A multicenter study of thromboembolic events among patients diagnosed with ROS1-rearranged non-small cell lung cancer

Ambulatory cancer patients: who should definitely receive antithrombotic prophylaxis and who should never receive

Up to 15-20% of cancer patients experience one or more episodes of venous thromboembolism during cancer disease. Approximately 80% of all cancer-associated venous thromboembolic events occur in non-hospitalized patients. Routine thromboprophylaxis for outpatients with cancer who start new anticancer treatment is currently not recommended by the international guidelines due to the high heterogeneity of these patients in terms of VTE or bleeding risks, the difficulties in selecting patients at high risk, and the uncertainty of duration of prophylaxis. Although the international guidelines endorsed the Khorana score for estimating the thrombotic risk in ambulatory cancer patients, the discriminatory performance of this score is not completely convincing and varies according to the cancer type. Consequently, a minority of ambulatory patients with cancer receive an accurate screening for primary prophylaxis of VTE. The aim of this review is to provide support to physicians in identifying those ambulatory patients with cancer for whom thromboprophylaxis should be prescribed and those that should not be candidate to thromboprophylaxis. In absence of high bleeding risk, primary thromboprophylaxis should be recommended in patients with pancreatic cancer and, probably, in patients with lung cancer harboring ALK/ROS1 translocations. Patients with upper gastrointestinal cancers are at high risk of VTE, but a careful assessment of bleeding risk should be made before deciding on antithrombotic prophylaxis. Primary prevention of VTE is not recommended in cancer patients at increased risk of bleeding as patients with brain cancer, with moderate-to-severe thrombocytopenia or severe renal impairment.

Application of Machine Learning to the Prediction of Cancer-Associated Venous Thromboembolism

Venous thromboembolism (VTE) is a common and impactful complication of cancer. Several clinical prediction rules have been devised to estimate the risk of a thrombotic event in this patient population, however they are associated with limitations. We aimed to develop a predictive model of cancer-associated VTE using machine learning as a means to better integrate all available data, improve prediction accuracy and allow applicability regardless of timing for systemic therapy administration. A retrospective cohort was used to fit and validate the models, consisting of adult patients who had next generation sequencing performed on their solid tumor for the years 2014 to 2019. A deep learning survival model limited to demographic, cancer-specific, laboratory and pharmacological predictors was selected based on results from training data for 23,800 individuals and was evaluated on an internal validation set including 5,951 individuals, yielding a time-dependent concordance index of 0.72 (95% CI = 0.70-0.74) for the first 6 months of observation. Adapted models also performed well overall compared to the Khorana Score (KS) in two external cohorts of individuals starting systemic therapy; in an external validation set of 1,250 patients, the C-index was 0.71 (95% CI = 0.65-0.77) for the deep learning model vs 0.66 (95% CI = 0.59-0.72) for the KS and in a smaller external cohort of 358 patients the C-index was 0.59 (95% CI = 0.50-0.69) for the deep learning model vs 0.56 (95% CI = 0.48-0.64) for the KS. The proportions of patients accurately reclassified by the deep learning model were 25% and 26% respectively. In this large cohort of patients with a broad range of solid malignancies and at different phases of systemic therapy, the use of deep learning resulted in improved accuracy for VTE incidence predictions. Additional studies are needed to further assess the validity of this model.

Rare molecular subtypes of lung cancer

Oncogenes that occur in ≤5% of non-small-cell lung cancers have been defined as 'rare'; nonetheless, this frequency can correspond to a substantial number of patients diagnosed annually. Within rare oncogenes, less commonly identified alterations (such as HRAS, NRAS, RIT1, ARAF, RAF1 and MAP2K1 mutations, or ERBB family, LTK and RASGRF1 fusions) can share certain structural or oncogenic features with more commonly recognized alterations (such as KRAS, BRAF, MET and ERBB family mutations, or ALK, RET and ROS1 fusions). Over the past 5 years, a surge in the identification of rare-oncogene-driven lung cancers has challenged the boundaries of traditional clinical grade diagnostic assays and profiling algorithms. In tandem, the number of approved targeted therapies for patients with rare molecular subtypes of lung cancer has risen dramatically. Rational drug design has iteratively improved the quality of small-molecule therapeutic agents and introduced a wave of antibody-based therapeutics, expanding the list of actionable de novo and resistance alterations in lung cancer. Getting additional molecularly tailored therapeutics approved for rare-oncogene-driven lung cancers in a larger range of countries will require ongoing stakeholder cooperation. Patient advocates, health-care agencies, investigators and companies with an interest in diagnostics, therapeutics and real-world evidence have already taken steps to surmount the challenges associated with research into low-frequency drivers.

