Efficacy of erlotinib for brain and leptomeningeal metastases in patients with lung adenocarcinoma who showed initial good response to gefitinib. J Thorac Oncol. 2009;4:1415-1419. [PMID: 19692934 DOI: 10.1097/jto.0b013e3181b62572]

Novel approaches to treatment of leptomeningeal metastases

PURPOSE OF REVIEW

The incidence of leptomeningeal metastases is increasing in the setting of improved survival from systemic cancers. In more recent years, our understanding of leptomeningeal metastasis pathogenesis, how to diagnose and treat has been evolving.

RECENT FINDINGS

Diagnosing leptomeningeal metastasis has been challenging due to the limitations of cytology and neuroimaging; However, newer techniques detecting circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) have shown potential advantage with diagnosis, quantification and detection of oncogenic mutations. The use of small molecule inhibitors and immunotherapy has shown some promise in specific leptomeningeal metastasis subtypes.

SUMMARY

These new discoveries have improved clinical trials' ability to assess treatment response and thereby more optimally compare different treatments. Furthermore, they have helped the individual clinician better diagnose, monitor the disease and provide novel therapies.

Safety and efficacy of immune checkpoint blockade in patients with advanced nonsmall cell lung cancer and brain metastasis

The presence of brain metastases (BM) is a negative prognostic factor for patients with advanced nonsmall cell lung cancer (NSCLC). Their incidence seems to be higher in patients with oncogene-driven tumours, especially those with EGFR-mutated or ALK-rearranged tumours. Although targeted treatments demonstrate significant efficacy regarding BM, they only apply to a minority of NSCLC patients. On the other hand, systemic therapies for nononcogenic-driven NSCLC with BM have shown limited clinical benefit. In recent years, immunotherapy alone or combined with chemotherapy has been adopted as a new standard of care in first-line therapy. This approach seems to be beneficial to patients with BM in terms of efficacy and toxicity. Combined immune checkpoint inhibition as well as the combination of immunotherapy and radiation therapy show promising results with significant, but overall acceptable toxicity. A pragmatic approach of allowing enrolment of patients with untreated or symptomatic BM in randomised trials evaluating immune checkpoint inhibitors strategies, possibly coupled with central nervous system-related endpoints may be needed to generate data to refine treatment for this patient population.

Niraparib as a therapeutic agent for the treatment of ovarian cancer meningeal dissemination with BRCA1 mutation

This study analyzed a 63-year-old woman with hereditary BRCA1 mutation. She underwent interval debulking surgery after neoadjuvant chemotherapy for high-grade serous ovarian carcinoma (HGSOC). After 2 years of postoperative chemotherapy, she developed headache and dizziness, and a suspected metastatic cerebellar mass in left ovary was detected. Pathological analysis of the mass revealed HGSOC, which was removed surgically. Eight months and another 6 months after the surgery, local recurrence was noted; hence, she underwent CyberKnife treatment. After 3 months, cervical spinal cord metastasis was found, evidenced by left shoulder pain. Moreover, meningeal dissemination was present around the cauda equina. Chemotherapy treatment, including bevacizumab, was ineffective and increased lesions were observed. After CyberKnife treatment for the cervical spinal cord metastasis, niraparib was initiated for the meningeal dissemination. The cerebellar lesions and meningeal dissemination improved within 8 months of niraparib treatment. Although meningeal dissemination is challenging to treat, niraparib may be useful in BRCA-mutated HGSOC.

Clinical Outcomes of Patients with Epidermal Growth Factor Receptor-Mutated Non-Small-Cell Lung Cancer with Leptomeningeal Metastasis in the Modern Target Therapy Era

BACKGROUND

Leptomeningeal metastasis (LM) is a severe complication in patients with non-small-cell lung cancer (NSCLC) and the optimal treatment strategy remains a challenge. This study aimed to investigate the treatment strategies and clinical outcomes in these patients.

METHODS

We retrospectively reviewed the data of 44 patients with epidermal growth factor receptor (EGFR)-mutated NSCLC with LM between 2014 and 2020 at our institute. The patient characteristics, treatment approaches, LM progression-free survival (LMPFS) and overall survival (OS) after the diagnosis of LM (OSLM) were analyzed.

RESULTS

The median OSLM was 16.0 months and the 3-year OS rate was 22.5%. The PFSLM in EGFR T790M-positive NSCLC patients with leptomeingeal disease was significantly improved by initiation of third-generation tyrosine kinase inhibitors (TKIs) compared with that of patients who were T790M negative (14.0 vs. 7.0 months; P = 0.030). A significantly higher LM disease control rate was shown in patients who received third-generation TKIs compared with previous generations of TKIs (90.1% vs. 60.0%; P = 0.024). Better Eastern Cooperative Oncology Group performance status, EGFR exon 19del, and clinical improvement of LM after therapy were independently associated with better OS.

CONCLUSIONS

The survival of patients with NSCLC with LM has improved in the target therapy era. Our study provided real-world clinical evidence that patients with EGFR-mutated NSCLC who developed LM from previous TKIs can be benefit from third-generation EGFR-TKIs, especially for patients with EGFR T790M-positive.

Leveraging Molecular and Immune-Based Therapies in Leptomeningeal Metastases

Leptomeningeal metastases represent an aggressive stage of cancer with few durable treatment options. Improved understanding of cancer biology, neoplastic reliance on oncogenic driver mutations, and complex immune system interactions have resulted in an explosion in cancer-directed therapy in the last two decades to include small molecule inhibitors and immune checkpoint inhibitors. Most of these therapeutics are underexplored in patients with leptomeningeal metastases, limiting extrapolation of extracranial and even intracranial efficacy outcomes to the unique leptomeningeal space. Further confounding our interpretation of drug activity in the leptomeninges is an incomplete understanding of drug penetration through the blood-cerebrospinal fluid barrier of the choroid plexus. Nevertheless, a number of retrospective studies and promising prospective trials provide evidence of leptomeningeal activity of several small molecule and immune checkpoint inhibitors and underscore potential areas of further therapeutic development for patients harboring leptomeningeal disease.

The role of targeted therapy and immune therapy in the management of non-small cell lung cancer brain metastases

Brain metastases are a significant source of morbidity and mortality in patients with non-small cell lung cancer. Historically, surgery and radiation therapy have been essential to maintaining disease control within the central nervous system due to poorly penetrant conventional chemotherapy. With the advent of targeted therapy against actionable driver mutations, there is potential to control limited and asymptomatic intracranial disease and delay local therapy until progression. In this review paper, intracranial response rates and clinical outcomes to biological and immune therapies are summarized from the literature and appraised to assist clinical decision making and identify areas for further research. Future clinical trials ought to prioritize patient-centered quality of life and neurocognitive measures as major outcomes and specifically stratify patients based on mutational marker status, disease burden, and symptom acuity.

Leptomeningeal Metastatic L858R EGFR-mutant Lung Cancer: Prompt Response to Osimertinib in the Absence of T790M-mutation and Effective Subsequent Pulsed Erlotinib

Leptomeningeal carcinomatosis (LMC) is a known sequel of metastatic lung cancer and its treatment is challenging. Nevertheless, treatment options for LMC due to metastatic epidermal growth factor receptor-mutant (EGFR-mutant) lung adenocarcinoma are expanding. We present a 52-year-old male patient with metastatic non-small-cell lung cancer (NSCLC). The patient was found to have L858R mutation in exon 21 of the EGFR gene. He was initially treated with erlotinib, followed by afatinib/cetuximab, followed by chemotherapy. Thereafter, his disease progressed to LMC. Although tissue biopsy did not show T790M-mutation, osimertinib (160 mg once daily) promptly induced clinical and radiological response that continued for five months. High dose pulsed erlotinib (1500 mg weekly) improved his quality of life and extended his survival for a further four months.

