsquamous NSCLC between January 2015 and March 2021 were eligible if there was evidence of systemic therapy within 90 days of diagnosis. Results: Records from a total of 17,513 patients (91.6% from community-based practices) were eligible with 83,064 genomic biomarker tests recorded from 2015 to 2021. The proportion of patients who received biomarker testing by next-generation sequencing (NGS)-based methods ranged from 28.3% in 2015 to 68.1% in 2020. The proportion of biomarker testing methods with inconclusive or unsuccessful results ranged from 3.4% for NGS to 9.7% for fluorescence in situ hybridization. The median time to receive results ranged from 4.0 days for polymerase chain reaction-based tests to 10.0 days for immunohistochemistry- and NGS-based tests. Median time to receive results was 8 days for academic and 9 days for community practices. Conclusions: These real-world data suggest increased adoption of NGS-based testing, yet nearly one-third of all patients with advanced/metastatic nonsquamous NSCLC still did not receive broad-based genomic testing by 2020.

Analytical Accuracy of RET Fusion Detection by Break-Apart Fluorescence In Situ Hybridization.

CONTEXT.­: RET gene fusions are oncogenic drivers in nonsmall cell lung cancer and nonmedullary thyroid cancer. Selpercatinib (RETEVMO), a targeted inhibitor of RET, was approved by the US Food and Drug Administration for the treatment of RET fusion-positive nonsmall cell lung cancer and nonmedullary thyroid cancer emphasizing the need for rapid and accurate diagnosis of RET fusions. Fluorescence in situ hybridization (FISH) has been used to detect gene rearrangements, but its performance detecting RET rearrangements is understudied. OBJECTIVE.­: To validate and describe the performance of Abbott Molecular RET break-apart FISH probes for detecting RET rearrangements. DESIGN.­: A training set with RET fusion-positive (13) and RET fusion-negative nonsmall cell lung cancer and nonmedullary thyroid cancer samples (12) was used to establish criteria for FISH scoring. The scoring criteria was then applied to a larger validation set of samples (96). RESULTS.­: A cutoff of 19% or more positive nuclei by FISH was established in the training set and determined by the mean ±3 SD. The validation set was tested using Abbott Molecular RET break-apart FISH compared with sequencing. With this cutoff, a sensitivity of 86% (12 of 14) and specificity of 99% (81 of 82) was achieved. Bootstrapping showed sensitivity could be optimized by using a greater than 13% cutoff with indeterminate samples of 13% to 18% abnormal nuclei requiring confirmation by an orthogonal method. Using this 3-tier scoring system sensitivity increased to 100% (14 of 14) and specificity was 96% (79 of 82). CONCLUSIONS.­: Abbott Molecular break-apart FISH probes can be used to detect RET fusions. Laboratories can optimize cutoffs and/or testing algorithms to maximize sensitivity and specificity to ensure appropriate patients receive effective, timely therapy.

Efficacy of immune checkpoint inhibitor therapy in patients with RET fusion-positive non-small-cell lung cancer.

Aim: To describe outcomes of patients with rearraned during transfection (RET) fusion-positive non-small-cell lung cancer (NSCLC) who received immune checkpoint inhibitor (ICI)-based treatments in the US. Patients & methods: Using de-identified Flatiron Health-Foundation Medicine NSCLC Clinico-Genomic and Guardant Health databases, treatment patterns and outcomes of 69 patients with advanced/metastatic RET fusion-positive NSCLC who received ICI-based treatment were described. Results: Median real-world progression-free survival and overall survival months were 4.2 (95% CI: 1.4-8.4) and 19.1 (6.9-not reached), respectively, among patients in Clinico-Genomic database (n = 17) receiving first-line ICI-based therapy. In the Guardant Health database, progression-free survival was unavailable, and the median overall survival was not reached (n = 29). Conclusion: Outcomes associated with ICI-based treatments in the first-line setting among patients with RET fusion-positive NSCLC are consistent with unselected populations reported in literature.