Risk of thromboembolism in non-small-cell lung cancers patients with different oncogenic drivers, including ROS1, ALK, and EGFR mutations

BACKGROUND

Anaplastic lymphoma kinase-positive (ALK+) and ROS proto-oncogene 1 (ROS1)-positive (ROS1+) lung cancers have been reported to be associated with an elevated risk of thromboembolic events. This study aimed to assess the long-term risk of developing thromboembolism (TE) in ROS1+ lung cancer and to compare it with other oncogenic drivers in the Asian population.

MATERIALS AND METHODS

We retrospectively enrolled a cohort of ROS1+ lung adenocarcinoma in a medical center in Taiwan and a comparison cohort of ALK+ and epidermal growth factor receptor-positive (EGFR+) lung cancers. Venous and arterial TEs were identified throughout the cancer course, and the incidence rate was calculated.

RESULTS

We enrolled 44 ROS1+, 98 ALK+, and 168 EGFR+ non-small-cell lung cancer (NSCLC) patients. A total of 11 (25%), 36 (36.7%), and 38 (22.6%) patients in the ROS1, ALK, and EGFR cohorts, respectively, were diagnosed with thromboembolic events throughout the follow-up course of the disease (P = 0.042). The incidence rates were 99.0, 91.9, and 82.5 events per 1000 person-years for the ROS1, ALK, and EGFR cohorts, respectively. The majority of thrombosis events in the ROS1 (91.6%) and ALK (85.4%) cohorts were venous. On the contrary, 43.2% of thromboembolic events were arterial in the EGFR cohort. A higher proportion of thromboembolic events were noted during cancer diagnosis in the ROS1 cohort (36.3%) than in the ALK (16.7%) and EGFR (10.5%) cohorts. The stage was the only clinical variable associated with thromboembolic risk. There was a significant difference in survival between patients with and without TE in the EGFR cohort, but not in the ALK and ROS1 cohorts.

CONCLUSIONS

Although ROS1+ and ALK+ NSCLCs had a higher cumulative incidence of TE than EGFR+ NSCLC, the person-year incidence rates were similar among the three groups. EGFR-mutated NSCLC had more arterial events. Nevertheless, ALK+ lung cancer had higher venous events than EGFR-mutated lung cancer.

Common genetic driver mutation in NSCLC and their association with thromboembolic events: A retrospective study

This retrospective study aimed to estimate the incidence, risk factors of thromboembolism events (TEs) in non-small cell lung cancer patients harboring common gene mutation, and evaluate a genetic link between oncogenes and the risk of TEs in Asian patients with NSCLC.

METHODS

Univariate and multivariate Cox's proportional hazards regression models were used to identify the strongest predictors of TE development and evaluate the risk of TE in patients with different gene statuses of NSCLC patients.

RESULTS

In univariate and multivariate COX analysis, patient with squamous cell carcinoma (HR 3.01, 95% CI: [1.06,8.56]; p = 0.039), multi-site metastases (HR: 2.72; 95% CI: [1.08,6.92]; p = 0.032) or high white blood cell (WBC) (HR 3.24, 95% CI: [1.46,7.22]; p = 0.004), less hemoglobin (HGB) (HR 4.89, 95% CI: [1.90,12.64]; p = 0.001), are at higher risk of thrombosis. At the molecular level, ROS and ALK rearrangement is highly associated with TE development, with HR of 4.04 (95%CI: [1.54,10.58]; p = 0.005) and HR of 3.57 (95% CI: [1.01,12.66]; p = 0.049) in univariate analysis, and even higher in multivariate analysis. EGFR mutations seem to be a protective factor against TE in univariate analyses (HR:0.28, 95%CI [0.12,0.65], p = 0.003) but are not statistically significant in the multivariate model. No correlation between KRAS mutations and TE events in both models. Besides, a numerically higher cumulative incidence of thrombosis event was observed in patients who used TKI (HR 1.473; 95% CI: [0.682, 3.181]; p = 0.32).

