A Comprehensive Meta-Analysis of Association between EGFR Mutation Status and Brain Metastases in NSCLC

Unique genomic alterations in the circulating tumor DNA of patients with solid tumors brain metastases

Background

Although serum circulating tumor DNA (ctDNA) is routine, data from patients with brain metastases (BrMs) is limited. We assessed genomic alterations in ctDNA from patients with solid tumor BrMs in 3 groups: Isolated BrMs with stable extracranial disease (iCNS), concurrent brain and extracranial progression (cCNS), and extracranial progression with no active BrMs (eCNS). We also compared ctDNA alterations between patients with and without BrMs.

Methods

Patients with a Guardant360 ctDNA profile with (n = 253) and without BrMs (n = 449) from the Duke Molecular Registry between January 2014 and December 2020 were identified. Actionable alterations were defined as FDA-recognized or standard-of-care biomarkers. Disease status was determined via investigator assessment within 30 days of ctDNA collection.

Results

Among the 253 patients with BrMs: 29 (12%) had iCNS, 160 (63%) cCNS, and 64 (25%) eCNS. Breast (BC; 12.0%) and non-small cell lung cancer (NSCLC; 76.4%) were the most common tumor types. ESR1 (60% vs 25%, P < .001) and BRCA2 (17% vs 5%, P = .022) were more frequent in BC BrMs. In NSCLC BrMs, EGFR alterations were most frequent in the iCNS group (iCNS: 67%, cCNS: 40%, eCNS:37%, P = .08) and in patients with BrMs (36% vs 17%, P < .001). Sequencing from both brain tissue and ctDNA were available for 8 patients; 7 (87.5%) had identical alterations.

Conclusions

This study illustrates the feasibility of detecting alterations from ctDNA among patients with BrMs. A higher frequency of actionable mutations was observed in ctDNA in patients with BrMs. Additional studies comparing ctDNA and alterations in BrMs tissue are needed to determine if ctDNA can be considered a surrogate to support treatment decisions.

Nitroglycerin Plus Whole Intracranial Radiation Therapy for Brain Metastases in Patients With Non-Small Cell Lung Cancer: A Randomized, Open-Label, Phase 2 Clinical Trial

PURPOSE

Hypoxia has been associated with chemoradioresistance secondary to vascular endothelial growth factor receptor induced by hypoxia-induced factor (HIF). Nitroglycerin (NTG) can reduce HIF-1 in tissues, and this may have antiangiogenic, proapoptotic, and antiefflux effects. Particularly, epidermal growth factor-mutated (EGFRm) tumor cell lines have been shown to overexpress both vascular endothelial growth factor and HIF. In this phase 2 study, we evaluated the effect of transdermal NTG plus whole brain radiation therapy (WBRT) in patients with non-small cell lung cancer (NSCLC) with brain metastases (BM).

METHODS

This was an open-label, phase 2 clinical trial with 96 patients with NSCLC and BM. Patients were randomized 1:1 to receive NTG plus WBRT (30 Gy in 10 fractions) or WBRT alone. The primary endpoint was intracranial objective response rate (iORR) evaluated 3 months posttreatment. NTG was administered using a transdermal 36-mg patch from Monday through Friday throughout WBRT administration (10 days). The protocol was retrospectively registered at ClinicalTrials.gov (NCT04338867).

RESULTS

Fifty patients were allocated to the control group, and 46 were allocated to the experimental group (NTG); among these, 26 (52%) had EGFRm in the control group and 21 (45.7%) had EGFRm in the NTG arm. In terms of the iORR, patients in the NTG group had a significantly higher response compared with controls (56.5% [n = 26/46 evaluable patients] vs 32.7% [n = 16/49 evaluable patients]; relative risk, 1.73; 95% confidence interval [CI], 1.08-2.78; P = .024). Additionally, patients who received NTG + WBRT had an independently prolonged intracranial progression-free survival (ICPFS) compared with those who received WBRT alone (27.7 vs 9.6; hazard ratio [HR], 0.5; 95% CI, 0.2-0.9; P = .020); this positively affected overall progression-free survival among patients who received systemic therapy (n = 88; HR, 0.5; 95% CI, 0.2-0.9; P = .043). The benefit of ICPFS (HR, 0.4; 95% CI, 0.2-0.9; P = .030) was significant in the EGFRm patient subgroup. No differences were observed in overall survival. A significantly higher rate of vomiting presented in the NTG arm of the study (P = .016).

CONCLUSIONS

The concurrent administration of NTG and radiation therapy improves iORR and ICPFS among patients with NSCLC with BM. The benefit in ICPFS is significant in the EGFRm patient subgroup.

