Brain metastasis features and association with tumor epidermal growth factor receptor mutation in patients with adenocarcinoma of the lung

State-of-the-Art Molecular Oncology of Lung Cancer in Taiwan

Lung cancers are life-threatening malignancies that cause great healthcare burdens in Taiwan and worldwide. The 5-year survival rate for Taiwanese patients with lung cancer is approximately 29%, an unsatisfactorily low number that remains to be improved. We first reviewed the molecular epidemiology derived from a deep proteogenomic resource in Taiwan. The nuclear factor erythroid 2-related factor 2 (NRF2)antioxidant mechanism was discovered to mediate the oncogenesis and tumor progression of lung adenocarcinoma. Additionally, DNA replication, glycolysis and stress response are positively associated with tumor stages, while cell-to-cell communication, signaling, integrin, G protein coupled receptors, ion channels and adaptive immunity are negatively associated with tumor stages. Three patient subgroups were discovered based on the clustering analysis of protein abundance in tumors. The first subgroup is associated with more advanced cancer stages and visceral pleural invasion, as well as higher mutation burdens. The second subgroup is associated with EGFR L858R mutations. The third subgroup is associated with PI3K/AKT pathways and cell cycles. Both EGFR and PI3K/AKT signaling pathways have been shown to induce NRF2 activation and tumor cell proliferation. We also reviewed the clinical evidence of patient outcomes in Taiwan given various approved targeted therapies, such as EGFR-tyrosine kinase inhibitors and anaplastic lymphoma kinase (ALK)inhibitors, in accordance with the patients’ characteristics. Somatic mutations occurred in EGFR, KRAS, HER2 and BRAF genes, and these mutations have been detected in 55.7%, 5.2%, 2.0% and 0.7% patients, respectively. The EGFR mutation is the most prevalent targetable mutation in Taiwan. EML4-ALK translocations have been found in 9.8% of patients with wild-type EGFR. The molecular profiling of advanced NSCLC is critical to optimal therapeutic decision-making. The patient characteristics, such as mutation profiles, protein expression profiles, drug-resistance profiles, molecular oncogenic mechanisms and patient subgroup systems together offer new strategies for personalized treatments and patient care.

Experimental Study of Almonertinib Crossing the Blood-Brain Barrier in EGFR-Mutant NSCLC Brain Metastasis and Spinal Cord Metastasis Models

Roughly one third of non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI)-sensitive mutated (EGFRm) tumors experience disease progression through central nervous system (CNS) metastases during treatment. Although EGFR-TKIs have been reported to be favored in some patients with EGFRm NSCLC CNS metastases, novel EGFR-TKIs with proven efficacy in CNS pathologies are clinically needed.To investigate whether almonertinib, a novel third-generation EGFR-TKI for NSCLC, can cross the blood-brain barrier (BBB) and deliver treatment for EGFR-mutant NSCLC brain metastases and spinal cord metastases, we constructed NSCLC brain metastasis and spinal cord metastasis models in vivo to observe the anti-tumor effects of almonertinib. Using ABCB1-MDCK and BCRP-MDCK monolayer cells as the in vitro study model, the effects of transport time and drug concentration on the apparent permeability coefficient of almonertinib and its active metabolite, HAS-719, were investigated. The results of this study show that almonertinib can significantly inhibit PC9 brain and spinal cord metastases. Pharmacokinetic studies in mice revealed that almonertinib has good BBB penetration ability, whereas the metabolite HAS-719 does not easily penetrate the BBB. Early clinical evidence of almonertinib activity in patients with EGFRm-advanced NSCLC and brain metastases has also been reported. In conclusion, almonertinib easily penetrates the BBB and inhibits advanced NSCLC brain and spinal cord metastases.

Effects of different brain surveillance strategies on outcomes for patients with EGFR-mutant metastatic lung adenocarcinoma under targeted therapy

OBJECTIVES

Brain metastasis (BM) is common in patients with epidermal growth factor receptor (EGFR)-mutant lung cancer. However, the brain surveillance strategy during treatment in advanced lung cancer patients varies, and the impact on clinical outcome is unclear. Here we aimed to evaluate the effect of different brain surveillance strategies on the clinical characteristics and treatment outcome in patients with EGFR-mutant lung adenocarcinoma treated with first-line EGFR tyrosine kinase inhibitors (EGFR-TKIs).