CONCLUSION

Our study demonstrated that driver gene mutation may increase the risk of thrombosis in non-small cell lung cancer patients. The presence of ALK/ROS rearrangements in our study is associated with an approximately threefold to fourfold increase in thrombosis risk in NSCLC patients. For advanced-stage patients who used TKI, an increased incidence of thrombosis risk and shorter follow-up were observed.

The association between ROS1 rearrangement and risk of thromboembolic events in patients with advanced non-small cell lung cancer: a multicenter study in China

Background

According to several studies, ROS1 rearrangement is associated with thrombotic risk in non-small cell lung cancer (NSCLC). However, there is no clear understanding of the predictors and prognostic impact of thromboembolic events (TEEs) in patients with advanced ROS1 rearrangement NSCLC.

Methods

A total of 47 newly diagnosed advanced NSCLC patients with ROS1 rearrangement from four Chinese hospitals were retrospectively included and were evaluated for TEEs incidence, characteristics, predictors, as well as response to therapies and overall survival (OS).

Results

Of the 47 enrolled patients, 23.4% (n = 11) patients developed TEEs. Among them, 7 of 11 patients (64%) developed pulmonary embolism (PE), and 5 patients (45%) experienced recurrent TEEs. In multivariate analysis, D-dimer was associated with the occurrence of TEEs in ROS1 rearranged NSCLC (HR 1.16, 95% CI 1.08–1.23, P < 0.001). Median progression-free survival (PFS) after first-line ROS1 tyrosine kinase inhibitors (TKIs) therapy was significantly longer in patients without TEEs than in those developing TEEs (26 months vs. 12 months, P = 0.0383). Furthermore, patients with TEEs had a shorter OS period than those without TEEs (29.8 months vs. not estimable, P = 0.0647).

Conclusion

The results of this multicenter study indicated that advanced NSCLC patients with ROS1 rearrangement were more likely to experience PE and TEEs recurrence. And patients with TEEs tended to have a worse prognosis. Furthermore, an elevated D-dimer level suggested a hypercoagulable state in NSCLC patients with ROS1 rearrangement.

Consensus on prevention and treatment of cancer-associated thrombosis (CAT) in controversial clinical situations with low levels of evidence

BACKGROUND

Cancer patients suffer high risk of venous thromboembolism (VTE). Cancer-associated VTE (CAT) causes hospitalization, morbidity, delayed cancer treatment, and mortality; therefore, exceptional CAT prevention and management are imperative.

METHODS

This review offers practical recommendations and treatment algorithms for eight complex, clinically relevant situations posing great uncertainty regarding management and requiring an urgent decision: VTE prophylaxis in ambulatory cancer patients with pancreatic pancreas (1) or lung cancer with molecular alterations (2); optimal management of VTE during antineoplastic treatment with antiangiogenics (3) or chemotherapy (4); protracted VTE treatment, determinants; (5) drugs used (6), and optimal VTE management in situations of high bleeding risk (7) or recurrent VTE (8).

RESULTS

With the evidence available, primary thromboprophylaxis in patients with lung cancer harbouring ALK/ROS1 translocations or pancreatic cancer receiving ambulatory chemotherapy must be appraised. If antiangiogenic therapy can yield a clear benefit and the patient recovers from a grade 3 thrombotic event, it can be cautiously re-introduced in selected cases, provided that the person agrees to assume the risk after being duly informed. Anticoagulation maintenance beyond 6 months is recommended in individuals with metastatic tumours, on active treatment, or at high risk for recurrent VTE without bleeding risk. In such cases, LMWH and DOACs are safe, being mindful that the latter could entail a higher risk of bleeding; consequently, they should be used judiciously in more haemorrhagic tumours, such as gastrointestinal cancers. In cases of recurrent VTE, the presence of active cancer, infra-therapeutic dose, and anticoagulant treatment failure must be ruled out. In individuals with platelet counts of 25,000-50,000 and VTE liable to recur who need anticoagulation, full-dose LMWH and transfusion support can be contemplated to reach values of > 50,000. In CAT unlikely to recur, decreasing the LMWH dose by 25-50% is recommended. Renal impairment associated with thrombosis must be treated with LMWHs; there is no need to adjust the dose in patients with CrCl > 30; with CrCl = 15-30, dose adjustment is advised, and suspended when CrCl is < 15.

CONCLUSION

We provide useful advice for complex, clinically relevant situations that clinicians treating CAT must face devoid of any unequivocal, strong, evidence-based recommendations.