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Carcinomatosis under control by osimertinib in EGFR and TP53 mutated lung adenocarcinoma

INTRODUCTION

Approximately 25%-30% of patients with non-small cell lung cancer (NSCLC) develop central nervous system (CNS) metastases during the course of the disease; this percentage is higher in patients with epidermal growth factor receptor (EGFR) mutations. Leptomeningeal metastases, infrequent in the advanced setting, have a particularly dismal prognosis. Osimertinib, a third-generation EGFR inhibitor, can provide effective and durable response in this setting.

CASE DESCRIPTION

We present a 62-year-old man with progressive vomiting, headache, short-term memory impairment, and left lower limb hyposthenia. Computed tomography (CT) showed bilateral lung nodules, multiple lymphadenopathies, liver and bone metastases, and CNS and leptomeningeal dissemination, including multiple parenchymal nodules located at supra- and infratentorial brain. Bone needle biopsy documented TTF1+ lung adenocarcinoma. Whole brain radiotherapy (WBRT) and symptomatic treatments were started. Next-generation sequencing reported deletion of exon 19 of EGFR and mutation 8 of TP53. Osimertinib 80 mg was promptly started and WBRT interrupted. Some days after the patient experienced repetitive seizures and neurologic worsening, antiepileptic drugs and dexamethasone were implemented, with gradual improvement. Radiologic evaluation, including brain MRI and thorax-abdominal CT, showed partial response on CNS as well as extracranial sites, which was sustained.

CONCLUSIONS

First-line treatment with osimertinib can be safe and effective in EGFR-mutated NSCLC even in presence of multiple negative predictive factors (poor Performance Status, diffuse leptomeningeal involvement, TP53 comutation), suggesting that deferring local treatments can be feasible in this setting, allowing the patient to maintain a good quality of life.

[Different Gene Mutation Spectrum of the Paired CSF and Plasma Samples in Lung Adenocarcinoma with Leptomeningeal Metastases: the Liquid Biopsy Based on Circulating Tumor DNA]

背景与目的

软脑膜转移(leptomeningeal metastasis, LM)是晚期非小细胞肺癌(non-small cell lung cancer, NSCLC)的一种严重并发症, 通常预后较差。对于驱动基因阳性的NSCLC患者, 表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptor-tyrosine kinase inhibitors, EGFR-TKIs)是治疗的首选, 但常伴随着无法解决的耐药问题。本研究旨在探讨NSCLC-LM患者的脑脊液(cerebrospinal fluid, CSF)和血液中不同的基因突变谱及突变丰度, 筛查相关耐药基因, 以期能精确指导个体化的治疗。

方法

采用二代基因测序(next generation sequencing, NGS)的液体活检技术, 检测、对比分析TKI耐药后NSCLC患者同期的外周血及脑脊液中的循环肿瘤DNA(circulating tumor DNA, ctDNA)。

结果

共纳入18例NSCLC伴有LM的患者, 基础突变中11例(61.11%)为EGFR, 6例(33.33%)为间变性淋巴瘤激酶(anaplastic lymphoma kinase, ALK), 1例(5.56%)为原癌基因酪氨酸蛋白激酶ROS(ROS proto-oncogene 1, receptor tyrosine kinase, ROS1), 伴随突变中肿瘤蛋白P53(tumor protein p53 gene, TP53)、间质-上皮细胞转化因子(mesenchymal-epithelial transition factor, MET)检出率相对较高。CSF样本的靶向基因突变检出率明显高于外周血(100.00% vs 66.67%, P=0.006), 且基础突变基因的CSF丰度均明显高于血浆样本(P < 0.001)。CSF样本检测出丰富的单核苷酸变异(single-nucleotide variations, SNV)和拷贝数变异(copy number variants, CNV), 数量均多于血液样本；且相较于只接受过单一TKI治疗的患者, 使用多种TKI后脑脊液和血液中会产生更多的SNV突变。

结论

NSCLC-LM患者CSF中的ctDNA, 相较于外周血, 能更加准确、全面地反映出LM的真实基因突变状态, 在指导用药、耐药监测、预后评估等方面具有广泛的应用前景, 可作为液体活检的优选。

High Density of NRF2 Expression in Malignant Cells Is Associated with Increased Risk of CNS Metastasis in Early-Stage NSCLC

Simple Summary

We retrospectively analyzed 304 patients with surgically removed non-small cell lung cancer (NSCLC). Multiplex antibody staining of nuclear factor erythroid 2-related factor 2 (NRF2) and thioredoxin reductase 1 (TrxR1) was conducted and scored in cytokeratin-positive (CK+) cells within the whole-tissue core as well as the tumor and stromal compartments of each tissue microarray (TMA) core. A high density of NRF2+/CK+ cells in the whole-tissue core compartment was an independent prognostic factor, with an eightfold increase in odds regarding the risk of relapse in the central nervous system (CNS). This is the first study to report a tumor-cell-associated protein biomarker for CNS relapse in early-stage lung cancer and the first trial to report the correlation between NRF2 expression and risk of CNS relapse. The results of our study may have an impact on the follow-up strategy for early-stage NSCLC patients and eventually improve their prognosis.

Abstract

Nuclear factor erythroid 2-related factor 2 (NRF2) protein expression promotes cancer progression in non-small cell lung cancer (NSCLC). However, its role in the clinical setting has not been established. We retrospectively analyzed data from 304 patients with surgically removed NSCLC. Multiplex antibody staining of NRF2 and thioredoxin reductase 1 (TrxR1) was conducted and scored in cytokeratin-positive (CK+) cells within the whole-tissue core as well as the tumor and stromal compartments of each tissue microarray (TMA) core. A high density of NRF2+/CK+ cells in the whole-tissue core compartment was correlated with a higher risk of central nervous system (CNS) relapse OR = 7.36 (95% CI: 1.64–33.06). The multivariate analysis showed an OR = 8.00 (95% CI: 1.70–37.60) for CNS relapse in NRF2+/CK+ high-density cases. The density of TrxR1+/CK+ cells failed to show any statistically significant risk of relapse. The OS analyses for NRF2+/CK+ and TrxR1+/CK+ cell density failed to show any statistical significance. This is the first study to report a correlation between NRF2+/CK+ cell density and the risk of CNS relapse in early-stage NSCLC. The results of our study may impact the follow-up strategy for early-stage NSCLC patients and eventually improve their prognosis.

Biological Treatments of Neurofibromatosis Type 2 and Other Skull Base Disorders

Studies of genomic alterations that occur in skull base tumors have provided information regarding biological aberrations that are necessary for the growth and maintenance of these tumors. This has led to the development and initiation of clinical trials incorporating biological treatments for many skull base tumors. The exciting developments of molecularly targeted therapy for the treatment of skull base tumors may provide noninvasive therapeutic options for patients that can be used either alone or in combination with surgery and/or radiation therapy. Future analysis and continued scientific discovery of treatments for skull base tumors can lead to improved outcomes in patients.

[Management of Drug Therapy for Leptomeningeal Metastasis of Sensitive Driver Gene Positive Non-small Cell Lung Cancer]

Leptomeningeal metastasis (LM) is one of the serious complications of advanced non-small cell lung cancer (NSCLC), although the incidence is not high, the clinical symptoms are severe and the prognosis is poor. LM is prone to occur in patients with positive driver gene than negative. At present, the treatment of LM mainly includes molecular targeted therapy, systemic chemotherapy, whole brain radiotherapy, intrathecal chemotherapy and immunotherapy. Although there are many treatments, the efficacy of LM is still unsatisfactory. This article reviews the drug therapy of sensitive driver gene positive NSCLC LM.

