Safety and Efficacy of Whole Brain LDRT+ICI+Intrathecal Chemotherapy in Refractory Meningeal Metastasis of Lung Cancer

Inclusion criteria

• ≥ 18 years old and ≤ 75 years old;
• Patients with a definite diagnosis of leptomeningeal metastasis by cerebrospinal fluid cytology, or patients with clinical diagnosis combined with tumor history, neuroimaging, clinical manifestations, cerebrospinal fluid examination, etc.;
• Patients with a clear history of lung carcinoma, including histopathological diagnosis or a combination of cytopathology and imaging, and failure of standard treatment;
• Efficacy of extracranial lesions SD;
• Patients with no contraindications to craniocranial radiotherapy were judged by radiotherapy doctors. Subjects who agree to receive immunotherapy, Lumbar puncture, intrathecal chemotherapy, and radiotherapy;
• Expected survival ≥3 months, PS score ≤3;
• Agree to provide cerebrospinal fluid, blood and tissue samples for biomarker testing;
• The main organs function normally, no serious blood, heart, lung, liver, kidney, bone marrow and other functional abnormalities and immune deficiency diseases;
• One week before enrollment, bone marrow and liver and kidney function met the following criteria:
• ① Hemoglobin ≥80 g/L, neutrophils ≥1.5×10\^9/L and platelets ≥70×10\^9/L;
• ② Renal function: Cr≤ULN (upper limit of normal) × 1.5, endogenous creatinine clearance (Ccr)≥55 ml/min; Liver function: total bilirubin ≤ULN × 1.5; ALT, AST≤ULN × 2.5; (In case of liver metastasis, total bilirubin should not be higher than 3 times the upper normal limit, and transaminase should not be higher than 5 times the upper normal limit);
• The fertile women agreed to use contraception during the study period and for 6 months after the study ended; Patients who tested negative for a serum or urine pregnancy test within 7 days prior to joining the study and were not breastfed; Men who agreed to use contraception during the study period and for 6 months after the study ended

Exclusion criteria

• Active autoimmune disease or history of autoimmune diseases;
• Congenital or acquired immunodeficiency;
• Uncontrolled cardiac clinical symptoms or diseases;
• Severe infection or severe comorbidities, such as bleeding peptic ulcer, ileus, heart failure, renal failure, or poorly controlled diabetes;
• History of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation;
• Other systemic malignancies within the last 5 years;
• Allergy to any test drug;
• Uncontrolled epilepsy, neurological failure, or severe treatment-related neurological impairment, uncontrollable psychosis, and other conditions deemed unsuitable for inclusion by the investigator;
• Pregnant and lactating women, subjects with reproductive capacity are unwilling to take effective contraceptive measures.