Association of anticoagulant use with clinical outcomes from crizotinib in ALK- and ROS1-rearranged advanced non-small cell lung cancers: A retrospective analysis of PROFILE 1001

BACKGROUND

ROS1- and ALK-rearranged advanced NSCLCs are associated with increased thromboembolic risk. We hypothesized that a prothrombotic phenotype offers an evolutionary advantage to subsets of these cancers. The impact of this phenotype could alter outcomes from targeted therapy.

METHODS

In a retrospective analysis of ROS1- and ALK-rearranged NSCLCs treated with crizotinib in a phase 1 trial, we compared progression-free survival (PFS) and objective response rate (ORR) based on the history of anticoagulation use (a possible surrogate of thromboembolism) at baseline (within 90 days before study enrollment) or within 90 days of study treatment.

RESULTS

Twelve out of 53 (22.6%) ROS1- and 39 out of 153 (25.5%) ALK-rearranged NSCLCs received anticoagulation before or during the trial. Most ROS1 and ALK patients on anticoagulation received low-molecular-weight heparin (75% and 64.1%, respectively). In the ROS1-rearranged group, the median PFS (95% CI) values were 5.1 (4.4-14.4) and 29.0 (16.5-48.8) months, and the ORR values were 41.7% (95% CI: 15.2 to 72.3) and 80.5% (95% CI: 65.1 to 91.2) among those with and without anticoagulation treatment, respectively. In the ALK-rearranged group, the median PFS (95% CI) was 7.1 (5.4-7.7) and 12.0 (9.4-18.3) months, and the ORR was 41% (95% CI: 25.6 to 57.9) and 74.3% (95% CI: 65.3 to 82.1) among those with and without anticoagulation, respectively.

CONCLUSIONS

Anticoagulation (as a potential surrogate of a prothrombotic subset) in ROS1- and ALK-rearranged NSCLCs may be associated with a lower PFS and ORR to crizotinib.

CLINICALTRIAL

gov: NCT00585195.

Cancer-associated venous thromboembolism

Cancer-associated thrombosis (including venous thromboembolism (VTE) and arterial events) is highly consequential for patients with cancer and is associated with worsened survival. Despite substantial improvements in cancer treatment, the risk of VTE has increased in recent years; VTE rates additionally depend on the type of cancer (with pancreas, stomach and primary brain tumours having the highest risk) as well as on individual patient's and cancer treatment factors. Multiple cancer-specific mechanisms of VTE have been identified and can be classified as mechanisms in which the tumour expresses proteins that alter host systems, such as levels of platelets and leukocytes, and in which the tumour expresses procoagulant proteins released into the circulation that directly activate the coagulation cascade or platelets, such as tissue factor and podoplanin, respectively. As signs and symptoms of VTE may be non-specific, diagnosis requires clinical assessment, evaluation of pre-test probability, and objective diagnostic testing with ultrasonography or CT. Risk assessment tools have been validated to identify patients at risk of VTE. Primary prevention of VTE (thromboprophylaxis) has long been recommended in the inpatient and post-surgical settings, and is now an option in the outpatient setting for individuals with high-risk cancer. Anticoagulant therapy is the cornerstone of therapy, with low molecular weight heparin or newer options such as direct oral anticoagulants. Personalized treatment incorporating risk of bleeding and patient preferences is essential, especially as a diagnosis of VTE is often considered by patients even more distressing than their cancer diagnosis, and can severely affect the quality of life. Future research should focus on current knowledge gaps including optimizing risk assessment tools, biomarker discovery, next-generation anticoagulant development and implementation science.

Deepening the Knowledge of ROS1 Rearrangements in Non-Small Cell Lung Cancer: Diagnosis, Treatment, Resistance and Concomitant Alterations

ROS proto-oncogene 1 (ROS1) rearrangements are reported in about 1-2% of non-squamous non-small-cell lung cancer (NSCLC). After efficacy of crizotinib was demonstrated, identification of ROS1 translocations in advanced disease became fundamental to give patients the chance of specific and effective treatment. Different methods are available for detection of rearrangements, and probably the real prevalence of ROS1 rearrangements is higher than that reported in literature, as our capacity to detect gene rearrangements is improving. In particular, with next generation sequencing (NGS) techniques, we are currently able to assess multiple genes simultaneously with increasing sensitivity. This is leading to overcome the "single oncogenic driver" paradigm, and in the very near future, the co-existence of multiple drivers will probably emerge more frequently and represent a therapeutic issue. Since recently, crizotinib has been the only available therapy, but today, many other tyrosine kinase inhibitors (TKI) are emerging and seem promising both in first and subsequent lines of treatment. Indeed, novel inhibitors are also able to overcome resistance mutations to crizotinib, hypothesizing a possible sequential strategy also in ROS1-rearranged disease. In this review, we will focus on ROS1 rearrangements, dealing with diagnostic aspects, new therapeutic options, resistance issues and the coexistence of ROS1 translocations with other molecular alterations.