Long-term treatment with valganciclovir improves lentiviral suicide gene therapy of glioblastoma

BACKGROUND

Suicide gene therapy for malignant gliomas has shown encouraging results in the latest clinical trials. However, prodrug application was most often restricted to short-term treatment (14 days), especially when replication-defective vectors were used. We previously showed that a substantial fraction of herpes simplex virus thymidine kinase (HSV-TK) transduced tumor cells survive ganciclovir (GCV) treatment in an orthotopic glioblastoma (GBM) xenograft model. Here we analyzed whether these TK+ tumor cells are still sensitive to prodrug treatment and whether prolonged prodrug treatment can enhance treatment efficacy.

METHODS

Glioma cells positive for TK and green fluorescent protein (GFP) were sorted from xenograft tumors recurring after suicide gene therapy, and their sensitivity to GCV was tested in vitro. GBM xenografts were treated with HSV-TK/GCV, HSV-TK/valganciclovir (valGCV), or HSV-TK/valGCV + erlotinib. Tumor growth was analyzed by MRI, and survival as well as morphological and molecular changes were assessed.

RESULTS

TK-GFP+ tumor cells from recurrent xenograft tumors retained sensitivity to GCV in vitro. Importantly, a prolonged period (3 mo) of prodrug administration with valganciclovir (valGCV) resulted in a significant survival advantage compared with short-term (3 wk) application of GCV. Recurrent tumors from the treatment groups were more invasive and less angiogenic compared with primary tumors and showed significant upregulation of epidermal growth factor receptor (EGFR) expression. However, double treatment with the EGFR inhibitor erlotinib did not increase therapeutic efficacy.

CONCLUSION

Long-term treatment with valGCV should be considered as a replacement for short-term treatment with GCV in clinical trials of HSV-TK mediated suicide gene therapy.

Dual Targeting of the Epidermal Growth Factor Receptor Using Combination of Nimotuzumab and Erlotinib in Advanced Non-Small-Cell Lung Cancer with Leptomeningeal Metastases: A Report of Three Cases

Leptomeningeal metastases (LM) occur in 3-5% of patients with advanced non-small-cell lung cancer (NSCLC) and are associated with a dismal prognosis. We report three cases of NSCLC with LM who were treated with the combination of nimotuzumab and erlotinib. Magnetic Resonance Imaging (MRI) evaluation during follow-up showed significant improvement in cancer symptoms and decreased tumor size in all three patients. Grade 3 and 4 toxicities were rarely seen. Based on apparent efficacy of the regimen and fewer side effects, we suggest that nimotuzumab in combination with erlotinib may be a promising option for the treatment of NSCLC with LM.

Brain metastases in oncogene-driven non-small cell lung cancer

Molecular targeted therapies have significantly improved the treatment outcome of patients with non-small cell lung cancer (NSCLC) harboring driver gene mutations such as receptor (EGFR) or anaplastic lymphoma kinase (ALK). However, the brain is a frequent site of recurrence, and it significantly deteriorates the prognosis of these patients. Treatment strategies include surgical resection, whole-brain radiation therapy, stereotactic radiotherapy, and drug therapy depending on patient condition. First-generation EGFR/ALK tyrosine kinase inhibitors (TKI) demonstrates only limited efficacy for intracranial lesions probably because of low penetration through the blood-brain barrier (BBB). However, newly developed TKIs with improved penetration such as osimertinib for EGFR and alectinib, ceritinib, brigatinib, or lorlatinib for ALK have demonstrated significant intracranial activity that should contribute to improved overall survival. Whole-brain radiation therapy used to be a standard of care that confers alleviation of symptom and modest survival benefit. However, it potentially causes neurological and cognitive deficits as a chronic toxicity. With the prolonged survival owing to newer generation drugs, this toxicity is becoming more relevant. Stereotactic radiotherapy is considered when there are three or fewer lesions, and the lesions are <3 cm as local control of tumor is excellent, and neurotoxicity is less. In this review, we discuss the various aspects of brain metastases occurring in NSCLC patients with driver gene mutations. We also propose a treatment algorithm for these patients.

A case of leptomeningeal metastases of human epidermal growth factor receptor 2-positive breast cancer that responded well to lapatinib plus capecitabine

Background:

Leptomeningeal metastases (LM) pose the most difficult form of cancer metastasis to treat and portend a poor prognosis. Standard treatment has yet to be established, and intrathecal chemotherapy and whole- brain radiotherapy are administered on an empirical basis.

Case Description:

We report on a 46-year-old woman with LM from human epidermal growth factor receptor 2 (HER2)-positive breast cancer. She was suffering from intractable headaches, severe nausea and vomiting, and cerebellar ataxia. Contrast-enhanced magnetic resonance imaging (MRI) revealed diffuse enhancement of the meninges, mainly in the posterior cranial fossa, and compression of the cerebellum by the profoundly thickened meninges. The first step in the treatment was decompression of the posterior cranial fossa to relieve intracranial hypertension. After surgery, her symptoms immediately improved. The second step was treatment with lapatinib at 1250 mg and capecitabine 1200 mg, which dramatically improved her symptoms and disappeared diffuse abnormal signal enhancement on MRI.

Conclusion:

We treated a patient with LM from primary HER2-positive breast cancer who responded well to lapatinib plus capecitabine.

Difference in central nerve system metastasis during gefitinib or erlotinib therapy in patients with EGFR-mutated non-small cell lung cancer: a retrospective study

Background

Central nervous system (CNS) metastasis is a poor prognostic factor in patients with advanced non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutation EGFR-mutant NSCLC and is associated with a deteriorated quality of life (QOL). Some clinical studies have suggested a possible difference in the incidence of CNS metastasis between EGFR-mutant NSCLC patients treated with gefitinib and erlotinib, both of which are classified as first-generation EGFR tyrosine kinase inhibitors (TKIs). However, the difference in the incidence of CNS metastasis between patients receiving these two drugs has not yet been sufficiently well investigated. We analyzed the frequency of occurrence/progression of CNS metastasis in EGFR-mutant NSCLC patients treated with erlotinib and gefitinib as the first-line treatment.

Methods

We analyzed the incidence of CNS metastasis, frequency of progression of CNS metastasis and the treatment outcomes in EGFR-mutant patients who received gefitinib or erlotinib as the first-line EGFR-TKI treatment. CNS progressive disease (PD) was defined as progression of CNS metastasis during EGFR-TKI treatment. We also evaluated the progression-free survival (PFS), CNS-PFS, and overall survival (OS) of the patients who received each of the two drugs.

Results

A total of 170 patients were enrolled in the study, of which 144 had received gefitinib, and 26 had received erlotinib. The frequency of CNS PD in the erlotinib group tended to be lower than that in the gefitinib group (11.5% vs. 29.9%, P=0.06). In patients with no existing CNS metastasis at the start of the EGFR-TKI treatments, the incidence of CNS PD was significantly lower in the erlotinib group than that in the gefitinib group (4.8% vs. 24.5%, P=0.04). A re-biopsy after failure of EGFR-TKI treatment was performed in 48 patients. The incidence of EGFR T790M tended to be higher among patients with CNS PD than in those without CNS PD, although the difference was not statistically significant (66.7% vs. 40.4%; P=0.23).

Conclusions

The incidence of progression of CNS metastasis during erlotinib treatment was lower than that during gefitinib treatment. In addition, the difference in the incidence in patients without existing CNS metastasis at the time of start of EGFR-TKI treatment was significantly lower in the patients treated with erlotinib than in those treated with gefitinib.

