[Investigation of Methods and Influencing Factors to Increase the Positive Rate of 
Cytological Pathology of Cerebrospinal Fluid from Lung Cancer Leptomeningeal Metastases].

BACKGROUND: In advanced non-small cell lung cancer (NSCLC), leptomeningeal metastases (LM) is a common consequence with rapid progression and a poor prognosis. LM affects roughly 3% to 5% of NSCLC patients, and it affects as many as 9.4% of individuals with epidermal growth factor receptor (EGFR) mutations. Cerebrospinal fluid cytology is the gold standard for diagnosing LM, while conventional cytopathology has a positive detection rate of less than 50%, resulting in a delay in diagnosis and treatment of LM. The fixation treatment of cerebrospinal fluid samples has a significant impact on the positive cytology detection rate, and how to improve the positive cytopathology detection rate of cerebrospinal fluid is a hot topic in clinical research. METHODS: From June 2019 to November 2021, 105 cases diagnosed with LM based on clinical symptoms and positive imaging were collected and retrospectively evaluated in the second ward of the Department of Oncology of The Second Affiliated Hospital of Harbin Medical University. The effect of different fixation methods on the positive rate of cerebrospinal fluid cytopathology was investigated, and specimens of cerebrospinal fluid were collected and sent for examination using different delivery methods, including the application of the TIB cell preservation solution kit (experimental group) and the routine application of sterile plastic tubes in lumbar puncture bags (control group). Biochemical assays (glucose and total protein) were performed on the cerebrospinal fluid fluid, and Logistic regression analysis and receiver operating characteristic (ROC) curve were used to evaluate the supplementary diagnostic value for LM patients with lung cancer. The relevance of chemical indexes in the assessment of therapeutic efficacy was examined, and biochemical (glucose, total protein) indices and cytological changes in cerebrospinal fluid fluid after pemetrexed intrathecal injection therapy were dynamically monitored. RESULTS: In the control group, 24 (45.28%) patients were positive for the first time, while 42 (80.77%) patients were positive for the first time and 10 (19.23%) patients were negative for the first time in the experimental group. Significant differences existed between the two groups (P<0.001). The results of Logistic regression analysis of patients with the first cerebrospinal fluid biochemical test showed that the risk of positive cerebrospinal fluid biochemical pathology with less than 2.5 mmol/L was 2.456 times greater than 2.5 mmol/L of cerebrospinal fluid glucose (OR=2.456, P<0.05), and total cerebrospinal fluid biochemical protein greater than 430 mg/L was 2.647 times less than 430 mg/L (OR=2.647, P>0.05). The ROC curve showed glucose sensitivity of 76.9% in cerebrospinal fluid, the specificity of 54.5%, Youden index of 0.315 and area under the curve (AUC) of 0.620, total protein sensitivity in cerebrospinal fluid of 44.4%, 90.6%, Youden index of 0.350 and AUC of 0.671. After 2 cycles of pemetrexed intrathecal treatment with complete cerebrospinal fluid cytology and cerebrospinal fluid biochemical (glucose, total protein) tests in 73 and 50 patients, respectively, the rate of cerebrospinal fluid cytology turning negative was gradually increased. Cerebrospinal fluid glucose levels increased after 2 cycles of treatment compared with the first time, with a statistically significant difference (P<0.001). CONCLUSIONS: The use of a cell preservation solution kit to immediately fix cerebrospinal fluid samples following isolation in patients with clinical symptoms and positive imaging greatly enhances the rate of positive cerebrospinal fluid cytology detection. The effect of treatment can be assessed and predicted by continuous dynamic monitoring of cerebrospinal fluid biochemistry and cytology.

[Advances in Diagnosis and Treatment of Leptomeningeal Metastasis of Lung Cancer].