Thromboembolism in ALK+ and ROS1+ NSCLC patients: A systematic review and meta-analysis

INTRODUCTION

Increased thromboembolism (TE) has been reported in ALK+ and ROS1+ non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Odds ratios (OR) and hazard ratios (HR) of TE were calculated from meta-analysis and time-to-event analysis respectively for either ALK+ or ROS1+ NSCLC patients.

RESULTS

We identified eight studies (766 ALK+, 143 ROS1+, 2314 non-ALK+ and non-ROS1+ NSCLC patients) for the meta-analysis. For ALK+ NSCLC, the pooled OR was 2.00 (95% CI: 1.60-2.50) for total TE (TTE) by random-effects model, 2.10 (95% CI: 1.70-2.60) for venous thromboembolism (VTE), and 1.24 (95% CI: 0.80-1.91) for arterial thromboembolism (ATE). For ROS1+ NSCLC, the pooled OR was 3.08 (95% CI: 1.95-4.86) for TTE, and 3.15 (95% CI: 1.83-5.43) for VTE. Six studies (739 ALK+, 137 ROS1+, 561 EGFR+, 714 "wildtype" NSCLC patients) were included in the time-to-event analysis. The TTE incidence rate was 17.4 (95% CI: 15.3-19.5) per 100 pateint-years for ALK+ NSCLC, and 32.1 (95% CI: 24.6-39.6) per 100 patient-years for ROS1+ NSCLC with a 50 % cumulative incidence rate at year 3 of diagnosis. HR for TTE was 2.35 (95% CI: 1.90-2.92, p < 0.001) and 3.23 (95% CI: 2.40-4.34, p < 0.001) for ALK+ and ROS1+ NSCLC, respectively. Comparing ROS1+ NSCLC to ALK+ NSCLC, HR for TTE was 1.37 (95% CI: 1.05-1.79, p = 0.020).

CONCLUSIONS

ALK+ and ROS1+ NSCLC patients had an increased risk of TE. ROS1+ NSCLC had further increased risk of TE over ALK+ NSCLC.

Screening for ROS1 fusions in patients with advanced non-small cell lung carcinomas using the VENTANA ROS1 (SP384) Rabbit Monoclonal Primary Antibody

Introduction: The development of several ROS1 inhibitors means that the importance of accurately identifying ROS1-positive lung cancer patients has never been greater. Therefore, it is crucial that ROS1 testing assays become more standardized.Areas covered: Based on primary literature, combined with personal diagnostic and research experience, this review provide a pragmatic update on the use of the recently released VENTANA ROS1 (SP384) Rabbit Monoclonal Primary Antibody.Expert opinion: This assay provides high sensitivity, so it is an excellent analytical option when screening for ROS1 fusions in patients with advanced non-small cell lung carcinomas.

Driver Genes Associated With the Incidence of Venous Thromboembolism in Patients With Non-Small-Cell Lung Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

The association between driver genes and the incidence of thromboembolic events (TEs) in patients diagnosed with non-small-cell lung cancer (NSCLC) needs to be quantified to guide clinical management.

METHODS

We interrogated PubMed, Embase, Web of Science and Cochrane library databases for terms related to venous thromboembolism (VTE) and arterial thromboembolism (ATE) in patients diagnosed with non-small-cell lung cancer harboring driver genes. This search was conducted for studies published between 1 January, 2000 and 31 December, 2020. A random-effects meta-analysis was performed to analyze the pooled incidence and odds ratios of VTE in patients with different driver genes.