Clinical outcomes and secondary epidermal growth factor receptor (EGFR) T790M mutation among first-line gefitinib, erlotinib and afatinib-treated non-small cell lung cancer patients with activating EGFR mutations

Gefitinib, erlotinib and afatinib are approved for first-line treatment of advanced non-small cell lung cancer (NSCLC) bearing an activating epidermal growth factor receptor (EGFR) mutation. However, the clinical outcomes among the three EGFR tyrosine kinase inhibitors (TKIs) are still controversial. We aimed to evaluate clinical outcomes and secondary EGFR T790M mutation among the three EGFR TKIs. From May 2014 to January 2016, a total of 301 patients received treatment with gefitinib, erlotinib or afatinib, for first-line treatment of advanced NSCLC with an activating EGFR mutation, based on their clinicians' choice. The median overall survival (OS) was 37.0 months. Although the baseline characteristics of patients were unequal, progression-free survival and OS did not differ among the 3 groups. Multivariate analysis found that gefitinib (adjusted odds ratio [aOR] 3.29, 95% confidence interval [CI], 1.15-9.46, p = 0.027), EGFR TKI treatment duration more than 13 months (aOR 3.16, 95% CI, 1.20-8.33, p = 0.020), male (aOR 3.25, 95% CI, 1.10-9.66, p = 0.034), initial liver metastasis (aOR 4.97, 95% CI 1.18-20.96, p = 0.029) and uncommon EGFR mutation (aOR 0.14, 95% CI, 0.02-0.97, compared to EGFR deletion 19, p = 0.047) were independent factors for secondary T790M mutation. In real-world practice, choosing first line EGFR TKI based on the patients' clinical characteristics yielded good clinical outcomes. First-line gefitinib, longer EGFR TKI treatment duration, male, initial liver metastasis and uncommon EGFR mutations may be independent factors for secondary EGFR T790M mutation.

Erlotinib versus gefitinib for brain metastases in Asian patients with exon 19 EGFR-mutant lung adenocarcinoma: a retrospective, multicenter study

Background

The purpose of this study was to compare clinical outcomes of Erlotinib versus Gefitinib in the treatment of Asian patients with exon 19 EGFR-mutant lung adenocarcinoma and newly diagnosed brain metastases.

Methods

Consecutive Asian patients with exon 19 EGFR-mutant lung adenocarcinoma and newly diagnosed brain metastases were identified and initially received peroral administration of 150 mg/d erlotinib or 250 mg/d gefitinib during 2009–2015. Overall survival (OS) was the primary endpoint. Progression-free survival (PFS) was the second endpoint.

Results

The cohort consisted of 227 Asian patients (erlotinib-treated cohort: n = 112, mean age = 58.5 years [SD: 20.13]; gefitinib-treated cohort: n = 115, mean age = 58.4 years [SD: 19.52]). In a multivariate analysis controlling for age, sex and time span of smoking history, significant difference was detected in the 36-month OS between erlotinib and gefitinib groups (58.3% vs. 49.1%, p = 0.012). There was also significant difference in the 36-month PFS between erlotinib and gefitinib groups (64% vs. 53%, p = 0.013).

Conclusion

For Asian patients with exon 19 EGFR-mutant lung adenocarcinoma and brain metastases, erlotinib was associated with a significantly longer OS and a more prolonged PFS and compared with gefitinib.

Penetrating the evidence of EGFR and ALK tyrosine kinase inhibitors for non-small cell lung cancer brain metastases

The brain is a common metastatic site in lung cancer. Approximately one-third of patients will develop brain metastases during the course of their disease. Median overall survival has been reported between 3 and 14.8 months in patients with brain metastases compared to other metastatic sites. In addition, the lifetime incidence of brain metastases is increasing due to prolonged survival seen in non-small cell lung cancer (NSCLC) patients due to new systemic therapies and improved neuro-imaging techniques. Several targeted therapies-such as tyrosine kinase inhibitors targeting epidermal growth factor receptors and anaplastic lymphoma kinase-are active in NSCLC and have data to suggested possible effectiveness against brain metastases in these patients.

Leptomeningeal metastasis

Leptomeningeal metastasis (LM) results from dissemination of cancer cells to both the leptomeninges (pia and arachnoid) and cerebrospinal fluid (CSF) compartment. Breast cancer, lung cancer, and melanoma are the most common solid tumors that cause LM. Recent approval of more active anticancer therapies has resulted in improvement in survival that is partly responsible for an increased incidence of LM. Neurologic deficits, once manifest, are mostly irreversible, and often have a significant impact on patient quality of life. LM-directed therapy is based on symptom palliation, circumscribed use of neurosurgery, limited field radiotherapy, intra-CSF and systemic therapies. Novel methods of detecting LM include detection of CSF circulating tumor cells and tumor cell-free DNA. A recent international guideline for a standardization of response assessment in LM may improve cross-trial comparisons as well as within-trial evaluation of treatment. An increasing number of retrospective studies suggest that molecular-targeted therapy, such as EGFR and ALK inhibitors in lung cancer, trastuzumab in HER2+ breast cancer, and BRAF inhibitors in melanoma, may be effective as part of the multidisciplinary management of LM. Prospective randomized trials with standardized response assessment are needed to further validate these preliminary findings.

Management of Brain Metastases in Epidermal Growth Factor Receptor Mutant Non-Small-Cell Lung Cancer

Lung cancer remains a leading cause of mortality with 1.69 million deaths worldwide. Activating mutations in epidermal growth factor receptor (EGFR), predominantly exon 19 deletions and exon 21 L858R mutations, are known oncogenic drivers identified in 20-40% of non-small-cell lung cancers (NSCLC). 70% of EGFR-mutant NSCLC patients develop brain metastases (BM), compared to 38% in EGFR wild-type patients. First-generation tyrosine kinase inhibitors (TKIs), such as erlotinib and gefitinib have proven to be superior to chemotherapy in the front-line treatment of EGFR-mutant NSCLC, as has afatinib, a second-generation TKI. The most common acquired resistance mechanism is the development of a gatekeeper mutation in exon 20 T790M. Osimertinib has emerged as a third-generation EGFR TKI with proven activity in the front-line setting as well as in patients with a T790M acquired resistance mutation with remarkable CNS activity. As long-term survival outcomes in EGFR-mutant NSCLC continue to improve, the burden of BM becomes a greater challenge. Here, we review the literature related to the management of BM in EGFR-mutant NSCLC including the role of the three generations of EGFR TKIs, immunotherapy, and brain radiation.

Medical Treatment Options for Patients with Epidermal Growth Factor Receptor Mutation-Positive Non-Small Cell Lung Cancer Suffering from Brain Metastases and/or Leptomeningeal Disease

Brain metastases and/or leptomeningeal disease (LMD) with associated central nervous system (CNS) metastases are known complications of advanced epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC). It is important, therefore, to assess the activity of EGFR tyrosine kinase inhibitors (TKIs) versus such CNS complications. This review explores the literature reporting the intracranial activity of EGFR TKIs, and finds that there is evidence for varying efficacy of the approved agents, erlotinib, gefitinib, afatinib, and osimertinib in patients with CNS metastases. Other EGFR TKIs in development, such as AZD3759, may have a future role as therapeutic options in this setting. Emerging evidence indicates that the second- and third-generation EGFR TKIs, afatinib and osimertinib, effectively penetrate the blood-brain barrier, and therefore represent viable treatment options for CNS lesions, and can reduce the risk of CNS progression. These agents should therefore be considered as first-line treatment options in patients with EGFR mutation-positive NSCLC who have brain metastases and/or LMD. While there are currently no prospective data comparing the intracranial efficacy of second- and third-generation EGFR TKIs in this setting, CNS activity and protection offered by different EGFR TKIs should be an additional consideration when making decisions about the optimal sequence of treatment with EGFR TKIs in order to maximize survival benefit in individual patients.