Efficacy of immune checkpoint inhibitor therapy in EGFR mutation-positive patients with NSCLC and brain metastases who have failed EGFR-TKI therapy

Background

Few treatment options are available for brain metastases (BMs) in EGFR-mutant non-small cell lung cancer (NSCLC) that progress with prior EGFR tyrosine kinase inhibitor (EGFR-TKI) therapy. This study aimed to evaluate the efficacy of immune checkpoint inhibitor (ICI) therapy in these patients.

Methods

NSCLC patients with confirmed sensitive EGFR mutations and BMs were retrospectively reviewed. All patients experienced failure of EGFR-TKI therapy and were divided into two cohorts based on subsequent treatment. Cohort 1 included patients who received ICI therapy, while cohort 2 included patients treated with chemotherapy. Overall and intracranial objective response rates (ORRs) were used to evaluate the treatment response. Overall and intacranial progression-free survival (PFS) were calculated by Kaplan−Meier analysis and compared with the log-rank test. Univariate and multivariate Cox analyses were used to identify prognostic factors.

Results

A total of 53 patients treated with ICI therapy and 40 patients treated with chemotherapy were included in cohorts 1 and 2, respectively. In cohort 1, the overall ORR was 20.8%, with a median overall PFS of 4.2 months. The median intracranial PFS was 5.1 months. Of the 38 patients with measurable intracranial lesions, the intracranial ORR was 21.0%. Patients who received ICI combined with chemotherapy had the highest intracranial ORR of 37.5%. Compared to patients treated with chemotherapy in cohort 2, patients receiving ICI combined with chemotherapy had both longer intracranial PFS (6.4 vs. 5.1 months, p = 0.110) and overall PFS (6.2 vs. 4.6 months, p = 0.054), and these differences approached statistical significance. Univariate and multivariate Cox analyses demonstrated that high disease burden (p = 0.019), prior third-generation EGFR-TKI therapy (p = 0.019), and a poor lung immune prognostic index (LIPI) (p = 0.012) were independent negative predicators of overall PFS and that multiple BMs were negatively correlated with intracranial PFS among patients treated with ICI therapy.

Conclusions

Our results suggested that ICI combined with chemotherapy had potent intracranial efficacy and may be a promising treatment candidate in EGFR-mutant NSCLC patients with BMs for whom prior EGFR-TKI therapy failed.

Role of Pre-Operative Brain Imaging in Patients with NSCLC Stage I: A Retrospective, Multicenter Analysis

Simple Summary

Lung cancer is the worldwide leading cause of cancer-related death among both genders, with about 230,000 patients/year being diagnosed in the US alone. It accounts for about 40% of all brain metastases, which already occur in around 3% of early-stage patients. Nonetheless, current international guidelines do not unanimously recommend brain imaging for use in the early stages of cancer. Some studies have suggested that surgical or radiosurgical treatment of brain metastases may provide better survival, especially in asymptomatic patients. Additionally, advances in genome analysis have identified molecular targets for pharmaceutical agents. These recent advancements in treatment stress the importance of studying incidence as well as patient and tumor characteristics in order to potentially adapt future guidelines and provide the best possible treatment for early-stage lung cancer. This multicentric study analyzed the data of 577 patients diagnosed with early-stage lung cancer who had been submitted for brain imaging at initial tumor staging.

Abstract

Background: Lung cancer is the worldwide leading oncological cause of death in both genders combined and accounts for around 40–50% of brain metastases in general. In early-stage lung cancer, the incidence of brain metastases is around 3%. Since the early detection of asymptomatic cerebral metastases is of prognostic value, the aim of this study was to analyze the incidence of brain metastases in early-stage lung cancer and identify possible risk factors. Methods: We conducted a retrospective multicentric analysis of patients with Stage I (based on T and N stage only) Non-Small Cell Lung Cancer (NSCLC) who had received preoperative cerebral imaging in the form of contrast-enhanced CT or MRI. Patients with a history of NSCLC, synchronous malignancy, or neurological symptoms were excluded from the study. Analyzed variables were gender, age, tumor histology, cerebral imaging findings, smoking history, and tumor size. Results were expressed as mean with standard deviation or median with range. Results: In total, 577 patients were included in our study. Eight (1.4%) patients were found to have brain metastases in preoperative brain imaging. Tumor histology was adenocarcinoma in all eight cases. Patients were treated with radiotherapy (five), surgical resection (two), or both (one) prior to thoracic surgical treatment. Other than tumor histology, no statistically significant characteristics were found to be predictive of brain metastases. Conclusion: Given the low incidence of brain metastases in patients with clinical Stage I NSCLC, brain imaging in this cohort could be avoided.

