protocolSection identificationModule nctId: NCT06346977, orgStudyIdInfo id: DTO-20231214, briefTitle: Diagnosis of Leptomeningeal Metastasis and the Monitoring of Intrathecal Chemotherapy Efficacy in NSCLC, statusModule overallStatus: NOT_YET_RECRUITING, startDateStruct date: 2024-04-01, primaryCompletionDateStruct date: 2024-12-31, completionDateStruct date: 2024-12-31, studyFirstPostDateStruct date: 2024-04-04, lastUpdatePostDateStruct date: 2024-04-04, sponsorCollaboratorsModule leadSponsor name: Wuhan Union Hospital, China, class: OTHER, descriptionModule briefSummary: Non-small cell lung cancer (NSCLC), occupying a disquieting position as the second most prevalent and deadliest neoplasm worldwide, afflicts an estimated 30% of its patients with intracranial metastatic spread. Among these, leptomeningeal metastasis (LM) is an exceptionally surreptitious and perilous manifestation, often evading timely and accurate diagnosis. The clinical landscape is further complicated by the presence of patients who, due to various reasons, are unable to undergo lumbar puncture, a procedure crucial for the investigation of LM. Moreover, even when cerebrospinal fluid (CSF) analysis via conventional cytological and immunohistochemical methods is attempted, a definitive diagnosis of LM may remain elusive in a subset of cases.Intrathecal chemotherapy, particularly via the administration of pemetrexed, which has demonstrated both notable efficacy and an acceptable safety profile when delivered directly into the cerebrospinal space, constitutes a cornerstone of treatment for NSCLC-LM. Despite its importance, the lack of robust, validated biomarkers to gauge the therapeutic response to such interventions represents a significant knowledge gap. This deficit is compounded by the inherent challenges associated with CSF samples, including their limited availability and the suboptimal sensitivity and high resource demands of current ctDNA assessment techniques.To address these pressing diagnostic and monitoring needs in NSCLC-LM management, the investigator proposes a forward-looking, non-interventional clinical study harnessing the power of cutting-edge proteomic technologies. These platforms, characterized by their high throughput, exquisite sensitivity, and minimal sample volume requirements, offer a promising avenue for elucidating the intricacies of chemotherapy response in intrathecal therapy. The study aims to provide valuable insights into improving diagnostic accuracy for LM in NSCLC patients and to establish a more rigorous framework for assessing treatment efficacy in individuals undergoing intrathecal chemotherapy, ultimately contributing to enhanced patient care and personalized therapeutic strategies., conditionsModule conditions: Diagnosis, designModule studyType: OBSERVATIONAL, designInfo observationalModel: COHORT, timePerspective: PROSPECTIVE, enrollmentInfo count: 60, type: ESTIMATED, armsInterventionsModule interventions name: Pemetrexed, outcomesModule primaryOutcomes measure: Progression-free survival (PFS), secondaryOutcomes measure: Overall survival (OS), eligibilityModule sex: ALL, minimumAge: 18 Years, stdAges: ADULT, stdAges: OLDER_ADULT, contactsLocationsModule locations facility: Union hospital, city: Wuhan, state: Hubei, zip: 430000, country: China, geoPoint lat: 30.58333, lon: 114.26667, hasResults: False