Role of Epidermal Growth Factor Receptor (EGFR) Inhibitors and Radiation in the Management of Brain Metastases from EGFR Mutant Lung Cancers

The growth of genotype-directed targeted therapies, such as inhibitors of the epidermal growth factor receptor (EGFR), has revolutionized treatment for some patients with oncogene-addicted lung cancer. However, as systemic control for these patients has improved, brain metastases remain an important source of morbidity and mortality. Traditional treatment for brain metastases has been radiotherapy, either whole-brain radiation or stereotactic radiosurgery. The growing availability of drugs that can cross the blood-brain barrier and have activity in the central nervous system (CNS) has led to many studies investigating whether targeted therapy can be used in combination with or in lieu of radiation. In this review, we summarize the key literature about the incidence and nature of EGFR-mutant brain metastases (EGFR BMs), the data about the activity of EGFR inhibitors in the CNS, and whether they can be used as front-line therapy for brain metastases. Although initial use of tyrosine kinase inhibitors for EGFR BMs can often be an effective treatment strategy, multidisciplinary evaluation is critical, and prospective studies are needed to clarify which patients may benefit from early radiotherapy.

IMPLICATIONS FOR PRACTICE

Management of brain metastases in epidermal growth factor receptor (EGFR) mutant lung cancer is a common clinical problem. The question of whether to start initial therapy with an EGFR inhibitor or radiotherapy (either whole-brain radiotherapy or stereotactic radiosurgery) is controversial. The development of novel EGFR inhibitors with enhanced central nervous system (CNS) penetration is an important advance in the treatment of CNS disease. Multidisciplinary evaluation and evaluation of extracranial disease status are critical to choosing the best treatment option for each patient.

Tyrosine kinase inhibitors show different anti-brain metastases efficacy in NSCLC: A direct comparative analysis of icotinib, gefitinib, and erlotinib in a nude mouse model

Brain metastasis is an increasing problem in non-small cell lung cancer (NSCLC) patients. Tyrosine kinase inhibitors (TKIs), including gefitinib, erlotinib, and icotinib, are reported to be effective in patients with brain metastases. However, direct comparative studies of the pharmacokinetics and efficacy of these three drugs in treating brain metastases are lacking. In the present investigation, we found that gefitinib penetrated the blood-tumor barrier and was distributed to brain metastases more effectively than erlotinib or icotinib in a nude mouse model. The 1-h ratio of brain metastases to plasma concentration for gefitinib, erlotinib, and icotinib was 9.82±1.03%, 4.83±0.25%, and 2.62±0.21%, respectively. The 2-h ratio of brain metastases to plasma concentration for gefitinib, erlotinib, and icotinib was 15.11±2.00%, 5.73±1.31%, and 2.69±0.31%, respectively. Gefitinib exhibited the strongest antitumor activity (p_{gefitinib vs. erlotinib}=0.005; p_{gefitinib vs. icotinib}=0.002). Notably, erlotinib exhibited a better treatment efficacy than icotinib (p=0.037). Consistently, immunohistochemical data showed that TKIs differentially inhibit the proliferation of metastatical tumor cells. Gefitinib and erlotinib markedly inhibited the proliferation of tumor cells, while there were more ki-67-positive tumor cells in the icotinib group. Additionally, gefitinib inhibited the phosphorylation of EGFR better than the other drugs, whereas pEGFR expression levels in erlotinib groups were lower than levels in the icotinib group (p_{gefitinib vs. erlotinib}=0.995; p_{gefitinib vs. icotinib}=0.028; p_{erlotinib vs. icotinib}=0.042).Altogether, our findings suggest that gefitinib and erlotinib can inhibit the growth of PC-9-luc brain tumors. Gefitinib demonstrated better antitumor activity and penetration rate in brain metastases than erlotinib or icotinib.

Continuing EGFR-TKI beyond radiological progression in patients with advanced or recurrent, EGFR mutation-positive non-small-cell lung cancer: an observational study

BACKGROUND

Some patients with advanced or recurrent, epidermal growth factor receptor (EGFR) mutation-positive (EGFR M+) non-small-cell lung cancer (NSCLC) continue to receive EGFR tyrosine kinase inhibitors (TKIs) beyond radiological progression.

METHODS

We analysed a cohort of 577 patients with EGFR M+ NSCLC, who had received a first-line EGFR-TKI. We classified patients according to clinical course and treatment patterns at Response Evaluation Criteria in Solid Tumors (RECIST) progressive disease (PD). We evaluated the period from RECIST PD to TKI discontinuation or clinical PD and also evaluated survival after RECIST PD and compared it between groups.

RESULTS

RECIST PD was documented in 451 cases, of which 283 (62.7%) were clinically stable. 186 (65.7%) discontinued and 97 (34.3%) continued the EGFR-TKI. In those who continued EGFR-TKI, median time between RECIST PD and clinical PD or TKI discontinuation was 5.1 months. Median survival after RECIST PD in patients who discontinued and continued EGFR-TKI after clinically stable RECIST PD was 14.6 and 15.3 months (p=0.5489), respectively. In multivariate analysis, continuing EGFR-TKI therapy, female gender, better performance status and exon 19 deletion subtype were likely positive predictive factors for survival after clinically stable RECIST PD.

CONCLUSION

Our study suggests that some patients could benefit from receiving an EGFR-TKI beyond radiological progression.

A Neuro-oncologist's Perspective on Management of Brain Metastases in Patients with EGFR Mutant Non-small Cell Lung Cancer

Management of non-small cell lung cancer (NSCLC) with brain metastasis (BrM) has been revolutionized by identification of molecular subsets that have targetable oncogenes. Historically, survival for NSCLC with symptomatic BrM was weeks to months. Now, many patients are surviving years with limited data to guide treatment decisions. Tumors with activating mutations in epidermal growth factor receptor (EGFRact+) have a higher incidence of BrM, but a longer overall survival. The high response rate of both systemic and BrM EGFRact+ NSCLC to tyrosine kinase inhibitors (TKIs) has led to the rapid incorporation of new therapies but is outpacing evidence-based decisions for BrM in NSCLC. While whole brain radiation therapy (WBRT) was the foundation of management of BrM, extended survival raises concerns for the subacute and late effects radiotherapy. We favor the use of TKIs and delaying the use of WBRT when able. At inevitable disease progression, we consider alternative dosing schedules to increase CNS penetration (such as pulse dosing of erlotinib) or advance to next generation TKI if available. We utilize local control options of surgery or stereotactic radiosurgery (SRS) for symptomatic accessible lesions based on size and edema. At progression despite available TKIs, we use pemetrexed-based platinum doublet chemotherapy or immunotherapy if the tumor has high expression of PDL-1. We reserve the use of WBRT for patients with more than 10 BrM and progression despite TKI and conventional chemotherapy, if performance status is appropriate.

Retrospective analysis of survival in patients with leptomeningeal carcinomatosis from lung adenocarcinoma treated with erlotinib and gefitinib

Background

Leptomeningeal carcinomatosis is a relatively rare metastatic form of non-small cell lung cancer, which can impact prognosis. There is an increasing need for selecting suitable epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors among those currently included in standard care for EGFR mutation-positive patients. We compared the efficacy of gefitinib and erlotinib in survival of patients with leptomeningeal carcinomatosis.