RESULTS

Of the 2,742 citations identified, a total of 25 studies that included 21,156 patients met eligibility criteria. The overall pooled incidence of VTE in patients with driver genes was 23% (95% CI 18-29). Patients with ROS1 rearrangements had the highest incidence of VTE (37%, 95%CI 23-52). ALK rearrangements were associated with increased VTE risks (OR=2.08,95% CI 1.69-2.55), with the second highest incidence of VTE (27%, 95%CI 20-35). Both groups of patients with EGFR and KRAS mutations did not show a significantly increased risk for VTE (OR=1.33, 95% CI 0.75-2.34; OR=1.31, 95% CI 0.40-4.28).

CONCLUSIONS

ALK rearrangements were shown to be associated with increased VTE risks in patients diagnosed with non-small lung cancer, while there was no significant relation observed between VTE risks and EGFR or KRAS mutations in lung cancer patients.

Current treatment and future challenges in ROS1- and ALK-rearranged advanced non-small cell lung cancer

Non─small cell lung cancer (NSCLC) presents different druggable genetic abnormalities, including ROS1 and ALK rearrangements, which share relevant clinical features and therapeutic strategies. The homology between the tyrosine kinase domains of ROS1 and ALK defines unique subsets of patients highly sensitive to targeted tyrosine kinase inhibitors (TKIs). Genomic profiling in advanced NSCLC is standard, immunohistochemistry and fluorescence in situ hybridization being the main techniques used to detect genomic rearrangements. Personalized treatment with TKIs in ROS1- and ALK-positive NSCLC patients has dramatically improved patients' outcomes. Crizotinib has been the first-line standard of care treatment in ALK-rearranged NSCLC patients for a long time, while crizotinib still represents the best upfront therapeutic option in ROS1-positive NSCLC patients, followed by next-generation TKIs at the time of disease progression. However, the improved intracranial efficacy of next-generation TKIs has led to these drugs becoming first-line options, widening treatment opportunities for these patients. Since all patients will develop disease progression under TKI therapy, understanding the mechanisms of acquired resistance is crucial to define the optimal sequential therapeutic strategy. Despite the positive correlation between personalized treatment and patients' outcome, access to next-generation TKIs and genomic profiling at the time of disease progression are major challenges to achieving this goal. In this review, we present updated evidence on ROS1- and ALK-rearranged NSCLC regarding epidemiology and diagnostics, current therapies and the most suitable sequential treatment approaches, as well as mechanisms of acquired resistance and strategies to overcome them.

High discrepancy in thrombotic events in non-small cell lung cancer patients with different genomic alterations

Background

Acute complications, such as venous thromboembolism (VTE), are common in patients with advanced severe lung cancers. However, current VTE risk scores cannot adequately identify high-risk patients with non-small cell lung cancer (NSCLC). The study proposed to elucidated the incidence of thromboembolism (TE) in patients with different oncogenic aberrations and the impact of these aberrations on the efficacy of targeted therapy in patients with NSCLC.

Methods

A systemic review was conducted in Web of Science, PubMed, Embase and the Cochrane Library to evaluate the incidence of TE in different molecular subtypes of NSCLC. Data from patients diagnosed of advanced NSCLC who harboring anaplastic lymphoma kinase (ALK) or ROS proto-oncogene 1 receptor tyrosine kinase (ROS1) rearrangements since 2016 to 2019 were also retrospectively collected. A meta-analysis with random-effects model, sensitivity analysis and publication bias were performed. The principal summary measure was incidence of thrombotic events in NSCLC patients. And the efficacy of tyrosine kinase inhibitor (TKI) therapy was compared between the two subgroups.

Results

A total of 5,767 cases from 20 studies were included in the analysis of the incidence of thrombosis in patients with different oncogenic alterations. The pooled analysis showed a higher risk of thrombosis in ROS1-fusion types (41%, 95% CI: 35-47%) and ALK-fusion types (30%, 95% CI: 24-37%) than in EGFR-mutation (12%, 95% CI: 8-17%), KRAS-mutation (25%, 95% CI: 13-50%), and wild-type (14%, 95% CI: 10-20%) cases. A high prevalence of thrombosis (ALK: 24.4%; ROS1: 32.6%) was observed in the Shanghai Pulmonary Hospital (SPH) cohort of 224 patients with ALK or ROS1 fusion. Furthermore, patients with embolism had significantly shorter progression-free survival (PFS) after TKI therapy than those without embolism, both in the ALK+ cohort (5.6 vs. 12.9 months, P<0.0001) and in the ROS1+ cohort (9.6 vs. 17.6 months, P=0.0481).