Lay abstract Treatment options are rapidly expanding for patients who are diagnosed with advanced/metastatic non-small-cell lung cancer. The current standard of care for patients who do not have an actionable genomic alteration includes immune checkpoint inhibitor (ICI)-based therapy. However, the role of ICI-based therapy is not well understood in patients with rearranged during transfection (RET) fusions. In this study, the survival outcomes observed in patients with RET fusion-positive non-small-cell lung cancer who received first-line ICI-based therapy were comparable with published data from patients without genomic alterations. This study is limited due to the small sample size.

Characteristics and outcomes of patients with RET-fusion positive non-small lung cancer in real-world practice in the United States.

BACKGROUND: Contradictory and limited data are available about the presentation and outcomes of patients with RET-fusion positive metastatic NSCLC as compared to patients without RET fusions. This observational study utilizing a linked electronic health records (EHR) database to genomics testing results was designed to compare characteristics, tumor response, progression-free (PFS) and overall survival (OS) outcomes by RET fusion status among patients with metastatic NSCLC treated with standard therapies. METHODS: Adult patients with metastatic NSCLC with linked EHR and genomics data were eligible who received systemic anti-cancer therapy on or after January 1, 2011. Adjusted, using all available baseline covariates, and unadjusted analyses were conducted to compare tumor response, PFS and OS between patients with RET-fusion positive and RET-fusion negative disease as detected by next-generation sequencing. Tumor response outcomes were analysed using Fisher's exact test, and time-to-event analyses were conducted using Cox proportional hazards model. RESULTS: There were 5807 eligible patients identified (RET+ cohort, N = 46; RET- cohort, N = 5761). Patients with RET fusions were younger, more likely to have non-squamous disease and be non-smokers and had better performance status (all p < 0.01). In unadjusted analyses, there were no significant differences in tumor response (p = 0.17) or PFS (p = 0.06) but OS was significantly different by RET status (hazard ratio, HR = 1.91, 95% CI:1.22-3.0, p = 0.005). There were no statistically significant differences by RET fusion status in adjusted analyses of either PFS or OS (PFS HR = 1.24, 95% CI:0.86-1.78, p = 0.25; OS HR = 1.52, 95% CI: 0.95-2.43, p = 0.08). CONCLUSIONS: Patients with RET fusions have different baseline characteristics that contribute to favorable OS in unadjusted analysis. However, after adjusting for baseline covariates, there were no significant differences in either OS or PFS by RET status among patients treated with standard therapy prior to the availability of selective RET inhibitors.

Molecular Pathology Economics 101: An Overview of Molecular Diagnostics Coding, Coverage, and Reimbursement: A Report of the Association for Molecular Pathology.

Widespread indications for use of molecular diagnostics in various aspects of clinical medicine have driven proliferation of testing. The rapid adoption and continuous technological evolution of molecular diagnostics have often strained the development and maintenance of a functional underlying framework of coding, coverage, and reimbursement policies, thereby presenting challenges to various stakeholders, including molecular professionals, payers, and patients. A multidisciplinary working group convened by the Association for Molecular Pathology Economic Affairs Committee was tasked to describe the complex landscape of molecular pathology economics and highlight opportunities for member engagement. In this article, on the basis of review and synthesis of government regulations and procedures, published payer policy documents, peer-reviewed literature, and expert consensus, the Working Group navigates the ecosystem of molecular pathology economics in terms of stakeholders, coding systems and processes, coverage policy determination, and pricing mechanisms. The composition and interrelatedness of various working groups and committees are emphasized to highlight the functional underpinnings of the system. Molecular professionals must be conversant in the language and complex inner workings of molecular pathology economics to lead successful, viable laboratories and advocate effectively for policy development on their behalf. This overview is provided to be a resource to molecular professionals as they navigate the reimbursement landscape.

Clinical Utilization, Utility, and Reimbursement for Expanded Genomic Panel Testing in Adult Oncology.

