The Riddle of the Sphinx: Progress in Leptomeningeal Metastasis of Non-Small Cell Lung Cancer

Leptomeningeal metastasis (LM) is a serious complication of advanced non-small cell lung cancer (NSCLC), and the incidence of LM has been increasing yearly in recent times. There is no consensus on the best treatment modality for LM, which underscores a difficult problem in the management of advanced NSCLC patients. The existing treatments include molecular targeted therapy, systemic chemotherapy, local radiotherapy, antivascular tumor therapy, intrathecal chemotherapy, and immunotherapy, but their efficacy is not satisfactory. In this article, we briefly describe the clinical manifestations, diagnosis, and treatment of NSCLC-LM and discuss progress regarding evaluation of the efficacy of LM treatment to better provide a necessary reference for clinical practice and clinical trial evaluation.

Sputum cell-free DNA for detection of alterations of multiple driver genes in lung adenocarcinoma

BACKGROUND

Sputum cell-free DNA (cfDNA) has been confirmed to be a valued surrogate sample for detection of EGFR mutations in patients with lung adenocarcinoma (LAC). Whether it is suitable for detection of mutations of multiple driver genes has not been reported.

METHODS

A total of 83 patients with LAC were enrolled and their sputum and paired tumor samples were collected. A next-generation sequencing (NGS)-based 10-gene panel was used to test sputum supernatant-derived cfDNA and paired tumor DNA. The sputum sediments were used for cytological evaluation.

RESULTS

The total positive rates of hotspot mutations of the 10 driver genes in sputum cfDNA and matched tissue samples were 65.1% and 77.1%, respectively. The overall detection sensitivity of variants in sputum cfDNA was 81.3% (95% confidence interval [CI], 69.2%, 89.5%) and the specificity was 100% (95% CI, 79.1%, 100%). The sensitivities of testing sputum cfDNA from patients with stage IIIB-IV was 87.0% (95% CI, 74.5%, 94.1%); the sensitivities of testing sputum cfDNA from patients with malignant sputum was 92.3% (95% CI, 78.0%, 98.0%); and the sensitivity of testing sputum cfDNA from patients with malignant sputum in stage IIIB-IV were 94.1% (95% CI, 78.9%, 99.0%).

CONCLUSIONS

This study demonstrated that sputum cfDNA were successfully used for the detection of multiple driver genes by NGS. Sputum cfDNA could be a valuable surrogate clinical sample for all-in-one test of mutations to guide target therapies, especially for patients with advanced LAC and malignant sputum.

[Auxiliary Diagnostic Value of Tumor Markers in the Cerebrospinal Fluid and Blood for Leptomeningeal Metastasis from Non-small Cell Lung Cancer]

背景与目的

软脑膜转移（leptomeningeal metastasis, LM）是指恶性肿瘤细胞浸润软脑膜，并在脑脊液（cerebrospinal fluid, CSF）中播散，预后极差，是晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）患者致死的重要原因之一，因此早期的诊断和及时的治疗具有重要意义，CSF细胞学是LM诊断的金标准，但常常伴随着检测敏感性低、无法评估疗效等问题。本文旨在探讨血清及CSF中肿瘤标志物（tumor markers, TM）在NSCLC伴LM患者诊治的临床价值。

方法

选取NSCLC伴LM患者19例，另选同期27例神经系统良性肿瘤（nonmalignant neurological diseases, NMNDs）患者作为对照组。观察比较两组患者血清和CSF中癌胚抗原（carbohydrate antigen, CEA）、糖类抗原125（carbohydrate antigen-125, CA125）、细胞角蛋白19片断抗原（cytokeratin 19 fragments, CYFRA21-1）和神经元烯醇化酶（neurone specific enolase, NSE）检测水平和检出阳性率，比较不同组TM的敏感性和特异性，并分析血清与CSF中TM检出情况相关性，最后动态监测2例LM患者血清和CSF中TM水平，分别评估颅外和颅内治疗疗效。

结果

LM组CSF和血清中TM水平和检出阳性率均高于对照组（P < 0.05），同时LM组CSF中CEA、CYFRA21-1、NSE水平高于血清，差异有统计学意义（P < 0.05）。CSF中TM检出阳性率与血清差异不具有统计学意义（P > 0.05）。CSF中CYFRA21-1敏感性最高（88.2%），CEA特异性最好（92.3%），联合指标中CEA或NSE任一项超过临界值则敏感性和阴性预测值为100%，特异性为74.1%。CYFRA21-1和NSE同时超过临界值时特异性和阳性预测值为100%，敏感性为78.9%。亚组分析显示，CSF细胞学阳性人群TM检出阳性率超过有磁共振成像（magnetic resonance imaging, MRI）异常的人群，但不具有统计学差异（P > 0.05）。LM组血清与CSF中TM检出阳性率不一致。另外，脑室中CSF与腰穿中CSF具有相同的生化性质，动态监测血清和CSF中TM浓度，可分别评估颅外和颅内病灶的疗效。

结论

血清和CSF中TM为NSCLC伴LM患者增加了一个早期辅助诊断指标，动态监测可评估治疗疗效，值得临床推广应用。

Current and future trends in non-small cell lung cancer biomarker testing: The American experience

Biomarker testing in patients with advanced stage non-small cell lung cancer provides essential information that can be used to select the most appropriate therapy. The regular updates of guideline recommendations reflect the growing number of biomarkers that must be assessed, and as such signal the shift from single-gene assays to more comprehensive genomic profiling using next-generation sequencing modalities. Cytology and small biopsy specimens have proven to be more than adequate substrates for these types of ancillary molecular testing; however, other alternative testing substrates are beginning to emerge. These include so-called liquid biopsies as well the supernatant fluid from cytology specimens, both of which have demonstrated promise for use in the clinical realm. This review will briefly cover the current state of non-small cell lung cancer biomarker testing in the United States, with a focus on these novel nonconventional substrates that are increasingly being incorporated into testing paradigms.