Patients and methods

The medical records of 269 patients who received tyrosine kinase inhibitors at a single center were retrospectively reviewed. Overall, 22 patients (8.2%) were treated with tyrosine kinase inhibitors for leptomeningeal carcinomatosis from non-small cell lung cancer with EGFR mutation between 2006 and 2016. Time to death from leptomeningeal carcinomatosis diagnosis was compared between the gefitinib and erlotinib groups.

Results

Gefitinib and erlotinib were administrated to 5 and 17 patients, respectively. Median progression-free survival was longer in the erlotinib group than in the gefitinib group (6.60 vs 2.12 months, P = 0.07). Overall survival was more than twice as long in the erlotinib arm compared with that in the gefitinib arm (7.20 vs 2.99 months, P = 0.32). Response in patients with exon 19 deletion was better than in those with exon 21 mutation (overall survival, 7.20 and 5.62 months, respectively, P = 0.12).

Conclusions

Erlotinib seemed more effective than gefitinib in prolonging survival in leptomeningeal carcinomatosis from EGFR mutation-positive non-small cell lung cancer and may be particularly beneficial in patients with EGFR exon 19 mutations, warranting further studies.

Nasogastric tube-administered alectinib achieved long-term survival in a crizotinib-refractory nonsmall cell lung cancer patient with a poor performance status

Alectinib shows remarkable efficacy against anaplastic lymphoma kinase (ALK)-positive nonsmall cell lung cancer (NSCLC), with minimal adverse effects. Therefore, alectinib may provide a survival benefit to ALK-positive NSCLC patients with a poor performance status. If the medication cannot be taken by mouth, the patient may be given alectinib through a nasogastric tube.

Successful osimertinib treatment for leptomeningeal carcinomatosis from lung adenocarcinoma with the T790M mutation of EGFR

Osimertinib is a third-generation tyrosine kinase inhibitor (TKI) of the epidermal growth factor receptor (EGFR) that has been approved for the treatment of metastatic non-small cell lung cancer (NSCLC) positive for the secondary T790M mutation of EGFR. In a preclinical study, it also showed efficacy against leptomeningeal carcinomatosis (LMC) derived from NSCLC resistant to first-generation and second-generation EGFR-TKIs. We now report the case of a patient aged 70 years with symptomatic LMC derived from NSCLC with the T790M mutation of EGFR who showed a clinical and radiographic response to osimertinib.

Pulsatile Erlotinib in EGFR-Positive Non-Small-Cell Lung Cancer Patients With Leptomeningeal and Brain Metastases: Review of the Literature

Patients with epidermal growth factor receptor (EGFR)-positive (EGFR⁺) non-small-cell lung cancer (NSCLC) show improved response rates when treated with tyrosine kinase inhibitors (TKIs) such as erlotinib. However, standard daily dosing of erlotinib often does not reach therapeutic concentrations within the cerebrospinal fluid (CSF), resulting in progression of central nervous system (CNS) disease. Intermittent, high-dose administration of erlotinib reaches therapeutic concentrations within the CSF and is well tolerated in patients. Experience with "pulsatile" dosing, however, is limited. We review the literature on the pharmacology and clinical outcomes of pulsatile erlotinib in the treatment of EGFR⁺ NSCLC with brain and leptomeningeal metastases, and include available data on the use of next-generation TKIs in CNS progression. We also provide our institution's experience with patients treated with pulsatile erlotinib for CNS metastasis, and propose clinical criteria for its use. Pulsatile erlotinib is a reasonable alternative in EGFR⁺ patients with new or worsening CNS disease, without evidence of systemic progression, and without confirmed T790M resistance mutations within the CNS.

Downregulation of EGFR in a metastatic brain lesion of EGFR-mutated non-small cell lung cancer using a tyrosine kinase inhibitor: A case report

Brain metastasis is a common complication in patients with cancer, with lung cancer being the most frequent origin of brain metastases. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have begun to serve a pivotal role in lung cancer treatment and have been reported to demonstrate anticancer activity against brain metastases by penetrating the blood-brain barrier. The present study reports, to the best of our knowledge, the first case of EGFR-mutated non-small cell lung cancer (NSCLC) brain metastasis that was surgically resected while the lesion was responding to the EGFR-TKI erlotinib. The results of the present study demonstrated that EGFR-mutated NSCLC cells were able to evade the cytotoxic effect of EGFR-TKI by downregulating EGFR expression, without exhibiting the T790M EGFR mutation.

Rapid intracranial response to osimertinib, without radiotherapy, in nonsmall cell lung cancer patients harboring the EGFR T790M mutation: Two Case Reports

RATIONALE

Most of nonsmall cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) activating mutations eventually acquire resistance to the first EGFR-tyrosine kinase inhibitors (TKIs) therapy after varying periods of treatment. Of note, approximately one-third of those patients develop brain metastases, which deteriorate their quality of life and survival. The effect of systemic chemotherapy on brain metastases after acquisition of EGFR-TKI resistance is limited, and thus far, whole-brain radiation therapy, which may cause the harmful effect on neurocognitive functions, has been the only established therapeutic option for especially symptomatic brain metastases. Osimertinib is a third-generation oral, potent, and irreversible EGFR-TKI. It can bind to EGFRs with high affinity even when the EGFR T790M mutation exists in addition to the sensitizing mutations. Its clinical efficacy for NSCLC patients harboring the T790M mutation has already been shown; however, the evidence of osimertinib on brain metastases has not been documented well, especially in terms of the appropriate timing for treatment and its response evaluation.

PATIENT CONCERNS, DIAGNOSES, AND INTERVENTIONS

We experienced 2 NSCLC patients with the EGFR T790M mutation; a 67-year-old woman with symptomatic multiple brain metastases administered osimertinib as seventh-line chemotherapy, and a 76-year old man with an asymptomatic single brain metastasis administered osimertinib as fifth-line chemotherapy.

OUTCOMES

These patients showed great response to osimertinib within 2 weeks without radiation therapy.

LESSONS

These are the first reports to reveal the rapid response of the brain metastases to osimertinib within 2 weeks. These cases suggest the possibility that preemptive administration of osimertinib may help patients to postpone or avoid radiation exposures. In addition, rapid reassessment of the effect of osimertinib on brain metastases could prevent patients from being too late to receive essential radiotherapy.

Leptomeningeal Disease and the Evolving Role of Molecular Targeted Therapy and Immunotherapy

BACKGROUND

Leptomeningeal disease (LMD) is a complication that results from solid tumor metastasis. Prognosis is extremely poor. As therapeutic options for solid tumors improve, the rate of LMD continues to increase. Until recently, treatment has been limited to radiation therapy, intrathecal chemotherapy, and systemic chemotherapy, with an overall survival of 2-3 months. Targeted molecular therapy and immunotherapies are promising new options for increasing overall survival and clinical improvement; however, optimal clinical management remains unknown.

METHODS

In this review, we discuss targeted molecular therapy and immunotherapy treatment options for LMD resulting from primary lung, breast, and melanoma tumors. In addition, we summarize dosing strategies, overall survival, clinical outcomes, and novel approaches to treatment.

RESULTS

Our review indicates a deficiency in the current literature. Presently, intrathecal trastuzumab administration may be an effective option for patients with HER2-positive breast cancer. BRAF inhibitors and cytotoxic T lymphocyte-associated antigen-4 targets have shown promising results in LMD resulting from melanoma. Finally, tyrosine kinase inhibitors may increase overall survival in epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer. Pulsatile drug administration or dual therapy may be beneficial for patients who progress to LMD while being treated with EGFR targets for their primary malignancy.

CONCLUSION

Targeted molecular therapy and immunotherapy in LMD may provide favorable treatment options. Current literature is lacking in safety, efficacy, and overall response rates from the use of targeted therapy. Research is needed to draw significant conclusions about the most appropriate therapy for patients with LMD.