Conclusions

NSCLC patients with ALK/ROS1 rearrangements are more likely to develop thrombosis than patients with other oncogenic alterations. Thrombosis may also be associated with an inferior response and PFS after TKI therapy.

The Road Less Traveled: A Guide to Metastatic ROS1-Rearranged Non-Small-Cell Lung Cancer

Over the past decade, significant advances have been achieved in the diagnostic testing, treatment, and prognosis of advanced non-small-cell lung cancer (NSCLC). One of the most significant developments was the identification of specific gene alterations that define subsets of NSCLC. In 2007, ROS1 rearrangements were first described and observed in approximately 1%-2% of patients with NSCLC. Currently, crizotinib remains the therapy of choice for advanced ROS1-rearranged NSCLC without CNS metastases, while entrectinib has emerged as the preferred option for those with CNS metastases. The next-generation inhibitors under development are more potent, have better CNS efficacy, and can overcome important resistance mutations. In this review, we focus on the management of patients with advanced NSCLC harboring a ROS1 rearrangement. We aim to provide insight into the diagnosis, treatment approach, and emerging treatments in this subgroup of NSCLC.

A Catalog of 5' Fusion Partners in ROS1-Positive NSCLC Circa 2020

ROS1 fusion-positive (ROS1+) NSCLC was discovered in 2007, the same year as the discovery of ALK-positive (ALK+) NSCLC but has trailed ALK+ NSCLC in terms of development. There seems to be a differential response to ROS1 inhibitors, which depend on fusion partners (CD74, SLC34A2, or SDC4); thus, knowledge of the fusion partners in ROS1+ NSCLC is important. To date (end of February 2020), we have identified 24 unique 5' fusion partners of ROS1 in ROS1+ NSCLC from published literature and congress proceedings. Thus, we published this catalog for easy reference.

ROS1-dependent cancers - biology, diagnostics and therapeutics

The proto-oncogene ROS1 encodes a receptor tyrosine kinase with an unknown physiological role in humans. Somatic chromosomal fusions involving ROS1 produce chimeric oncoproteins that drive a diverse range of cancers in adult and paediatric patients. ROS1-directed tyrosine kinase inhibitors (TKIs) are therapeutically active against these cancers, although only early-generation multikinase inhibitors have been granted regulatory approval, specifically for the treatment of ROS1 fusion-positive non-small-cell lung cancers; histology-agnostic approvals have yet to be granted. Intrinsic or extrinsic mechanisms of resistance to ROS1 TKIs can emerge in patients. Potential factors that influence resistance acquisition include the subcellular localization of the particular ROS1 oncoprotein and the TKI properties such as the preferential kinase conformation engaged and the spectrum of targets beyond ROS1. Importantly, the polyclonal nature of resistance remains underexplored. Higher-affinity next-generation ROS1 TKIs developed to have improved intracranial activity and to mitigate ROS1-intrinsic resistance mechanisms have demonstrated clinical efficacy in these regards, thus highlighting the utility of sequential ROS1 TKI therapy. Selective ROS1 inhibitors have yet to be developed, and thus the specific adverse effects of ROS1 inhibition cannot be deconvoluted from the toxicity profiles of the available multikinase inhibitors. Herein, we discuss the non-malignant and malignant biology of ROS1, the diagnostic challenges that ROS1 fusions present and the strategies to target ROS1 fusion proteins in both treatment-naive and acquired-resistance settings.

Lung Adenocarcinoma Presenting as Multiple Thromboembolic Events: A Case Report and Review of the Literature

Patients with malignancy may present with significant thromboembolic complications including deep vein thrombosis (DVT), pulmonary embolism, arterial thrombosis, nonbacterial thrombotic endocarditis, and stroke due to abnormal coagulation cascades. Although these events are typically recognized later in the disease process, complications of a hypercoagulable state can rarely present as the first manifestation of an occult malignancy. We report a case of a young male who was ultimately found to have an aggressive form of lung adenocarcinoma after the initial presentation of multiple thromboembolic events. DVT and stroke as an initial presentation of an active lung adenocarcinoma in a young patient is extremely rare as patients presenting in a hypercoagulable state usually are older. Though testing for a hypercoagulable state is not recommended for the first unprovoked DVT, clinicians should be prompted to screen for malignancy in the setting of cryptogenic strokes, especially in younger patients with no prior risk factors.