[Clinical Value of Cerebrospinal Fluid ctDNA in Patients with Non-small Cell Lung Cancer Meningeal Metastasis]

背景与目的

肺癌脑膜转移病死率极高。循环肿瘤DNA（circulating tumor DNA, ctDNA）已被证实含有肿瘤的基因组改变信息，并已被用于监测肿瘤的进展和对治疗的响应。对于存在脑膜转移瘤的患者，由于血脑屏障等因素的存在，外周血ctDNA不能反映脑部病灶的信息，此时脑脊液ctDNA作为检测样本能更好地体现颅内肿瘤的基因状态，指导临床对颅内病灶的靶向治疗。本研究旨在探究脑脊液ctNDA用于监测非小细胞肺癌（non-small cell lung cancer, NSCLC）脑膜转移的可行性以及脑脊液ctDNA检测对NSCLC脑膜转移的临床价值。

方法

入组NSCLC脑膜转移患者21例，通过二代基因测序技术对患者的脑脊液及外周血样本进行基因检测，并进行脑脊液细胞学病理学检测和头颅核磁共振增强检查。

结果

入组21例患者脑脊液中均检测到ctDNA。脑脊液ctDNA检测的灵敏性在脑膜转移诊断方面优于细胞学（P < 0.001）。脑脊液的基因突变检出率及基因突变丰度均高于血浆（P < 0.001）。脑脊液具有独特的基因谱。6例动态检测的患者中，脑脊液中ctDNA丰度变化均同时或早于临床疾病变化出现，可及时揭示耐药机制和监测复发趋势。

结论

脑脊液ctDNA检出率高于细胞学及影像学；脑脊液ctDNA检测可展现脑膜转移病灶特有的突变图谱；脑脊液ctDNA动态监测对肺癌患者临床疗效具有提示意义。

Unique genomic profiles obtained from cerebrospinal fluid cell-free DNA of non-small cell lung cancer patients with leptomeningeal metastases

BACKGROUND

Leptomeningeal metastases (LM), associated with poor prognosis, are frequent complications of advanced non-small cell lung cancer (NSCLC) patients, especially in patients with epidermal growth factor receptor (EGFR) mutations. Due to limited access to leptomeningeal lesions, the mutational landscape of LM has not been comprehensively investigated in large cohorts and the underlining biology of LM remains elusive. Some studies have explored the potential of cerebrospinal fluid (CSF) in reflecting the molecular profile of LM but with limited number of patients enrolled.

METHODS

In this study, we performed capture-based targeted sequencing using a panel consisting of 168 lung cancer-related genes on matched CSF and plasma samples from 72 advanced NSCLC patients with confirmed LM to interrogate the potential of CSF as a source of liquid biopsy.

RESULTS

We revealed a rate of detection of 81.5% and 62.5% for CSF and plasma, respectively (p = 0.008). The maximum allelic fraction (MaxAF) was also significantly higher in CSF (43.6% vs. 4.6%) (p < 0.001). CSF, harboring a unique genomic profile by having a significant number of CSF-specific mutations, primarily copy number variations, is superior to plasma in reflecting the mutational profile of LM. Further pathway enrichment analysis revealed that most of CSF-specific mutations participated in pathways relevant to the tumorigenesis and the development of metastases. Moreover, our data also revealed that TP53 loss of heterozygosity (LOH) predominantly existed in CSF (p < 0.001).

CONCLUSIONS

Collectively, we demonstrated that CSF provides a more comprehensive profile of LM than plasma in a large cohort, thus can be used as an alternative source of liquid biopsy for LM patients.

Leptomeningeal metastasis from solid tumors: clinical features and its diagnostic implication

In this study, we examined the characteristics and aimed to increase the knowledge of clinical features of leptomeningeal metastasis (LM). The clinical data, including initial diagnosis and treatment of primary tumor, clinical manifestations, neuroimaging findings, cerebrospinal fluid (CSF) examination, were analyzed. For the patients with adenocarcinoma/breast cancer, the incidence of cranial lesions and cranial nerve paralysis was obviously higher than patients with small cell lung cancer. Whereas, the incidence of involvement of intravertebral canal was obviously lower than that of small cell lung cancer. Patients with adenocarcinoma/breast cancer showed more incidence of leptomeningeal enhancement compared to those with small cell lung cancer. Persistent severe headache was noticed in those with squamous carcinoma, and usually showed absence of abnormally LM-related neuroimaging and CSF cytological findings, which resulted in a challenge in the diagnosis of LM from squamous carcinoma. Patients with different primary tumors showed differential clinical features. Significant differences were observed in clinical features between patients with adenocarcinoma/breast cancer and small cell lung cancer. Our study contributes to the understanding of clinical characteristics of LM, and contributes to improvement of LM diagnosis in clinical practice.