PURPOSE: The routine use of large next-generation sequencing (NGS) pan-cancer panels is required to identify the increasing number of, but often uncommon, actionable alterations to guide therapy. Inconsistent coverage and variable payment is hindering NGS adoption into clinical practice. A review of test utilization, clinical utility, coverage, and reimbursement was conducted in a cohort of patients diagnosed with high-risk cancer who received pan-cancer panel testing as part of their clinical care. MATERIALS AND METHODS: The Columbia Combined Cancer Panel (CCCP), a 467-gene panel designed to detect DNA variations in solid and liquid tumors, was performed in the Laboratory of Personalized Genomic Medicine at Columbia University Irving Medical Center. Utilization was characterized at test order. Results were reviewed by a molecular pathologist, followed by a multidisciplinary molecular tumor board where clinical utility was classified by consensus. Reimbursement was reviewed after payers provided final coverage decisions. RESULTS: NGS was performed on 359 high-risk tumors from 349 patients. Reimbursement data were available for 246 cases. The most common reason providers ordered CCCP testing was for patients diagnosed with a treatment-resistant or recurrent tumor (n = 214; 61%). Findings were clinically impactful for 229 cases (64%). Molecular alterations that may inform future therapy in the event of progression or relapse were found in 42% of cases, and a targeted therapy was initiated in 23 cases (6.6%). The majority of tests were denied coverage by payers (n = 190; 77%). On average, insurers reimbursed 10.75% of the total NGS service charge. CONCLUSION: CCCP testing identified clinically impactful alterations in 64% of cases. Limited coverage and low reimbursement remain barriers, and broader reimbursement policies are needed to adopt pan-cancer NGS testing that benefits patients into clinical practice.

NTRK fusion detection across multiple assays and 33,997 cases: diagnostic implications and pitfalls.

With the FDA approval of larotrectinib, NTRK fusion assessment has recently become a standard part of management for patients with locally advanced or metastatic cancers. Unlike somatic mutation assessment, the detection of NTRK fusions is not straightforward, and various assays exist at the DNA, RNA, and protein level. Here, we investigate the performance of immunohistochemistry and DNA-based next-generation sequencing to indirectly or directly detect NTRK fusions relative to an RNA-based next-generation sequencing approach in the largest cohort of NTRK fusion positive solid tumors to date. A retrospective analysis of 38,095 samples from 33,997 patients sequenced by a targeted DNA-based next-generation sequencing panel (MSK-IMPACT), 2189 of which were also examined by an RNA-based sequencing assay (MSK-Fusion), identified 87 patients with oncogenic NTRK1-3 fusions. All available institutional NTRK fusion positive cases were assessed by pan-Trk immunohistochemistry along with a cohort of control cases negative for NTRK fusions by next-generation sequencing. DNA-based sequencing showed an overall sensitivity and specificity of 81.1% and 99.9%, respectively, for the detection of NTRK fusions when compared to RNA-based sequencing. False negatives occurred when fusions involved breakpoints not covered by the assay. Immunohistochemistry showed overall sensitivity of 87.9% and specificity of 81.1%, with high sensitivity for NTRK1 (96%) and NTRK2 (100%) fusions and lower sensitivity for NTRK3 fusions (79%). Specificity was 100% for carcinomas of the colon, lung, thyroid, pancreas, and biliary tract. Decreased specificity was seen in breast and salivary gland carcinomas (82% and 52%, respectively), and positive staining was often seen in tumors with neural differentiation. Both sensitivity and specificity were poor in sarcomas. Selection of the appropriate assay for NTRK fusion detection therefore depends on tumor type and genes involved, as well as consideration of other factors such as available material, accessibility of various clinical assays, and whether comprehensive genomic testing is needed concurrently.

Plasma-thrombin cell blocks: Potential source of DNA contamination.

BACKGROUND: Cell blocks are being used more frequently in cytology for ancillary testing, including molecular diagnostics. There are several different methods of processing cell blocks, with plasma-thrombin being one of the most common. Plasma is a blood-derived product and may be a source of DNA. The aim of this study was to determine whether the plasma used for the plasma-thrombin cell block method has amplifiable DNA that may potentially interfere with molecular testing results. METHODS: Expired bags of fresh frozen plasma were collected from a blood bank. From each sample, DNA was extracted from a 1-mL aliquot with the QIAsymphony MIDI kit (Qiagen). The concentration of DNA was measured on a NanoDrop instrument. The amplifiable DNA quality was assessed by polymerase chain reaction (PCR) with primers to generate amplicons of various sizes. Characterization was performed with the AmpFLSTR Identifiler Plus PCR kit with capillary electrophoresis. RESULTS: Twenty samples from 20 bags were collected. All samples showed amplifiable DNA despite low DNA concentrations in a few cases. PCR amplification revealed the presence of high-quality amplifiable DNA (up to 600 base pairs). DNA was amplified at the 16 loci interrogated in all samples tested with the AmpFLSTR Identifiler Plus PCR kit. CONCLUSIONS: The presence of genomic DNA in plasma may theoretically interfere with results of molecular testing. Particularly in clinical samples with low cellularity, the DNA in plasma may potentially either mask the presence of minute amounts of tumor-derived DNA or lead to a false-positive result.