Systemic therapy of brain metastases: non-small cell lung cancer, breast cancer, and melanoma

Brain metastases (BM) occur frequently in many cancers, particularly non-small cell lung cancer (NSCLC), breast cancer, and melanoma. The development of BM is associated with poor prognosis and has an adverse impact on survival and quality of life. Commonly used therapies for BM such as surgery or radiotherapy are associated with only modest benefits. However, recent advances in systemic therapy of many cancers have generated considerable interest in exploration of those therapies for treatment of intracranial metastases.This review discusses the epidemiology of BM from the aforementioned primary tumors and the challenges of using systemic therapies for metastatic disease located within the central nervous system. Cumulative data from several retrospective and small prospective studies suggest that molecularly targeted systemic therapies may be an effective option for the treatment of BM from NSCLC, breast cancer, and melanoma, either as monotherapy or in conjunction with other therapies. Larger prospective studies are warranted to further characterize the efficacy and safety profiles of these targeted agents for the treatment of BM.

Clinical Efficacy of Afatinib Treatment for a Patient with Leptomeningeal Carcinomatosis

Leptomeningeal metastases occur in 1% of patients with non-small-cell lung cancer. There have been several reports on the treatment of leptomeningeal metastases with afatinib. Our patient was a 41-year-old woman who had never smoked and was diagnosed with stage IV adenocarcinoma of the lung with an epidermal growth factor receptor (EGFR) mutation. She was treated with afatinib for the recurrence of leptomeningeal metastases. After the treatment with afatinib was initiated, the neurological symptoms dramatically regressed, and she achieved progression-free survival for 7 months. The concentration of afatinib in the cerebrospinal fluid (CSF) ranged from 0.05 to 0.14 ng/mL, and the penetration rate of afatinib from the plasma to the CSF ranged from 0.28 to 0.40%. This concentration might be sufficient to achieve a clinical effect for leptomeningeal carcinomatosis. Therefore, afatinib administered at the usual doses may be an effective treatment for leptomeningeal carcinomatosis of EGFR-mutated or EGFR-tyrosine kinase inhibitor-sensitive lung adenocarcinoma.

Epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of central nervous system metastases from non-small cell lung cancer: the present and the future

Lung cancer is one of the major causes of cancer related mortality worldwide. Brain metastases (BM) complicate clinical evolution of non-small cell lung cancer (NSCLC) in approximately 25-40% of cases, adversely influencing quality of life (QoL) and overall survival (OS). Systemic therapy remains the standard strategy for metastatic disease. Nevertheless, the blood-brain barrier (BBB) makes central nervous system (CNS) a sanctuary site. To date, the combination of chemotherapy with whole brain radiation therapy (WBRT), surgery and/or stereotactic radiosurgery (SRS) represents the most used treatment for patients (pts) with intracranial involvement. However, due to their clinical conditions, many pts are not able to undergo local treatments. Targeted therapies directed against epidermal growth factor receptor (EGFR), such as gefitinib, erlotinib and afatinib, achieved important improvements in EGFR mutated NSCLC with favorable toxicity profile. Although their role is not well defined, the reported objective response rate (ORR) and the good tolerance make EGFR-tyrosine kinase inhibitors (TKIs) an interesting valid alternative for NSCLC pts with BM, especially for those harboring EGFR mutations. Furthermore, new-generation TKIs, such as osimertinib and rociletinib, have already shown important activity on intracranial disease and several trials are still ongoing to evaluate their efficacy. In this review we want to highlight literature data about the use and the effectiveness of EGFR-TKIs in pts with BM from NSCLC.

Continuing EGFR inhibition beyond progression in advanced non-small cell lung cancer

The majority of patients with epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) respond to first-line EGFR tyrosine kinase inhibitors (TKIs), but nearly all inevitably acquire resistance and develop disease progression. Conventional practice would be to switch treatments to second-line therapy. However, continuing TKIs beyond progression is becoming increasingly commonplace in patients with indolent, small volume asymptomatic growth, who may potentially continue to derive ongoing clinical benefit and to avoid a 'withdrawal tumour flare'. Nevertheless, there are limitations to our current criteria for assessing disease response, which are based on radiological assessments without considering symptomatic benefit, or the complex molecular and clinical heterogeneity of tumour growth and drug response patterns. In this article, we review the rationale for continuing EGFR inhibitors in patients with EGFR mutant NSCLC beyond disease progression and discuss strategies that have been pursued in the context of molecularly and clinically heterogeneous populations of tumour growth depending on the different clinical scenarios encountered. We discuss the management of systemic disease progression, including continuing EGFR TKIs alone, introducing a drug holiday, or combining TKIs with chemotherapy or other molecularly targeted agents. We also focus on approaches in managing patients with indolent, small volume asymptomatic growth (non-CNS oligometastatic disease progression) and those with oligometastatic EGFR mutant NSCLC with involvement of the central nervous system. We envision future precision medicine strategies through the use of next generation sequencing strategies of serial tumour rebiopsies and circulating plasma DNA to individualise the management for such patients during disease progression.

EGFR mutation status of paired cerebrospinal fluid and plasma samples in EGFR mutant non-small cell lung cancer with leptomeningeal metastases

PURPOSE

Central nervous system (CNS) is the prevalent site for metastases in epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-relapsed NSCLC patients. To understand the EGFR mutation status in paired cerebrospinal fluid (CSF) and plasma samples after EGFR-TKI treatment failure might be useful to guide the treatment of intra- and extracranial tumors in those patients.

METHODS

Paired CSF and plasma samples were collected from seven NSCLC patients with CNS metastases after EGFR-TKI failure. EGFR mutations were tested by amplification refractory mutation system (ARMS) and droplet digital PCR (ddPCR) methods. Gefitinib concentrations were evaluated by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS).

RESULTS

EGFR mutations were detected in all seven CSF samples, including three of E19-Del, three of L858R and one of E19-Del&T790M by both methods. On the other hand, majority of the matched plasma samples (5/7) were negative for EGFR mutations by both methods. The other two plasma samples were positive for E19-Del&T790M by ddPCR, and one of them had undetectable T790M by ARMS. Gefitinib concentration in CSF was much lower than that in plasma (mean CSF/plasma ratio: 1.8 %).

CONCLUSIONS

After EGFR-TKI failure, majority of the NSCLC patients with CNS metastases remained positive detection of EGFR sensitive mutations in CSF, but much less detection in the matched plasma. Significantly low exposure of gefitinib in CSF might explain the intracranial protection of the EGFR sensitive mutation positive tumor cells.

Survival of patients with brain metastases from non-small cell lung cancer harboring EGFR mutations treated with epidermal growth factor receptor tyrosine kinase inhibitors

Brain metastases (BM) is one of the most crucial distant metastases in patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. There is no consensus about which EGFR tyrosine kinase inhibitor (TKI) is most effective against BM in such patients. Here, we compared prognoses of patients with EGFR-TKI naïve EGFR-positive BM treated with erlotinib or gefitinib after BM diagnosis. Of 269 patients with NSCLC treated with EGFR-TKIs at a single institution, we reviewed medical records of 205 patients with documented EGFR mutations. Eleven patients were administered erlotinib, and 52 patients were administered gefitinib as the first-line EGFR-TKI treatment after diagnosis. We used propensity score matching to balance patient backgrounds between groups, and the log-rank test to compare survival curves. Patients with BM at the induction of chemotherapy had a poorer prognosis than those without BM [median overall survival (OS) 18.5 vs. 28.0 months]. Meanwhile, there was no significant difference in OS between those with or without BM at the initiation of EGFR-TKI treatment (20.3 vs. 23.8 months). Median OS of patients treated with erlotinib was not significantly longer than that of patients treated with gefitinib (25.0 vs. 18.1 months). The presence of BM at the initiation of EGFR-TKI treatment had no apparent effect on survival. Erlotinib was deemed more effective than gefitinib in preventing intracranial lesions and prolonging survival; however, prospective studies are needed to confirm these results.