Leptomeningeal metastases (LM), a special type of metastasis in advanced lung cancer, is known for its severe clinical symptoms, rapid progression and poor prognosis. LM used to be featured with low clinical diagnosis rate, limited treatment options, poor treatment efficacy, and very short survival if treatment not given. Though cerebrospinal fluid (CSF) cytology remains to be the gold standard for the diagnosis of LM, the positive rate of the first CSF cytology even in patients with suggestive clinical symptoms and positive imaging generally does not exceed 50%, leading to a delay in the diagnosis and treatment of patients with LM. With the progress of targeted therapy for driver gene-positive lung cancer and immunotherapy for driver gene-negative lung cancer, the overall survival of patients with lung cancer has been prolonged, meanwhile incidence of LM has been increasing year by year. Current clinical research in this field center around how to improve diagnosis rate and to find effective treatment approaches. This paper reviews advances in diagnosis and treatment of LM of lung cancer..
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Concordance Study of a 520-Gene Next-Generation Sequencing-Based Genomic Profiling Assay of Tissue and Plasma Samples.

INTRODUCTION: Next-generation sequencing (NGS) enables simultaneous detection of actionable somatic variants and estimation of genomic signatures such as tumor mutational burden (TMB) or microsatellite instability (MSI) status, which empowers therapeutic decisions in clinical oncology. OBJECTIVE: Our retrospective study investigated the clinical performance of somatic variant detection in paired tissue and blood samples using a large targeted gene panel, the OncoScreen Plus, which interrogates 520 cancer-related genes. METHODS: We analyzed sequencing data derived from paired tissue and blood samples of 3005 patients spanning 20 solid tumor types, including lung (n = 1971), gastrointestinal (n = 625), breast (n = 120) and gynecological (n = 110), genitourinary (n = 38), and other cancers (n = 141). RESULTS: Across tumor types, the OncoScreen Plus panel achieved a high tissue detection rate, with an average of 97.9%. The average plasma detection rate was 72.2%, with an average tissue concordance rate of 36.6%. Considering all variant types, the plasma assay yielded an average sensitivity/true positive rate of 45.7%, with a positive predictive value of 64.7% relative to tissue assay. Pearson correlation analysis revealed a strong correlation in TMB estimated from blood and tissue samples (correlation coefficient 0.845, R2 = 0.756). MSI-high status was identified in five tumor types, including endometrial cancer (28.6%), colorectal cancer (2.5%), ovarian cancer (2.0%), gastric cancer (1.5%), and lung adenocarcinoma (0.2%). CONCLUSION: Paired tumor and blood samples from a large cohort of patients spanning 20 tumor types demonstrated that the OncoScreen Plus is a reliable pan-cancer panel for the accurate detection of somatic variants and genomic signatures that could guide individualized treatment strategies to improve the care of patients with advanced cancer.

Efficacy and Safety of Intrathecal Pemetrexed Combined With Dexamethasone for Treating Tyrosine Kinase Inhibitor-Failed Leptomeningeal Metastases From EGFR-Mutant NSCLC-a Prospective, Open-Label, Single-Arm Phase 1/2 Clinical Trial (Unique Identifier: ChiCTR1800016615).

INTRODUCTION: We aimed to evaluate the efficacy and safety of intrathecal pemetrexed (IP) for treating EGFR-mutant leptomeningeal metastases (LMs) from EGFR-mutant NSCLC. METHODS: Patients with EGFR-mutant NSCLC with LM who had failed tyrosine kinase inhibitors were recruited. The dose of IP was escalated from 15 mg to 80 mg using an accelerated titration design in a phase 1 study. The recommended dose (RD) determined in phase 1 was used in the phase 2 study. The primary end point was treatment efficacy measured as the clinical response rate. Overall survival and adverse events (AEs) were evaluated as secondary end points. RESULTS: The RD observed in the phase 1 study was 50 mg pemetrexed. A total of 30 cases of LM-NSCLC were enrolled in the phase 2 study, including 14 males and 16 females. Four patients did not survive for 4 weeks and could not be evaluated for efficacy. The clinical response rate was 84.6% (22 of 26). The median overall survival of all patients was 9.0 months (n = 30, 95% confidence interval: 6.6-11.4 mo). Most AEs were mild, and the most frequent AE of any grade was myelosuppression (n = 9, 30%), which returned to normal after symptomatic treatment. CONCLUSIONS: This study revealed that 50 mg pemetrexed is the RD which results in few AEs and a good response rate. IP is an effective treatment for patients with EGFR-mutant NSCLC-LM who had failed on tyrosine kinase inhibitor.