A Need for More Molecular Profiling in Brain Metastases

As local disease control improves, the public health impact of brain metastases (BrM) continues to grow. Molecular features are frequently different between primary and metastatic tumors as a result of clonal evolution during neoplasm migration, selective pressures imposed by systemic treatments, and differences in the local microenvironment. However, biomarker information in BrM is not routinely obtained despite emerging evidence of its clinical value. We review evidence of discordance in clinically actionable biomarkers between primary tumors, extracranial metastases, and BrM. Although BrM biopsy/resection imposes clinical risks, these risks must be weighed against the potential benefits of assessing biomarkers in BrM. First, new treatment targets unique to a patient's BrM may be identified. Second, as BrM may occur late in a patient's disease course, resistance to initial targeted therapies and/or loss of previously identified biomarkers can occur by the time of occult BrM, rendering initial and other targeted therapies ineffective. Thus, current biomarker data can inform real-time treatment options. Third, biomarker information in BrM may provide useful prognostic information for patients. Appreciating the importance of biomarker analyses in BrM tissue, including how it may identify specific drivers of BrM, is critical for the development of more effective treatment strategies to improve outcomes for this growing patient population.

Cancer driver gene and non-coding RNA alterations as biomarkers of brain metastasis in lung cancer: A review of the literature

Brain metastasis (BM) is the most common event in patients with lung cancer. Despite multimodal treatments and advances in systemic therapies, development of BM remains one of the main factors associated with poor prognosis and mortality in patients with lung cancer. Therefore, better understanding of mechanisms involved in lung cancer brain metastasis (LCBM) is of great importance to suppress cancer cells and to improve the overall survival of patients. Several cancer-related genes such as EGFR and KRAS have been proposed as potential predictors of LCBM. In addition, there is ample evidence supporting crucial roles of non-coding RNAs (ncRNAs) in mediating LCBM. In this review, we provide comprehensive information on risk assessment, predictive, and prognostic panels for early detection of BM in patients with lung cancer. Moreover, we present an overview of LCBM molecular mechanisms, cancer driver genes, and ncRNAs which may predict the risk of BM in lung cancer patients. Recent clinical studies have focused on determining mechanisms involved in LCBM and their association with diagnosis, prognosis, and treatment outcomes. These studies have shown that alterations in EGFR, KRAS, BRAF, and ALK, as the most frequent coding gene alterations, and dysregulation of ncRNAs such as miR-423, miR-330-3p, miR-145, piR-651, and MALAT1 can be considered as potential biomarkers of LCBM.

E2F1-mediated repression of WNT5A expression promotes brain metastasis dependent on the ERK1/2 pathway in EGFR-mutant non-small cell lung cancer

Brain metastasis (BM) is associated with poor prognosis in patients with advanced non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) mutation reportedly enhances the development of BM. However, the exact mechanism of how EGFR-mutant NSCLC contributes to BM remains unknown. Herein, we found the protein WNT5A, was significantly downregulated in BM tissues and EGFR-mutant samples. In addition, the overexpression of WNT5A inhibited the growth, migration, and invasion of EGFR-mutant cells in vitro and retarded tumor growth and metastasis in vivo compared with the EGFR wide-type cells. We demonstrated a molecular mechanism whereby WNT5A be negatively regulated by transcription factor E2F1, and ERK1/2 inhibitor (U0126) suppressed E2F1's regulation of WNT5A expression in EGFR-mutant cells. Furthermore, WNT5A inhibited β-catenin activity and the transcriptional levels of its downstream genes in cancer progression. Our research revealed the role of WNT5A in NSCLC BM with EGFR mutation, and proved that E2F1-mediated repression of WNT5A was dependent on the ERK1/2 pathway, supporting the notion that targeting the ERK1/2-E2F1-WNT5A pathway could be an effective strategy for treating BM in EGFR-mutant NSCLC.

The mutational landscape of melanoma brain metastases presenting as the first visceral site of recurrence

Brain metastases are a major cause of melanoma-related mortality and morbidity. We undertook whole-exome sequencing of 50 tumours from patients undergoing surgical resection of brain metastases presenting as the first site of visceral disease spread and validated our findings in an independent dataset of 18 patients. Brain metastases had a similar driver mutational landscape to cutaneous melanomas in TCGA. However, KRAS was the most significantly enriched driver gene, with 4/50 (8%) of brain metastases harbouring non-synonymous mutations. Hotspot KRAS mutations were mutually exclusive from BRAFV600, NRAS and HRAS mutations and were associated with a reduced overall survival from the resection of brain metastases (HR 10.01, p = 0.001). Mutations in KRAS were clonal and concordant with extracranial disease, suggesting that these mutations are likely present within the primary. Our analyses suggest that KRAS mutations could help identify patients with primary melanoma at higher risk of brain metastases who may benefit from more intensive, protracted surveillance.