The role of EGFR-TKI for leptomeningeal metastases from non-small cell lung cancer

Leptomeningeal metastasis (LM) is a terminal event in the development of non-small cell lung cancer (NSCLC). It has a poor prognosis with median survival of 1.9 months if untreated. The improvement of OS in NSCLC patients relatively increases incidence of LM. While current therapeutic options for LM are limited. Epidermal growth factor receptor-tyrosine kinase inhibitors are a class of small molecules and show dramatic response in epidermal growth factor receptor mutated patients. It also has a distinct therapeutic potential against brain metastases. Although there are some studies on EGFR-TKIs and brain metastases, the role of EGFR-TKIs on LM are not fully clarified. In this review, we will summarize current evidences concerning the use and discuss the role of EGFR-TKIs on LM.

Evaluating Cancer of the Central Nervous System Through Next-Generation Sequencing of Cerebrospinal Fluid

PURPOSE

Cancer spread to the central nervous system (CNS) often is diagnosed late and is unresponsive to therapy. Mechanisms of tumor dissemination and evolution within the CNS are largely unknown because of limited access to tumor tissue.

MATERIALS AND METHODS

We sequenced 341 cancer-associated genes in cell-free DNA from cerebrospinal fluid (CSF) obtained through routine lumbar puncture in 53 patients with suspected or known CNS involvement by cancer.

RESULTS

We detected high-confidence somatic alterations in 63% (20 of 32) of patients with CNS metastases of solid tumors, 50% (six of 12) of patients with primary brain tumors, and 0% (zero of nine) of patients without CNS involvement by cancer. Several patients with tumor progression in the CNS during therapy with inhibitors of oncogenic kinases harbored mutations in the kinase target or kinase bypass pathways. In patients with glioma, the most common malignant primary brain tumor in adults, examination of cell-free DNA uncovered patterns of tumor evolution, including temozolomide-associated mutations.

CONCLUSION

The study shows that CSF harbors clinically relevant genomic alterations in patients with CNS cancers and should be considered for liquid biopsies to monitor tumor evolution in the CNS.

Management of NSCLC Disease Progression After First-Line EGFR Tyrosine Kinase Inhibitors: What Are the Issues and Potential Therapies?

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) represent the standard of care for advanced non-small cell lung cancer (NSCLC) patients whose tumor harbors an activating EGFR mutation. The vast majority of patients will experience disease control with an EGFR-TKI but inevitably all patients will progress, often within a year of treatment. There is no current standard of care for this scenario but, in clinical practice, most of the patients will be offered platinum-based doublet chemotherapy. In some situations, continuation of the EGFR-TKI beyond radiological progression, with or without use of local treatments in case of oligo-progressive disease, represents a reasonable therapeutic option. The aim of this review is to describe the different treatment strategies that have been developed to tackle progression on EGFR-TKIs, including specific clinical scenarios and novel agents designed to tackle the common T790M resistance mutation.

Targeted therapy combined with radiotherapy in non-small-cell lung cancer: a review of the Oncologic Group for the Study of Lung Cancer (Spanish Radiation Oncology Society)

In recent years, major advances in our understanding of the molecular biology of lung cancer, together with significant improvements in radiotherapy technologies, have revolutionized the treatment of non-small cell lung cancer (NSCLC). This has led to the development of new therapies that target molecular mutations specific to each tumor type, acting on the cell surface antigens or intracellular signaling pathways, or directly affecting cell survival. At the same time, ablative dose radiotherapy can be delivered safely in the context of metastatic disease. In this article, the GOECP/SEOR (Oncological Group for Study of Lung Cancer/Spanish Society of Radiation Oncology) reviews the role of new targeted therapies used in combination with radiotherapy in patients with locally advanced (stage III) NSCLC and in patients with advanced, metastatic (stage IV) NSCLC.

Comparison of erlotinib and pemetrexed as second-/third-line treatment for lung adenocarcinoma patients with asymptomatic brain metastases

Objective

Brain metastases occur in one-third of all non-small-cell lung cancer patients. Due to restrictive transport at the blood–brain barrier, many drugs provide poor control of metastases in the brain. The aim of this study was to compare erlotinib with pemetrexed as second-/third-line treatment in patients with lung adenocarcinoma with asymptomatic brain metastases.

Methods

From January 2012 to June 2014, all lung adenocarcinoma patients with asymptomatic brain metastases who received treatment with erlotinib or pemetrexed as second-/third-line treatment were retrospectively reviewed. Chi-square and log-rank tests were used to perform statistical analysis.

Results

The study enrolled 99 patients, of which 44 were positive for EGFR mutation. Median progression-free survival (PFS) in months was not significantly different between the erlotinib- and pemetrexed-treated groups (4.2 vs 3.4 months; 95% confidence interval [CI]: 2.01–6.40 vs 2.80–5.00, respectively; P=0.635). Median PFS was found to be significantly longer in EGFR mutation–positive patients in the erlotinib-treated group (8.0 months; 95% CI 5.85–10.15) compared to the pemetrexed group (3.9 months; 95% CI: 1.25–6.55; P=0.032). The most common treatment-related side effect was mild-to-moderate rash and the most common drug-related side effects in the pemetrexed-group were vomiting and nausea.

Conclusion

Erlotinib and pemetrexed may be used as second-/third-line treatment in lung adenocarcinoma patients with asymptomatic brain metastases, and detection of EGFR mutation status is very important in these patients. EGFR mutation–positive lung adenocarcinoma patients with asymptomatic brain metastases showed longer PFS when treated with erlotinib as opposed to pemetrexed.

Diagnostic significance of cerebrospinal fluid EGFR mutation analysis for leptomeningeal metastasis in non-small-cell lung cancer patients harboring an active EGFR mutation following gefitinib therapy failure

BACKGROUND

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been successfully used to treat patients with non-small cell lung cancer (NSCLC) harboring EGFR mutations. However, despite an initial excellent response, recurrence within one or two years is common. Diagnosis and treatment of leptomeningeal metastasis (LM), a form of NSCLC recurrence, remains particularly difficult. Here, we analyzed the EGFR mutation status of cerebrospinal fluid (CSF) directly using real-time polymerase chain reaction (PCR) and evaluated the efficacy of therapy with erlotinib, an EGFR TKI.

PATIENTS AND METHODS

Seven NSCLC patients harboring activating EGFR mutations who had developed LM during or after therapy with gefitinib, an EGFR TKI, were retrospectively analyzed. CSF was obtained and subjected to cytological examination and EGFR mutation analysis, including detection of the resistance-associated T790M mutation, using real-time PCR.

RESULTS

In all seven cases, the EGFR mutation detected in the CSF was the same as that detected in the primary tumor (sensitivity, 100%). Conversely, cytology results were positive in only two patients (sensitivity, 28.6%). No additional T790M mutations were detected. Erlotinib was efficacious in all cases, and improved performance status was achieved for five of the seven patients. The effect of erlotinib treatment was temporary, however, with time to treatment failure (TTF) ranging from 29 to 278 days (median, 65 days) and the interval between commencement of erlotinib treatment and death ranging from 45 to 347 days (median, 168 days).

CONCLUSIONS

Analysis of EGFR mutations in CSF using a highly sensitive real-time PCR assay is a potentially powerful diagnostic method for LM.