Current status of biomarker testing in historically rare, high-unmet-need tumors: soft tissue sarcomas and thyroid cancers.

Introduction: The development of precision medicine and targeted therapies have revolutionized cancer treatment. Historically, treatment was chosen based on the tumor-histology, but can now be tailored to patient-specific biomarkers. Investigations have shown up to 40% of cancer patients who undergo molecular testing have an actionable biomarker with a drug currently available, and that patients benefit from these drugs. In 2018, larotrectinib became the first drug developed and approved exclusively as a tumor-agnostic therapy. Because of advancement in precision medicine, biomarker testing has become a standard of care in a variety of tumors and its use is increasing.Areas covered: We discuss the landscape of biomarker testing in the context of soft tissue sarcomas and thyroid cancer, two rare diseases with historically high unmet needs in their subpopulations. We summarize historical data and contemporary applications.Expert opinion: The paradigm shift in oncology treatment toward precision medicine, including tumor-agnostic agents, is experiencing substantial momentum but still facing challenges. A gap exists between guideline recommendations for biomarker testing and clinical application, resulting in compromised access and suboptimal outcomes. Future progress will require routine access to testing and expanding treatment options coupled with awareness, predictability, and strategies to address resistance mechanisms.

Detection of Tumor NTRK Gene Fusions to Identify Patients Who May Benefit from Tyrosine Kinase (TRK) Inhibitor Therapy.

Chromosomal rearrangements involving the NTRK1, NTRK2, and NTRK3 genes (NTRK genes), which encode the high-affinity nerve growth factor receptor (TRKA), brain-derived neurotrophic factor/neurotrophin-3 (BDNF/NT-3) growth factor receptor (TRKB), and neurotrophin-3 (NT-3) growth factor receptor (TRKC) tyrosine kinases (TRK proteins), act as oncogenic drivers in a broad range of pediatric and adult tumor types. NTRK gene fusions have been shown to be actionable genomic events that are predictive of response to TRK kinase inhibitors, making their routine detection an evolving clinical priority. In certain exceedingly rare tumor types, NTRK gene fusions may be seen in the overwhelming majority of cases, whereas in a range of common cancers, reported incidences are in the range of 0.1% to 2%. Herein, we review the structure of the three NTRK genes and the nature and incidence of NTRK gene fusions in different solid tumor types, and we summarize the clinical data showing the importance of identifying tumors harboring such genomic events. We also outline the laboratory techniques that can be used to diagnose NTRK gene fusions in clinical samples. Finally, we propose a diagnostic algorithm for solid tumors to facilitate the identification of patients with TRK fusion cancer. This algorithm accounts for the widely varying frequencies by tumor histology and the underlying prevalence of TRK expression in the absence of NTRK gene fusions and is based on a combination of fluorescence in situ hybridization, next-generation sequencing, and immunohistochemistry assays.

Identification of a secondary RET mutation in a pediatric patient with relapsed acute myeloid leukemia leads to the diagnosis and treatment of asymptomatic metastatic medullary thyroid cancer in a parent: a case for sequencing the germline.

The incorporation of tumor-normal genomic testing into oncology can identify somatic mutations that inform therapeutic measures but also germline variants associated with unsuspected cancer predisposition. We describe a case in which a RET variant was identified in a 3-yr-old male with relapsed leukemia. Sanger sequencing revealed the patient's father and three siblings carried the same variant, associated with multiple endocrine neoplasia 2A (MEN2A). Evaluation of the father led to the diagnosis and treatment of metastatic medullary thyroid carcinoma. Detection of RET mutations in families with hereditary MTC allows for genetic risk stratification and disease surveillance to reduce morbidity and mortality.