MATERIALS AND METHODS

This is a retrospective observational study conducted in a medical center in an area with high prevalence of EGFR mutation. Patients with initially diagnosed stage IV EGFR-mutant lung adenocarcinoma were included. Patients undergoing regular brain magnetic resonance imaging (MRI) every 3-6 months were categorized in the regular follow-up (RFU) group, and the rest were categorized in the liberal follow-up (LFU) group. Clinical outcomes were collected and analyzed.

RESULTS

A total of 310 patients were included, and 43.5% initially had brain metastases. Patients in the LFU group were significantly older than those in the RFU group (median age: 67 vs 62, p < 0.001). The overall survival and time-to-treatment failure of patients with initial EGFR-TKIs treatment showed no statistical difference between the two groups. However, the intracranial progression free survival was significantly shorter in the RFU group than in the LFU group (p = 0.009). The risk of mortality was similar in the LFU and RFU groups. There was no difference in the intracranial progression patterns and cause of death between the two groups.

CONCLUSIONS

For EGFR-mutant lung adenocarcinoma patients who used EGFR-TKIs as the frontline therapy, regular or liberal brain MRI follow-up showed no significant impact on the outcome, irrespective of initial brain metastasis.

[Prognostic Analysis of EGFR-TKIs Combined with Gamma Knife in EGFR-mutant Lung Adenocarcinoma with Brain Metastasis]

背景与目的

晚期表皮生长因子受体（epidermal growth factor receptor, EGFR）基因突变的肺腺癌在初诊或治疗过程中脑转移的总发生率高，局部治疗联合系统性靶向治疗可能是更佳策略。本研究拟探讨分析EGFR酪氨酸激酶抑制剂（tyrosine kinase inhibitors, TKIs）联合头颅伽玛刀治疗EGFR突变的肺腺癌伴脑转移患者的疗效及预后因素。

方法

回顾性收集EGFR基因突变的肺腺癌、在初诊即存在脑转移或在EGFR-TKIs治疗过程中肺部病灶稳定而出现脑转移、接受一线口服EGFR-TKIs靶向治疗联合脑部伽玛刀局部治疗的患者，评价EGFR-TKIs联合头颅伽马刀治疗对颅内病灶的疗效，随访并分析颅内无进展生存时间（intracranial progression free survival, i-PFS），探索EGFR突变肺腺癌伴脑转移的预后因素。

结果

共纳入74例患者，其中位i-PFS为14.7个月，1年无颅内进展率为58.5%，2年无颅内进展率为22.2%。颅内病灶与肺部病灶具有相近的进展时间。单因素生存分析显示，初诊癌胚抗原（carcinoembryonic antigen, CEA）水平 < 10 ng/mL（16.9个月vs 12.6个月，P=0.012）、颅内病灶长径 < 2 cm（15.4个月vs 10.8个月，P=0.021）、肺癌脑转移分级预后系统（lung graded prognostic assessment, Lung-molGPA）评分 > 3（15个月vs 12.6个月，P=0.041）的患者具有更长的i-PFS。多因素分析显示初诊时CEA≥10 ng/mL和颅内病灶≥2 cm是i-PFS的不良预后因素。

结论

EGFR-TKIs联合伽玛刀局部治疗对EGFR突变肺腺癌伴脑转移患者的颅内病灶具有良好的疗效。初诊时CEA水平≥10 ng/mL、颅内病灶≥2 cm是接受EGFR-TKIs联合伽马刀治疗的脑转移肺腺癌患者的不良预后因素。

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

Non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutation have different clinicopathological characteristics compared with EGFR wild type NSCLC. A growing number of studies focused on the relevance between EGFR mutation status and brain metastases (BM) in NSCLC, but it remains controversial. Therefore, this study performed a comprehensive meta-analysis to untangle this issue. Several electronic databases including Pubmed, Embase, Web of science and Cochrane database were thoroughly searched. The odds ratio (OR) with 95% confidence interval (95%CI) was pooled to evaluate the relevance. Meta-regression analysis and subgroup analysis were conducted according to the heterogeneity. A total of 26 studies were identified finally in this meta-analysis. The overall OR was 1.58 (95%CI: 1.36-1.84), which indicated that EGFR mutation had a positive association with BM of NSCLC. The subgroup analysis resulted from eleven studies with lung adenocarcinoma revealed a higher possibility of BM in NSCLC with EGFR mutation compared with EGFR wild (p < 0.05). There was no significant difference in the risk of BM between NSCLC EGFR exon 19 mutation and exon 21 point mutation (p = 0.23). This meta-analysis suggests that EGFR mutation can be a risk factor for BM in NSCLC.